Physiol Rev 92: 521–536, 2012
doi:10.1152/physrev.00031.2011
100 YEARS SINCE SCOTT REACHED THE POLE:
A CENTURY OF LEARNING ABOUT THE
PHYSIOLOGICAL DEMANDS OF ANTARCTICA
Lewis G. Halsey and Mike A. Stroud
University of Roehampton, London, and National Institute for Health Research Biomedical Research Unit in
Nutrition, Southampton University Hospitals Trust, Southampton, United Kingdom
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LIFE AND DEATH IN THE...
POLAR TEMPERATURES
ENERGY EXPENDITURE AND ENERGY...
WATER
VITAMIN C
SLEEP
THE POLAR PLATEAU
COULD SCOTT HAVE SURVIVED?
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I. LIFE AND DEATH IN THE ANTARCTIC
There is just one continent that supports no permanent
inhabitants: Antarctica. Indeed, the terrestrial Antarctic offers little for any large animal species; few vertebrates (seabirds and seals) live further inland than the coast, and they
typically spend much of their lives at sea. There is minimal
vegetation or animal matter for food, and with temperatures regularly down to ⫺70°C accompanied by strong katabatic (downslope) winds, the interior of the Antarctic is as
inhospitable to human living as are the heights of Everest,
and terrestrial travel on the continent is incredibly demand-
ing. Towards the start of the 20th century, in the early days
of Antarctic exploration, travel there was accomplished using huskies and cold-weather ponies with varying degrees of
success, with much of the food and equipment transported
by the explorers themselves, on foot. Long expeditions of
this type, with little or no aid from mechanical or animal
power, represent a huge physiological challenge for three
environmental reasons. First, as a consequence of our African ancestry, we are far more suited physiologically to heat
than cold. Second, man-hauling, which is very physically
arduous, in combination with the extremely low temperatures, results in levels of energy expenditure so high that the
sledging rations which can be pulled (and on some expeditions bolstered by rations stored partway along the route in
advance) do not provide sufficient calories to compensate.
Third, the most severe area of Antarctica, the polar plateau,
is at high altitude (average effective: 2,800 m), resulting in
problems of hypoxia in combination with particularly cold
ambient conditions.
When the first Antarctic explorers broached its terrain, published knowledge of human physiological responses to this
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Halsey LG, Stroud MA. 100 Years Since Scott Reached the Pole: A Century of
Learning About the Physiological Demands of Antarctica. Physiol Rev 92: 521–536,
2012; doi:10.1152/physrev.00031.2011.—The 1910 –1913 Terra Nova Expedition to the Antarctic, led by Captain Robert Falcon Scott, was a venture of science and
discovery. It is also a well-known story of heroism and tragedy since his quest to reach
the South Pole and conduct research en route, while successful was also fateful. Although Scott
and his four companions hauled their sledges to the Pole, they died on their return journey either
directly or indirectly from the extreme physiological stresses they experienced. One hundred years
on, our understanding of such stresses caused by Antarctic extremes and how the body reacts to
severe exercise, malnutrition, hypothermia, high altitude, and sleep deprivation has greatly advanced. On the centenary of Scott’s expedition to the bottom of the Earth, there is still controversy
surrounding whether the deaths of those five men could have, or should have, been avoided. This
paper reviews present-day knowledge related to the physiology of sustained man-hauling in Antarctica and contrasts this with the comparative ignorance about these issues around the turn of the
20th century. It closes by considering whether, with modern understanding about the effects of
such a scenario on the human condition, Scott could have prepared and managed his team
differently and so survived the epic 1,600-mile journey. The conclusion is that by carrying rations
with a different composition of macromolecules, enabling greater calorific intake at similar overall
weight, Scott might have secured the lives of some of the party, and it is also possible that
enhanced levels of vitamin C in his rations, albeit difficult to achieve in 1911, could have significantly
improved their survival chances. Nevertheless, even with today’s knowledge, a repeat attempt at
his expedition would by no means be bound to succeed.
LEWIS G. HALSEY AND MIKE A. STROUD
FIGURE 1. Captain Scott, 1911. (Photograph by Herbert Ponting;
licensed with permission of the Scott Polar Research Institute, University of Cambridge, Cambridge, UK.)
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This paper develops a short essay (45) reviewing present
understanding of human physiological responses to the interconnected stressors experienced by Antarctic explorers.
Current knowledge on relevant aspects of cold exposure,
the energy costs of man-hauling, macro- and micronutrient
demands, dehydration, and the effects of sleep deprivation
and altitude are reviewed, while flagging up the key areas of
scientific ignorance on these topics in Scott’s time. This
article then considers the most poignant question: accepting
the limitations of the technologies he took on the expedition, had Scott been privy to modern physiological knowledge, could he and his team have returned home alive?
II. POLAR TEMPERATURES
The most overtly hostile aspect of the Antarctic environment is its exceptionally low temperatures which, even during the austral summer when the majority of terrestrial
travel is undertaken, are normally below 0°C and can often
drop below ⫺40°C. The thermoneutral zone of a naked
person is quite high at ⬃28 –31°C, and still above 10°C
even when clothed with fairly insulating garments (34). At
environmental temperatures below the thermoneutral zone,
the body will try to defend core temperature through a
combination of physiological and behavioral responses that
increase heat production and decrease heat loss (e.g.,
Ref. 71).
The human body reacts to either cold skin, or a decrease in
core body temperature from 37°C down to ⬃35°C (94), by
retaining more heat through an increase in body insulation
and generating more heat through shivering (and possibly
passive nonshivering mechanisms; Refs. 30, 87, 94). In
Scott’s time, the thermoneutral zone had not been quantified, and Scott was unaware of how cold it could become in
Antarctica during March (106, entry 12th Mar 1912; “message to the public” Mar 1912, Ref. 108). There was also
inadequate understanding of the phenomenon of wind chill
(87), which was not empirically assessed until the 1950s by
Admiral Byrd during a solo overwintering expedition in
Antarctica, with its detrimental effect of increased metabolic rate documented only recently (137). Furthermore,
early Antarctic explorers hoped that chronic exposure to
the cold would invoke valuable physiological adaptation,
although it is now understood that the level of adaptation
achieved is not of practical significance for survival. Since
the vast majority of human evolution occurred around the
equator, humankind is adapted primarily to heat exposure,
and physiological adaptations to the cold are not only relatively ineffective (e.g., Ref. 77) but can be counterproductive for man-hauling expeditions in extreme conditions.
Shivering, which involves involuntary, rhythmic muscle
contractions that generate heat in a similar manner to exercise, can produce up to 4 mets (5 kcal/min) (123) compared with up to ⬃18 mets (around 22 kcal/min) produced
by high-intensity voluntary physical activity. Increasing
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environment was minimal, while today, although there is
still much to learn, we have a far better understanding of its
extreme and fascinating effects on the human condition.
The hardship of man-hauling in the Antarctic in the early
days was undoubtedly exacerbated by the availability of
less advanced technologies, in particular in terms of clothing, sledges, and fuel storage. Nonetheless, modern-day unsupported explorers, which include the author Mike Stroud,
experience the same gamut of physiological stresses and,
somewhat paradoxically, while some of their equipment is
superior, that superiority enables them able to pull larger loads
for longer. Beyond alterations in the macronutrient balance
of the rations to enable greater calorific intake at similar
overall ration weights and the ingestion of vitamin C-rich
foods, an infamous omission to the rations eaten by most
early polar explorers, it is therefore questionable whether
today’s Antarctic adventurers would manage a manhauling expedition much differently from Captain Robert
Scott (FIG. 1), who, 100 years ago, led a team from Ross
Island to the South Pole (FIG. 2) but tragically perished with
his men on the way back to the continent’s edge from natural causes induced by acute, chronic physiological stresses.
THE PHYSIOLOGICAL DEMANDS OF ANTARCTICA
physiological insulation, afforded by cold-induced vasoconstriction in the skin and superficial muscles, amounts to
less than the insulation provided by a standard business suit
(94), and the marked reductions in superficial blood flow
greatly increase risk of both nonfreezing neurovascular cold
injury (4) and frostbite (the growth of ice crystals in and
around cells, which at worst can be extremely damaging to
large body areas; 106, entry 18th Mar 1912). Even with
modern clothing, the cold-induced vasoconstrictor responses therefore remain very problematic (47). While
there is some evidence that with repeated cold exposure
there are more complicated adjustments to peripheral blood
flow with selective peripheral vasodilation (63, 64, 69, 99),
these acclimative changes are inadequate to prevent cold
injuries and any vasodilation increases rates of body heat
loss. Furthermore, the vasoconstrictor responses to cold
may also be impaired after multiple days of severe physical
exertion (19; see also Ref. 20), and in Scott and his men, it
was also likely to have been impaired by their smoking.
In addition to the increased energetic demands of keeping
the body warm and the risks of hypothermia or debilitating
frostbite, Antarctic temperatures also result in greater fatigue during exercise (92, 123) and a reduced maximal
power output (for a review, see Refs. 87, 89), both very
detrimental to man-hauling a sledge given the high physical
demands. Furthermore, such cold temperatures result in
impairment to cognition and psychomotor performance
such as reasoning and learning (95), and dexterity (123),
although the human body may somewhat acclimatize to the
cold in these respects (though see Ref. 73).
Since the first explorations of the Antarctic terrain, it has
been evident that during man-hauling expeditions the most
effective method of defending from the cold is by undertaking the work required to pull the sledges. This generates
considerable heat as a valuable result of inherent muscle
inefficiency. For instance, several layers of clothing are required to alleviate shivering in a person who is stationary in
an ambient temperature of 5°C while an office suit is sufficient at ⫺18°C during periods of activity (115). Nevertheless, early explorers did recognize that a few relatively thin
layers were not really sufficient in very low Antarctic temperatures, even with the hard work of man-hauling (108, p.
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FIGURE 2. The route taken by Scott and his men during their journey to the South Pole from Ross Island,
which ended in their deaths during the return leg as they retraced their steps. Due to the persistent presence
of the Ross ice shelf, it is possible to walk from Ross Island to the Antarctic land mass. [From Halsey and Stroud
(45), with permission from Elsevier.]
LEWIS G. HALSEY AND MIKE A. STROUD
III. ENERGY EXPENDITURE AND ENERGY
INTAKE DURING MAN-HAULING
A. Metabolic Costs of Sledge Pulling
Pulling sledges across snow and ice in the Antarctic is so
physically demanding (see 106, entry 11th Jan 1912) that
overall calorie expenditure far exceeds the calorie costs of
coping with the severe cold. In Scott’s time, it was known
that greater muscular work during exercise was met by
physiological changes, particularly cardiorespiratory (61),
resulting in higher energy expenditure and hence larger
food requirements. Yet despite early pioneering studies in
particular by Zuntz (140), there was little information on
how human energy requirements changed with type and
intensity of activity.
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Once a reliable equivalence between oxidation rate and
heat loss was observed, it became more straightforward to
measure human energy expenditure as rate of oxygen consumption via indirect calorimetry (128). However, in the
main, studies measuring energy expenditure in people during activity were only published from soon after Scott’s
Terra Nova expedition (e.g., Refs. 14, 61), and it was several decades more until an informative amount of data on
the costs of human walking on different terrains became
available (3, 12, 90). Thus, just after the turn of the century,
there was minimal understanding of the power required to
sledge pull and how that could change with differing snow
conditions and walking gradients.
In fact, not until Mike Stroud measured energy expenditure
in man-haulers over several polar expeditions during the
1980s and 1990s was the very high energy costs of polar
travel on foot appreciated. During a modern-day, one-way
expedition to the South Pole that repeated Scott’s route
(“Footsteps of Scott expedition”), an average 25 MJ (6,000
kcal) were expended every 24 h (111, 113), whilst on a foot
crossing of Antarctica by Stroud and Sir Ranulph Fiennes in
the austral summer of 1992–1993, the two men expended
on average 28 MJ/day (nearly 7,000 kcal/day). This included a period of ⬃10 days while ascending to the plateau
averaging 46 MJ/day (nearly 11,000 kcal/day) (112). These
incredibly high values are best appreciated compared with
the estimate of 25 MJ/day (6,000 kcal/day) in a male distance runner covering ⬃100 km/day for 1,000 km (29), 30
MJ/day (over 7,000 kcal/day) in two elite male cyclists averaging around 330 km/day for 10 days (39), and 27 MJ/
day (6,500 kcal/day) in elite cyclists working in a team to
cover in total nearly 4,900 km in 6 days (Race across America, RAAM; Ref. 54). Indeed, sledge-pulling up to the polar
plateau requires energy expenditures of a considerably
greater higher daily rate than even exhibited by Tour de
France competitors (134) and professional cross-country
skiers during training (107). This is presumably possible
because, despite the lower fitness levels of man-haulers
compared with those of modern-day elite athletes, sledgepulling on Antarctic treks is typically undertaken during the
majority of waking hours (typically 10 –12 h), whereas the
Tour de France typically demands on average 4 –5 h of
cycling per day while professional cross-country skiers train
for 2.5– 4 h/day (107). Furthermore, man-hauling invokes
the use of many muscles in the body including those in the
torso and arms. FIGURE 3 summarizes comparisons in daily
energy expenditure and distances achieved between modern
Antarctic expeditions and elite athletes during endurance
racing and training. Such rates of energy expenditure during
man-hauling explorations require daily food rations to satisfy them which are greater than can be pulled on a sledge
for long journeys and man-haulers traveling for many days
are therefore exposing themselves to an inevitable starvation diet.
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109). It is therefore during periods of lower activity that the
body is most vulnerable to the cold (1, 106, entry 12th Mar
1912), especially after exhaustive exercise since this increases susceptibility to hypothermia (19). Thus erecting a
tent in the Antarctic can be particularly dangerous, and if
during such relatively low activity core temperature drops
towards 30°C, hypothalamic control is lost and unconsciousness ensues with the body incapable of escaping coldinduced death unaided. In recent times there have been a
number of experiments specifically looking at physiological
responses to exercise in cold, wet, and windy conditions. In
a wet, windy environment with an ambient temperature of
5°C, so long as exercise intensity is fairly high, for example,
a strong pace of walking, there is no change in core body
temperature or rate of energy expenditure compared with
thermoneutral conditions (129). Indeed, during periods of
man-hauling, sweating and peripheral vasodilation occurs,
necessary to dissipate the excess heat produced (60). However, if the work rate is lower, even though this still represents walking at a standard pace (129), core temperature
decreases by around 1°C while rate of energy expenditure
rises (probably primarily due to shivering; Ref. 87), indicating that heat production from the exercise does not offset
heat lost to the cold environment. Furthermore, when exposed to cold, individuals with lower body fat levels and
who are older are prone to greater heat loss and thus presumably higher rates of shivering and energy expenditure
(17). Detrimental effects from exercise-induced carbohydrate depletion can also occur as hypoglycemia impairs
control of body temperature (40), limiting the ability to
shiver or vasoconstrict the periphery. Thus, as a man-hauling expedition unfolds and the fat levels of the participants
decrease, eventually the amount of energy lost to shivering
increases while the effectiveness of exercise and shivering at
warming the body core becomes progressively less (87).
Scott was clearly unaware of this process (106, entry 12th
Jan 1912), yet such spiraling deterioration was certainly
instrumental in the deaths of him and his men.
THE PHYSIOLOGICAL DEMANDS OF ANTARCTICA
FIGURE 3. Daily energy expenditures (bars) and distances covered (squares) by man-haulers on modern
Antarctic expeditions and elite endurance athletes racing or training. F/S indicates Fiennes and Stroud.
There are two key problems that result from large reductions in body mass in the Antarctic. First, there is an increased chance of hypothermia since reduced fat stores increase heat loss, absolute heat content of the body is reduced, and muscle protein stores decrease heat production
from muscular power and shivering. Second, ability to pull
a sledge decreases (4), reducing daily mileage and hence
elongating exposure to the environment that is causing the
weight loss.
Once fat and protein reserves are run down, the body is
forced to consume vital tissues (even in the extremes of
modern-day body building, elite contestants have 3– 6%
body fat levels; Ref. 105). Physiological functions begin to
deteriorate, and cardiovascular capacity markedly decreases. Mass loss in extremis results in glucose stores becoming exhausted causing hypoglycemia, and although for
a while the body adapts to using other substrates in the
central nervous system such as ketones and lactate (118),
the amounts of these are very limited and soon the body
becomes too weak to function properly. Ultimately, metabolic rate will decrease to a point that insufficient heat is
produced and too much is lost to prevent deep hypothermia
and death from cardiac arrest; in Scott’s case, cardiac arrest
may well have been hastened by severe dehydration.
Scott appreciated, at least through experience of hunger
himself (96, p. 63, 73) and by his men during previous
man-hauling trips, that sledging rations did not always negate body mass loss (e.g., 106, entry 21st November 1911).
However, he was wholly unaware of how insufficient the
rations he took to the South Pole were relative to energy
expenditure, in particular when man-hauling. A previous
expedition by Ernest Shackleton, which got to within just
over 180 km (112 miles) from the south pole in 1908, had
(incorrectly) determined that required rations per day
amounted to 34 ounces (964 g) (76), similar to the mean
weight of rations used by Scott (100). Unfortunately for
Scott, the evidence from a 35-day trip by three of his men
who man-hauled to Cape Crozier to collect penguin eggs
during the same expedition to the Antarctic and just months
before Scott’s assault on the Pole suggested this size of ration was indeed more or less sufficient. Each of the three
men: Edward Wilson, Henry Bowers, and Apsley CherryGarrard, lost between just a half and two kilograms of mass
(35). Key aspects of this journey were similar to the subsequent polar journey, most notably pulling the sledges on
often sticky ground (see 108, p. 35–36 and 140 –141 for an
explanation of this phenomenon) and with a weight to pull
per man starting at more than 100 kg. Thus perhaps the
most likely reason as to why the men lost little body weight
on the earlier journey was because compared with the polar
journey they spent a smaller proportion of time active. They
progressed on average 6.5 km (4 miles) per day on the
earlier journey (though with some relaying of sledges,
which increases distances walked) versus 18 km (11 miles)
per day on the polar journey (though man-hauling for only
70% of this). It was also likely that early explorers tended to
underestimate levels of muscle and fat loss from reductions
in weight over an expedition since in Scott’s era it was not
appreciated that the body retains fluids in response to malnutrition (hunger edema; Refs. 82, 116).
Despite Scott’s “standard” rations (consumed while off the
polar plateau) providing around 17.6 MJ (4,200 kcal) per
day (FIG. 4), and “summit” rations (for plateau use) providing around 19 MJ (4,500 – 4,600 kcal) per day (35, 96), his
daily calorie deficits probably peaked as high as 27 MJ
(6,500 kcal; see also Ref. 106, entry 13th December 1911).
Previous estimates have suggested that those deficits may
well have averaged 6 –12 MJ (1,500 –3,000 kcal) (94, 96,
111), or even somewhat more given up-to-date calculations
of the net energy gained from food digestion (68). With the
assumption that Scott had lost around 40% of his body
weight at time of death, about the maximum amount possible for a person who begins with a relatively low body
mass index (28), he would have lost around 1.3 kg of body
mass on average each week, which represents a mean daily
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B. Exercise Starvation
LEWIS G. HALSEY AND MIKE A. STROUD
calorie deficit of close to 6.3 MJ (1,500 kcal) assuming an
average protein ratio of ⬃0.3 for endogenous energy metabolized (28). This value is at the lower end of previous
estimates perhaps because the men periodically ate pony
meat to supplement their rations once these transport animals had been slaughtered on the first part of the outward
journey. The inevitable weight loss is documented by Scott’s
team (e.g., Ref. 106, entry 28th Jan 1912), and towards his
final days of man-hauling, fat reserves and blood glucose
levels would have been close to zero.
Since Scott did not appreciate the scale of his likely energyinduced calorie deficit, in contrast to modern man-haulers
(118), he did not make an obvious attempt to increase body
mass before the start of his assault on the South Pole. Nevertheless, even in his time it was understood that there is an
inverse association between initial adiposity and the contribution of protein as fuel during a period of starvation (127),
although quantitative assessments of this effect were only
made recently. It is now known from the Minnesota experiment of semi-starvation that the fraction of fat-free mass
lost at the point that fat stores are fully depleted is not
influenced by percentage body fat at the start of a period of
starvation (28), although such data are not available for
man-haulers. This partitioning of protein and fat reserves,
such that both reach complete depletion simultaneously, is
likely to ensure maximum length of survival. However,
there is variation between individuals in the fraction of
body protein that can function as the protein energy reserve,
and this probably affects the percentage of weight that can
be lost during starvation and the proportion of tissue types
lost (28).
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C. Proportions of Macronutrients
By 1905, the proportions of protein, fat, and carbohydrate
typically metabolized by people were known (5), providing
a useful basis for assessing the approximate ratios of these
macronutrients needed for a standard healthy diet. However, man-hauling sledges in extremely low ambient temperatures is clearly not typical, and in Scott’s time there was
little information on the relative merits of the different
sledging diets employed on earlier expeditions, although
scientific opinion of the day suggested particular inclusion
of fatty foods (106, entry 27th May 1911). Scott attempted
to garner some evidence about the best ratios of macronutrients for sledging from the aforementioned journey to collect penguin eggs at Cape Crozier (106, entry 19th June
1911) with Wilson, Bowers, and Cherry-Garrard purpose-
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FIGURE 4. Standard ration eaten per day per man by Scott and his
men. This comprised biscuits, pemmican, butter, sugar, chocolate,
cocoa, cereals, and raisins (100) and represented ⬃17.6 MJ
(4,200 kcal) (35, 96). Per day, Scott’s team were expending between 1,500 and 3,000 kcal more than they were ingesting (94,
96, 111). See main text for further details. (Photograph by Herbert
Ponting; reproduced with permission of the Scott Polar Research
Institute, University of Cambridge, Cambridge, UK.)
Since the ground-breaking work of Max Rubner (102) in
the 19th century on respiration calorimetry, there has been
direct evidence that larger organisms tend to have a higher
resting rate of energy expenditure, and this evidence had
grown considerably by 1910 (see Ref. 18 for a history of
early metabolism studies). The presence of this relationship
in humans would have been intuitively clear to Scott (see
also Refs. 21, 96, p. 73) and has been confirmed empirically
many times (e.g., Ref. 50). Edgar Evans was the first man to
die during Scott’s fateful journey to the South Pole. He was
also the heaviest and is therefore likely to have suffered the
greatest calorie deficit and so utilized his endogenous body
stores at a quicker rate (e.g., Ref. 106, entry 28th January
1912). Similarly, Fiennes, who is considerably heavier than
Stroud, experienced a greater drop in body mass during
their 96-day expedition across Antarctica (24.6 vs. 21.8 kg;
Ref. 118), and the larger men on a one-way expedition to
the South Pole also experienced greater decreases in weight
(111). The same pattern was found in two men pulling
sledges on skis across Greenland (38). However, there are
also certain energetic advantages for larger people in manhauling situations. Evans and Fiennes would likely have
benefited from larger initial endogenous body stores compared with their respective compatriots, lower mass-specific
resting metabolic rates, and greater stride length hence
lower stride frequency (41, 110). Thus it is unclear whether
fasting endurance, i.e., the time until energy stores are exhausted (50), will tend to be greater in larger or smaller
man-haulers. There is evidence, however, that while pulling
a sledge particularly hard (e.g., uphill towards the polar
plateau), smaller men expend energy faster, which may
have a detrimental effect on the deterioration of the muscles, which are clearly important for sustained sledge pulling. Stroud lost considerably more muscle mass than did
Fiennes during their trans-Antarctica expedition (6.5 vs. 4.3
kg) (117, 118), and this is perhaps due to the fact that
Stroud depleted his available energy stores at a faster rate
(total body mass loss during expedition: 26 vs. 29%) and so
experienced increased muscle catabolism sooner.
THE PHYSIOLOGICAL DEMANDS OF ANTARCTICA
Antarctic have carried rations averaging 21.3 MJ/day
(⬃5,000 kcal/day) (112), consisting of 57% fat which provides 39.7 kJ/g (9.5 kcal/g) and only 8% protein which
provides 18.4 kJ/g (4.4 kcal/g) (FIG. 6). The main consequence of these more modern polar rations is that due to the
high energy density of fat, they have a higher energy density
than those rations used by Scott, which means that although
they weigh about the same as the earlier rations, they contain on average ⬃2,900 kJ (700 kcal) more energy per day.
fully eating different proportions of available foods, at least
during the first part of the journey. They reported that too
much fat or carbohydrate made the food unpalatable. However, the energy content of macronutrients had been measured by this time (47a), and Scott knew that the energy
density of fat is particularly high, hence his rations had a far
greater fat content than any previous polar ration (FIG. 3)
(35). His “summit rations” for the polar plateau consisted
of biscuit, pemmican, butter, sugar, cocoa, and tea, which
provided ⬃210 g of fat (24% of the ration), 257 g of protein
(29%), and 417 g of carbohydrate (47%) per day (100).
The proportions of macronutrients in his standard rations
were similar (111) (FIG. 5).
Nonetheless, not only did the rations eaten by the first manhaulers in the Antarctic typically provide inadequate energy, but they probably still contained too little fat, and too
much protein, to be optimal (see also 106, entry 26th February 1912). More recent man-hauling expeditions in the
This protein intake of these more modern rations may
sound surprisingly low in the context of wishing to maintain muscle mass and strength, but there is little evidence
that high levels of exercise require increased protein intakes,
and the 8% protein content, amounting to ⬃80 g/day, easily exceeds the amount required to maintain nitrogen balance. Similar ratios of macronutrients were also consumed
by Alex Hibbert and George Bullard in 2008 during the
longest unsupported polar journey in history (a crossing of
the Greenland icecap, Ref. 51).
Scott probably believed that the high levels of muscular
exercise during man-hauling need support from a particularly high intake of protein, since the first studies of protein
requirements postulated that muscles were broken down to
some degree during contractions as an energy supply (79).
Even today the dietary protein needs of very prolonged
activity are poorly understood. For example, while Stroud
(112) notes that various authors have recommended intakes
of between 1.3 and 1.6 g/kg during periods of intensive
exercise (e.g., Ref. 121), this may not be necessary in fully
trained individuals (83). Furthermore, it is interesting to
note that for some populations of humans “natural” levels
of protein digestion are high (e.g., Refs. 9, 75) and up to
50% of total energy intake (24). However, most studies into
protein needs are based on scenarios of energy balance as
FIGURE 6. Representation of the daily ration typically eaten by Alex Hibbert during an 8-day Greenland speed
crossing expedition in 2011. The 2 kg ration provided 36,000 MJ (8,600 kcal) of energy, as ⬃63%
carbohydrate, 26% fat, and 11% protein. (Photograph adapted with permission from one provided by Alex
Hibbert, http://www.alexhibbert.com.)
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FIGURE 5. Daily energy intake provided by rations on Scott’s expedition to the South Pole (“standard” rations; “summit” rations) and
by rations for the crossing of Antarctica by Fiennes and Stroud
(F/S). Light gray represents the amount of energy provided by
carbohydrate, mid gray represents energy provided by fat, and dark
gray represents energy provided by protein.
LEWIS G. HALSEY AND MIKE A. STROUD
It might also be thought that the more modern Antarctic
rations described above are relatively low in carbohydrate,
since there is some evidence that diets containing ⬃70%
energy as carbohydrate can enhance the endurance of some
marathon runners (125). Indeed, present-day man-haulers
when undertaking relatively short expeditions and traveling
at a higher average speed often choose rations that are
mostly carbohydrate (FIG. 6). However, the plodding work
of man-hauling, conducted at a low average energy intensity, particularly the case during long-distance expeditions,
is well suited to fat, a substance that can only be metabolized aerobically, as opposed to carbohydrate utilization.
This is because unlike marathon running, man-hauling is
less affected by the body’s limitations in sourcing oxygen.
Furthermore, high levels of fat ingestion probably increase
the time it is possible to sustain intense man-hauling, since
even with the lower aerobic work rates, whole body glycogen stores will be run down after 2–3 h of 8- to 10-h work
days regardless of the amount ingested (112), and so beyond this time muscles have to utilize fat as the primary
energy substrate anyway. This is because the maximum rate
at which exogenous carbohydrate can be oxidized is ⬃1
MJ/h (240 kcal/h) (56) while man-hauling activities may
require up to four times that rate of energy provision (112).
Indeed, both Stroud and Fiennes experienced periods of
hypoglycemia towards the end of their 96-day trip despite
the fact that the likelihood of this happening was probably
528
reduced by the high-fat diets they ate both prior to and
during their expedition, which probably allowed some adaptation through optimizing mitochondrial fat oxidation
(48, 62, 85, but see also Ref. 49).
Nevertheless, in spite of all the new information available,
modern explorers remain uncertain about the optimal ratio
of dietary substrates for activity of extreme length in Antarctica (112). While high-fat, high-carbohydrate diets are
likely best, it is possible that at least some people are incapable of absorbing a high-fat diet well (4, 111), which
would reduce the effective calorie content of such rations.
Furthermore, the excessive muscle loss and hypoglycemia
experienced in particular by Stroud while crossing Antarctica may indicate that modern-day rations have tended to
contain a suboptimal proportion of carbohydrates, possibly
in part because shivering is largely fuelled by them.
IV. WATER
There was no appreciation in Scott’s time of the effects that
even mild decreases in body water can have, yet rates of
water loss are typically high during periods of man-hauling
such that even on modern expeditions, short-term dehydration is likely, particularly since cold exposure attenuates
thirst (58). The intensity of pulling a sledge triggers sweat
production on all but the coldest days and also of course
elicits high breathing rates (106, entry 17th December
1911) which, coupled with the dry air of the cold Antarctic
environment and the phenomenon of cold diuresis (66),
exacerbates water loss (25). This is particularly the case on
the polar plateau where altitude leads to even higher respiratory rates and increased diuresis (114, 119). Dehydration
causes depletion of circulating blood volume (27) and general deterioration in thermoregulatory efficiency during exercise (80). A net of around 5 liters of body fluid can be lost
per day and results in noticeable reductions both in physical
performance (80) and cognitive functions such as concentration and judgement (42), affects sleep, and increases the
chances of peripheral cold injury and mountain sickness at
altitude (7). Chronic dehydration on Antarctica rarely develops unless the fuel supplies necessary to melt ice run low,
but this problem did confront Scott’s party (108, p. 188)
who, on the return journey from the Pole, repeatedly discovered cans of stored oil close to empty due to fuel seepage
(35, 96, p. 175). Almost certainly, at least on the return
journey, Scott’s party suffered not only from chronic dehydration but also increased energetic costs to defend against
hypothermia due to the consumption of ice.
V. VITAMIN C
There was no concept of micronutrients such as vitamins at
the turn of the century, and thus no understanding that a
chronic lack of vitamins could manifest in diseases such as
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opposed to the progressive use of protein stores for energy,
and in situations of chronic exercise coupled with a diet
deficient in calories, standard protein intakes may be inadequate (36). Also, thermogenesis values for protein are as
high as 20 –30%, compared with 0 –3% for fat and 5–10%
for carbohydrate (120), so the extra heat created by assimilating protein may be advantageous during cold days and
particularly during cold nights, although disadvantageous
in that it represents a raising of metabolic rate. Even less
clear is whether being on the plateau, which is at altitude,
causes an increase in the proportion of endogenous energy
obtained from muscles (57). This is perhaps at least in part
to meet an increased requirement by the body for the amino
acid glycine (104) because of its involvement in hemoglobin
production. Given all this uncertainty, it is a valuable fact
that Stroud and Fiennes, who experienced very negative
energy balances, maintained normal plasma albumin levels
throughout their journey, suggesting that protein synthesis
remained adequate (117). In reality, it is the presence of
sufficient carbohydrate that tends to protect protein stores
from the demands for gluconeogenesis during exercise-induced hypoglycemia (65, 109). Furthermore, protein consumed at high levels (above ⬃2.0 –2.5 g/kg body mass per
day, i.e., above ⬃150 g per day for a typical man-hauler)
may have unwanted effects on health due to the toxicity of
hyperammonemia and hyperaminoacidemia (11, 24), especially as periods of consistently heavy exercise increase levels of free amino acids due to enhanced muscle breakdown.
THE PHYSIOLOGICAL DEMANDS OF ANTARCTICA
Modern knowledge of the function of vitamin C is extensive. Ascorbate is an ion of vitamin C necessary for essential
metabolic reactions, most relevantly including collagen synthesis. Thus vitamin C is vital for the growth and repair of
body tissues including generating skin, scar tissue, and ten-
dons. Most organisms synthesize vitamin C from glucose
but, apart from a few exceptions such as bats and guinea
pigs, most mammals including humans are reliant on gaining vitamin C by ingesting it. Humans require ⬃10 mg/day
to avoid scurvy (100), and only since the 1930s has vitamin
C been synthesized for consumption in pills or artificial
supplementation of foodstuffs.
Whether Scott or any of his four men who reached the Pole
actually suffered from scurvy is unclear. Wilson, who was a
member of the polar party and also the expedition’s observant physician, did not suggest in his diaries that he thought
scurvy was present, although he was evidently prepared to
report it when diagnosed based on his diaries during a previous Antarctic expedition (108). However, Evans did show
signs of poor wound repair even before the team had left the
polar plateau (106, entried 23rd, 24th, 30th January 1912).
His nose was blistered and starting to rot, and at one point
he dislodged two finger nails. A hand wound suffered during an accident many weeks before was also suppurating.
Wilson may have attributed such limited recovery from injury to the low temperatures, which are known to slow
wound repair probably due to the peripheral vasoconstriction of blood vessels. Nonetheless, Evans was perhaps the
member of the five-man party most likely to suffer scurvy
since he was a fussy eater adverse to eating raw meats (35)
and at the point of his death, he had probably ingested little
vitamin C for months. The longest the body can store ascorbic acid is ⬃12 wk (74), the time that scurvy becomes manifest on a diet devoid of vitamin C (52) and about the time
into the journey that Evans’ wounds became more obvious,
though serious symptoms are not expected for another couple of weeks (108). In contrast, today’s long-distance Antarctic adventurers never suffer scurvy as they consume fortified freeze-dried meat, often with vegetables (FIG. 6) and
multivitamin tablets (111).
VI. SLEEP
The duration and quality of sleep experienced by Antarctic
travellers is affected by their comfort during rest periods,
which in turn is affected by temperature, the dryness of their
clothes and sleeping bags, and satiation (93). Sleep is also
disrupted by frequent awakening at night, typically to a
feeling of air hunger, an unpleasant situation experienced
by Fiennes close to the South Pole (35). While waking to air
hunger was medically recognized in the 19th century and
named Cheyne-Stokes respiration (oscillations in ventilation including periodic apnea), its occurrence in man-haulers is now thought to usually be due to different reasons
than those in seriously ill patients. Man-haulers typically
experience air hunger because of a build-up of carbon dioxide when faces are turned into sleeping bags for warmth,
and this is exacerbated at altitude on the polar plateau by
the tachypneic response to hypoxia (106, entry 3rd February 1912).
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rickets or pellagra (vitamins D and B3, respectively). However, unknowingly, these vitamins were generally present in
the necessarily limited diets of sailors (8) and explorers.
More problematic was the risk of scurvy. Since James Lind’s
Treatise on Scurvy published in 1753, there was a fairly
rapid and general acceptance that acidic fruits such as lemons and limes were a valuable addition to ship stores.
Lemon juice was consumed on board James Ross’ south
Polar expedition 1839 –1843. By the turn of the 20th century, ideas about diets to stave off scurvy had broadened,
with links made between the occurrence of symptoms including sore gums, bruised legs, suppurating wounds, and
loss of teeth, with a dietary deficiency of fruit and vegetables
(96, p. 59). It was also believed that fresh meat was prophylactic against scurvy (108) and known that people indigenous to the Arctic ate almost no plants yet avoided the
disease. Nevertheless, in Scott’s time, the consumption of
citrus juices had fallen into disrepute (100), and for Polar
explorers on a diet of restricted variety, there was a distinct
lack of clarity about the best selection of Antarctic-suitable
foods to include in rations (135). Clouded understanding
was further confused by a number of hypotheses proposed
by scientists (e.g., Refs. 4, 136) as to the cause of scurvy,
including the possibility that some foods were scorbutic (6,
67, 106, entry 18th August 1911), and not until work on
guinea pigs by Chick and Hume (22) was it widely conceded
that lime juice supplied to the navy at that time had virtually
no antiscorbutic value. A wide range of vegetables, jams,
and bottled fruits were available to Scott’s men, along with
freshly killed seal meat, while on the base at Cape Evans
(72) prior to their assault on the Pole. We now know these
foods probably provided at least 20 mg of vitamin C per
day, sufficient to prevent scurvy (108). This diet gave Scott
hope, sometimes even confidence, that scurvy would be
avoided during the Southern journey (106, entry 26th May
1911). Furthermore, despite eating only preserved foods
(e.g., Ref. 106, entry 6th August 1911), since fruit and
vegetables were not suitable for Antarctic sledging due to
their bulk and likely bacterial contamination following defrosting on warmer days, scurvy had apparently been
avoided during Shackleton’s aforementioned expedition
that had got close to the pole (76) and also during the
aforementioned trip by the Crozier party. However, unbeknownst to Scott, it was likely only the pony meat supplementing his sledging rations that provided a small supply of
vitamin C (a few milligrams per person per day eaten)
(100), especially as with rationing of cooking fuel the polar
party ate at least some of this meat semi-raw (21) and thus
did not cause so much decomposition of the vitamins or
cause them to leach into the cooking water (2, 101).
LEWIS G. HALSEY AND MIKE A. STROUD
A. Physiological and Psychological Effects of
Sleep Deprivation
A. Altitude Sickness
Although the average altitude of the polar plateau is only
2,300 m, in terms of oxygen partial pressures the average
effective altitude is ⬃2,800 m. There are two proposed
explanations for this: 1) the extreme cold reduces the height
of the troposphere, increasing the rate at which atmospheric
pressure decreases with altitude (130); and 2) the wind circulating around the continent creates a vortex lowering the
pressure (108) (FIG. 7). The partial pressure of inspired oxygen at the edge of the Antarctic is only slightly less than 1
atmosphere (760 mmHg), but on the plateau, it averages
⬃0.7 atmospheres (⬃510 mmHg) (130), with oxygen availability reduced by 30%. This initiates both short- and longterm responses that enhance oxygen availability (37). Rapid
accommodation through increased ventilation raises oxygen delivery and increases the affinity of hemoglobin for
oxygen via respiratory alkalosis, although the latter is offset
by renal elimination of excess base as bicarbonate, resulting
in diuresis. A gradual acclimatization to altitude, through
hypoxia-sensitive gene and protein expression, improves
cellular respiration efficiency, and over tens of days, there is
an increase in hemoglobin concentration (polycythemia) as
a result of a greater production of erythrocytes in combination with a reduction in volume of blood plasma by enhanced excretion of water (and salt) (119). The time taken
for full acclimatization to the plateau is affected by a range
of factors including rate of ascent and altitude reached and
varies considerably between individuals, although the bulk
of acclimatization will have been achieved within a week.
Around the end of the 19th century, to start documenting
the effects of altitude and acclimatization to altitude (16),
VII. THE POLAR PLATEAU
The polar plateau, which includes the South Pole, has a
diameter of ⬃1,000 km and is at high altitude with the
highest point 4,093 m above sea level. For this reason, the
temperatures there are the lowest in Antarctica (averaging
around ⫺25°C in summer) with the harshness of the environment epitomized by the complete absence of vertebrate
species. Thus, as they approach the South Pole, decreased
oxygen availability alongside lower temperatures and
higher winds exacerbate the problems for polar travellers
and trigger new problems such as mild neuropsychological
impairment (15) and altitude sickness. These sometimes
subtle but potentially key phenomena were not appreciated
in Scott’s time for although deleterious effects of altitude on
cognitive function were known about by the end of the 18th
530
FIGURE 7. Effects of altitude on the polar plateau on barometric
pressure and inspired partial pressures of oxygen. The circles represent the mean and maximum altitude of the polar plateau, while
the square represents its mean effective altitude.
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A physiological understanding of the value of sleep to the
body, and the deleterious effects of sleep deprivation, were
rudimentary in Scott’s time, although it was known that a
lack resulted in poorer cognitive and physical performance
(91, 97) and lassitude (4, 106, entry 2nd August 1911). The
stages of sleep were not described until 1937 (70), and
rapid-eye-movement (REM) sleep not for another 20 years
(26). Since then, a huge amount of research has been conducted on people and relevant mammalian models to describe sleep and explain the biological value of each stage
along with problems occurring with deprivation, and it has
become clear that a lack, particularly chronic, impairs both
physiological and psychological function (31, 98). Van
Dongen et al. (126) reported clear cognitive performance
deficits in people exposed to just moderate sleep deprivation
(6 h/day) for 2 weeks, while Tharion et al. (122) measured
a decrease in the marksmanship of soldiers. Furthermore,
for man-haulers already on a starvation diet, insomnia
could represent a crucial energetic expense. Sleep deprivation causes an increase in basal metabolic rate, perhaps due
to increased peripheral vasoconstriction reducing insulation (103), and periods of wakefulness consume more energy than periods of sleep due to increased physiological
arousal (13). Furthermore, rats chronically deprived of
sleep not only exhibit increased basal metabolism (59) resulting in weight loss but also reduced rates of healing (43)
and compromised immunity (33, 139). The increased basal
metabolic rate associated with sleep deprivation in humans
may therefore be a response to infectious processes (32).
Scott’s party suffered from chronic partial sleep deprivation, at least because they often slept purposefully for only
a few hours to increase time man-hauling (e.g., Ref. 106,
15th February 1912); perhaps Evans would have experienced less extensive deterioration of his hand wound and
emotional state (106, entry 30th January 1912) had he
gained more sleep.
century (55), it was not until the 1960s that patterns of
neurological impairment at altitude were documented, nor
was it was realized that there is deterioration in visual acuity (81).
THE PHYSIOLOGICAL DEMANDS OF ANTARCTICA
The Amundsen-Scott research station was built at the Pole
in 1956 at an altitude of 2,771 m, with an effective altitude
of 3,350 m. The medical clinic at the station typically records many cases of altitude sickness every year (http://www.
antarcticconnection.com/antarctic/news/2006/110706mayo.
shtml), with ⬃1 in 50 people suffering chronic mountain
sickness severely enough to need evacuation to sea level
(35). Chronic mountain sickness, sometimes known as
Monge’s disease (84), has outward symptoms including
headaches, tinnitus and, perhaps most pertinently for
man-haulers, fatigue, breathlessness, and sleeplessness,
with these symptoms exacerbated by dehydration since it
causes similar problems. In extreme cases, residents at
the station experience cerebral edema or pulmonary
edema, although the majority of modern visitors to the
Amundsen-Scott station fly there from the edge of Antarctica at sea level, and so experience a step change in
oxygen availability (130). In contrast, man-haulers venturing onto the polar plateau take many days to climb to
it; for example, Scott spent around 12 days ascending to
the plateau via the Beardmore Glacier, to an elevation of
2,700 m (108). This represents a slow rate of ascent and
so on reaching the plateau he would have enjoyed valuable physiological acclimatization. Furthermore, as altitude increases up to 3,500 m, the oxygen content of
blood falls slowly because the slope of the sigmoidshaped oxygen dissociation curve is shallow up to arterial concentrations associated with this height (0.08 atmospheres; 60 mmHg). This is perhaps reflected by the
fact that over 100 million people permanently live between 3,000 and 5,000 m in the Andes where they often
undertake labor-intensive work (94).
Nevertheless, due to the great exertion required to manhaul, the effects of altitude are intensified. Evidence of altitude sickness is present not only in the diaries of Scott and
his party during their more than 50-day stay on the plateau,
but also from those of Roald Amundsen, whose team noted
fatigue from the low oxygen levels and had difficulty sleeping while on the polar plateau to and from the South Pole
(35, 96); Ernest Shackleton, whose men reported severe
headaches and nosebleeds (see also 76); and more recently
from Fiennes and Stroud (114).
B. Weight Loss at Altitude
In contrast to today, in 1911 there was no information to
suggest that altitude might further augment rates of body
weight loss from man-hauling, a phenomenon which could
clearly be dangerous to Antarctic explorers even if it might
possibly represent a beneficial adaptation to help reduce
oxygen requirements (Denny Levett, personal communication). However, although reductions in body mass at altitude are now well documented, the associated mechanisms
remain unclear. While mountaineers typically exhibit a reduced appetite (124) and quicker perception of satiety (133)
(Scott reported on the plateau that the rations “continue to
amply satisfy”; 106, entry 7th January 1912) resulting in a
lower calorie intake, they can sometimes also exhibit increased levels of activity and be exposed to lower temperatures and stronger winds, resulting in a higher energy expenditure. Furthermore, hypobaric hypoxia possibly also
results in increased energy expenditure through an increase
in basal metabolism (86) during the first days at high altitude, although this then decreases, plateauing at or slightly
above normal levels (78, 86). Exposure to the cold and
altitude together may increase metabolic rate due to a reduction in peripheral vasoconstriction (23). Another possible reason for an elevation in metabolic rate at altitude
could be due to thyroid upregulation in response to cold
(86), increased respiratory effort, and/or increased sympathetic drive (78), and it is not even clear as to whether this
effect is directly due to low oxygen levels or effects of cold
(46). Explorers at altitude may also experience reduced gastrointestinal function from hypoxia that results in delayed
gastric emptying and decreased intestinal absorption, although there is little empirical evidence for this below very
high altitudes (57). While it might seem unlikely that a loss
of appetite on the polar plateau affected Scott’s party since
their rations were typically grossly insufficient to supply
their daily energy expenditure, this possibility cannot be
ruled out as it is unknown whether the onset of satiation at
altitude is affected by rates of energy expenditure. Scott and
Wilson were unable to finish their special Christmas Day
meal while on the plateau, despite expending the energy to
average 15 miles a day on an upward gradient (35; see also
Ref. 106, entry 13th December 1911), although another
explanation for their suppressed appetite could be a response to the very high protein content of their rations.
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Paul Bert (10) and others undertook laboratory experiments (44) and field experiments in places such as Morococha and Monte Rosa (140). For example, Bert and Nathan
Zuntz demonstrated in animals that it was a reduction in
partial pressure of oxygen that typically caused illness or
even death at altitude and that high-altitude acclimatization
is associated with polycythemia (131). Thus, by the time the
polar plateau was discovered during the 1901–1904 Discovery expedition to the Antarctic, it was known that as
polar explorers ventured closer to the South Pole, lower
oxygen levels could result in deleterious effects. However,
the majority of understanding about human physiology at
altitude has been gained only in the past half-century, starting with the “Silver Hut” expedition in 1960 on Mount
Everest (131), and importantly, some of the more severe
effects that result from pulmonary edema were not recognized until well after Scott’s time (53), even though the
presence of edema was documented long before (132). Thus
Scott did not know that along with a range of relatively
minor negative effects his team could in fact suffer seriously
debilitating problems on the polar plateau due to its altitude.
LEWIS G. HALSEY AND MIKE A. STROUD
VIII. COULD SCOTT HAVE SURVIVED?
The major factor that continues to make long man-hauling
expeditions in Antarctica extremely physiologically demanding is the inevitable starvation diet. The metabolic
requirements of sledging at very low temperatures do not
usually represent major physiological risks in themselves
(38) but unavoidably become highly detrimental over time
since they demand energy expenditures that cannot be fuelled by the food rations it is possible to haul, even if supplemented by depot stores. Other factors such as high altitude and sleep deprivation then have additional damaging
effects once loss of body mass has weakened physiological
integrity (e.g., Ref. 138).
Table 1 A summary of the negative effects, mainly physiological, caused by chronic man-hauling in the Antarctic, including the
degree of debilitation that they have tended to cause early explorers and modern-day adventurers
Factor
Cold
Emaciation
Vitamin deficiency
Dehydration†
Sleep deprivation
Altitude
Major Potential Effects
Increased metabolic rate; thus increased weight loss
Frost bite
Increased sensitivity to cold-induced effects
Decreased physical strength
Reduced tissue regeneration
Higher risk of exercise-induced injury
Suppurating wounds
Decreased physical strength and stamina
Decreased general cognitive performance
Increased energy expenditure
Compromised immune system and reduced tissue repair
Poorer concentration, vigilance and decision making
Headaches
Tiredness
Increased metabolic rate; thus increased weight loss
Early Explorers
Modern-Day Adventurers
***
**
*****
****
***
**
*
**
*
*
*
Asterisks denote degree of debilitation; five ⫽ highest.†Note that dehydration was probably more debilitating for
Scott and his men during the latter part of their journey than was typically the case for early Antarctic explorers during their journeys in general.
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FIGURE 8. The energetics associated with Scott’s expedition to the South Pole. The full lines represent
estimated energy expended per man (black) and estimated energy consumed from rations supplemented with
pony meat (gray). The area between these lines represents the energy (calorie) deficit. The stippled line
indicates the estimated change in body mass of the men (given a mean starting mass of nearly 77 kg; Ref. 100)
as a consequence of this deficit. The crosses denote the time into the trip that the deaths of the party occurred.
Calorie intake during the last six or so weeks of the lives of the final party members is difficult to estimate due
to more limited documentation, and while greater rations per man became available as group members died,
fuel supplies available to heat those rations gradually diminished (108). [Adapted from Piantadosi (94), by
permission of Oxford University Press.]
THE PHYSIOLOGICAL DEMANDS OF ANTARCTICA
Clearly, the physiological effects of heavy, chronic exercise
while on limited rations in the low temperatures of Antarctica are now much better understood than in Scott’s time
(see TABLE 1 for a summary) but even so, technology
aside, there is a perhaps surprisingly limited amount that
can be done differently. The single key difference in the
physiological management by today’s long-distance Antarctic traveller centers on the rations consumed. Around
700 kcal more per 24 h are ingested while the macronutrient proportions now favor fat and carbohydrate over
protein, reducing rates of physical wasting and degradation in performance. The modern rations also include
micronutrients in abundance, and present-day explorers
aim to commence their journeys with heightened body
mass even though this can prove difficult if they are manhaul training prior to the event (115).
Since Scott and his last two companions, Wilson and Bowers, faltered on their return journey just 11 miles from the
next depot, it seems reasonable to conclude that augmented
rations based on modern physiological wisdom would have
kept them alive, albeit that it would probably have been
hard fought for. Most importantly, they would have had
more strength because of larger muscles, more insulation
due to greater fat deposits, and a greater ability to recover
and heal after each period of man-hauling due to adequate
vitamin levels in the body. However, whether this would
have been sufficient to make the difference for Evans and
Lawrence Oates, who died earlier in the journey, is less
clear, particularly since Evans fell ⬃250 miles earlier than
did Scott and sledge-pulled particularly hard (106, entry
14th December 1911). Arguably, therefore, without a diet
considerably higher in calories and vitamin C, neither being
an option for Scott, Evans’ fate was always out of their
hands. Thus present physiological understanding may not
be sufficient to protect everyone on man-hauling expeditions across the Antarctic.
As with the highest mountain in the world, Mount Everest,
where altitude and latitude conspire to make summiting
only just possible by an unaided person, the return journey
to the South Pole from the Antarctic coast is only just within
reach for the most capable of people. The four-month summer window each year, during which man-haulers must
inevitably pull insufficient food in environmental conditions that conspire to induce rapid wasting, today still represents an enormous, potentially life-threatening physiological challenge (108, 114). In the case of both climbing Everest and reaching the South Pole, technological advancements can
now compensate certain limitations of the human condition; however, other weaknesses remain as restricting factors whose capacities must be stretched to a dangerous degree if these feats are to be achieved.
ACKNOWLEDGMENTS
We thank Peter Clarkson, Adrian McCallum, Denis
Wilkins, Tom Davies, Ben Edwards, Mark Hines, Isabella
Capellini, and Chris Tyler for their comments on drafts of
the essay, and for discussions about the subject with Jon
Green. Alex Hibbert kindly provided a photo of the food
types in his sledging rations. A special thank you goes to
Heather Lane at the Scott Polar Research Institute for her
support during this project.
Address for reprint requests and other correspondence: L. G.
Halsey, University of Roehampton, Holybourne Ave., London SW15 4JD, UK (e-mail: [email protected]).
DISCLOSURES
No conflicts of interest, financial or otherwise, are declared
by the authors.
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