THE EFFECT OF POSTURAL POSITION ON
RESPIRATORY FLOW AND VENTILATION
WHILE TREADING WATER
Allyssa Analytis
Advisor: Dr. Laura Malloy
BIG PICTURE
 Extremely relevant to my sport and will directly help me in real
life situations.
 Water polo requires a quick transition between body positions:
 Horizontal (Prone)
vs.
Vertical (Upright)
BACKGROUND LITERATURE
 Pederson et al 1996:
 8 highly trained cyclists exercised to exhaustion.
 Conclusions:VO2 max was higher in the upright position.
 Sheldahl et al 1987:
 Investigated if head-out water immersion exercise had an effect on
cardiorespiratory response.
 Subjects cycled at 40, 60, and 80% of maximal oxygen consumption in upright
position on land and in the water.
 Conclusions: Heart rate was significantly lower at 80% VO2 max in the water.
 Cardiac output must be maintained at a higher level in the water.
 Respiration rate was higher in the water.
POSTURE ISSUES IN THE WATER
 Treading water in different positions can bend the respiratory system.
 Changes the resistance in the respiratory passages.
 Increased resistance in the chest while under water increases the effort
required of the respiratory muscles.
 Prone and upright positions each change the work of breathing caused
by pressure on the chest.
 Air flow
 Oxygen consumption (VO₂)
IMPORTANT VARIABLES & EQUATIONS
 Respiration Rate (RR)
 # breaths / minute
 Tidal Volume (TV)
 L / breath
 Ventilation = RR x TV
 L / minute
 V = I R (Ohm’s Law)
 R =V / I
 Airway Resistance (R) = Airway Pressure (V)
Airway Flow (I)
 Airway Pressure
∝ TV
 Airway Resistance ∝ TV
Flow
(Index of Resistance)
Main questions: Which variable is responsible for changes in ventilation?
And how does that relate to oxygen consumption?
Could resistance changes be responsible for changes in ventilation?
And how does that related to oxygen consumption?
MY HYPOTHESIS
 Postural position will affect VO₂ and ventilation while treading
water.
 My assumption: Postures that induce the greatest RR will be the
ones that results in greater VO₂.
 Postures that increase airway resistance will result in greater
VO₂.
 Test will be done by measuring how TV, RR, VO₂, and airway
resistance will differ from posture to posture across different
intensities.
MATERIALS AND METHODS
 10 members of the Hartwick women’s water polo team were tested.
 Each subject signed a consent form prior to participation.
 2 way anova with repeated measures.
 Each individual was tested at every position for every intensity on 2
different days.
Posture 1:
Upright
Easy
Medium (60% of
max heart rate)
Hard (80% of
max heart rate)
*Heart rate was measured in
order to verify exercise intensity.
Posture 2:
Prone
APPARATUS
In the lab:
On the pool deck:
LABSCRIBE SOFTWARE
RESULTS
Respiration Rate
Tidal Volume
35
0.6
0.5
25
20
Prone
15
Upright
10
Tidal Volume (L/breath)
Respiration Rate (breaths/min)
30
0.4
0.3
Prone
Upright
0.2
0.1
5
0
0
Easy
Medium
Hard
Intensity
P-values: a) Orientation = .001
b) Intensity = .000
• Prone
posture induced the higher RR.
•Upright posture induced the higher TV.
Easy
Medium
Hard
Intensity
P-values: a) Orientation = .021
b) Intensity = .002
Ventilation
16
14
Results:
higher ventilation.
Ventilation (L/min)
• Upright posture induced
12
P-values: a) Orientation = .021
b) Intensity = .004
10
8
Prone
Upright
6
4
2
0
Easy
Medium
Intensity
Hard
Relative Oxygen Consumption
20
18
Results:
greater relative VO₂ for a given
heart rate.
Relative VO2 (mL/kg/min)
• Upright position induced the
16
P-values: a) Orientation = .009
b) Intensity = .000
14
12
10
Prone
Upright
8
6
4
2
0
Easy
Medium
Intensity
Hard
CONCLUSIONS
 In upright position, one breathes deeper (inhales more O₂ per breath).
 More efficient ventilation to alveoli.
 In prone position, one breathes faster in order to meet respiratory
demands.
 Could be caused by increased in resistance in chest.
 Bending of the respiratory passages could cause respiratory restrictions.
 Not as efficient; works respiratory muscles more.
 RR is not responsible for a larger VO2. Instead, TV is more important.
 Overall, upright position is more energetically efficient.
CITATIONS
 Albert, R. K., and R. D. Hubmayr. 2000. The Prone Position Eliminates Compression of the
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Lungs by the Heart. American Respiratory Critical Care Medicine 161(5): 1660-1665.
Hughson, R. L., J. E. Cochrane, and G. C. Butler.1993. Faster O₂ uptake kinetics at onset of
supine exercise with than lower body negative pressure.
Hughson, R. L., H. C. Xing, C. Borkhoff, and G. C. Butler. 1991. Kinetics of ventilation and
gas exchange during supine and upright cycling exercise. European J Applied Physiology
Occupational Physiology 63(3-4): 300-307.
Koga, S., T. Shiojiri, M. Shibasaki, N. Kondo, Y. Fukuba, and T. J. Barstow. 1999. Kinetics of
oxygen uptake during supine and upright heavy exercise. The American Physiological
Society 253-259.
MacDonald, M. J., J. K. Shoemaker, M. E. Tschakovsky, and R. L. Hughson.1998. Alveolar
oxygen uptake and femoral artery blood flow dynamics in upright and supine leg exercise
in humans. The American Physiological Society 1622-1628.
Pederson, P.K., H. Mandoe, K. Jensen, C. Anderson, and K. Madsen. 1996. Reduced arterial
O2 saturation during supine exercise in highly trained cyclists. Acta Physiologica
Scandinavica 158(4): 325-331.
Sheldahl, L. M., F. E. Tristani, P. S. Clifford, C. V. Hiughes, K. A. Sobocinski, and R. D. Morris.
1987. Effect of Head-Out Water Immersion on Cardiorespiratory Response to Dynamic
Exercise. Journal of the American College of Cardiology 10(6): 1254-1258.
Zhu, M, W. Zhang, J.-N. Wang, H. Yan,Y.-K. Li, B. Al, S.-L. Fu, and X.-N. Fu. 2009. Upright
position mechanical ventilation: An alternative strategy for ALI/ARDS patients? Medical
Hypotheses 73(5): 821-823.