Why Resting Heart Rate Is Important
for Health
Heart rate — the number of times the heart beats per minute — would seem to
be an obvious variable in health and longevity, especially as it concerns
heart disease. True to intuition, it turns out that resting heart rate is
important for health.
What resting heart rate means
Resting heart rate (RHR) can be compared to VO2max, in that they both measure
a parameter that itself has many facets. RHR measures not just the integrity
and health of the heart, but the overall health of the blood and the tissues
it oxygenates, as well as the nervous and hormonal systems, which play
important roles in setting heart rate.
A good deal of research has looked into the association between RHR and
cardiovascular disease — which is the leading cause of death in the U.S. —
and also the association with total death rates.
In all cases, the research has found that
a low resting heart rate means a low death rate
a high resting heart rate means a high death rate
Associations don’t get much easier than this for a test that you can do
yourself at home, no expense or doctor’s order required.
Since there’s an abundance of research in this area, let’s just look at one
recent study: “Elevated resting heart rate is an independent risk factor for
cardiovascular disease in healthy men and women”.[1. Cooney, Marie Therese,
et al. “Elevated resting heart rate is an independent risk factor for
cardiovascular disease in healthy men and women.” American heart journal
159.4 (2010): 612-619.]
The study was done in Finland. The Finns take a keen interest in heart
disease because their country had at one time the world’s highest rate of
heart disease.
The subject population consisted of 10, 519 men and 11.334 women, more than
enough to generate solid data. Follow-up time for any individual in the study
ranged from 6 to 27 years from the time that RHR was measured. Median followup time was 12 years.
Subjects who had a previous heart attack, were being treated for high blood
pressure, or had heart failure or angina (chest pain) were excluded, so the
study was looking at people who showed no signs of heart disease.
When grouped into quintiles (fifths) of resting heart rate, the results
for
RHR vs cardiovascular mortality looked like this:
Keep in mind here that each quintile contains exactly 1/5 of the group, e.g.
1/5 of all men and women had a resting heart rate >82, and only 1/5 had one
of <60.
Men in the highest quintile had nearly four times the rate of death from
cardiovascular causes as the lowest quintile, and for women about three
times.
Next, take a look at the chart for total mortality, that is, death from all
causes, not just cardiovascular disease. The same relation holds: the higher
the resting heart rate, the greater risk of death.
For men, those with RHR >82 had about three times the death rate as those
with RHR <60. For women, the same relation was about double.
These results were attenuated somewhat after the researchers adjusted their
stats for waist size, smoking, blood pressure, diabetes, and physical
activity, but remained highly significant, with total mortality increasing
about 20% for each increase in RHR of 15 beats per minute, for both men and
women.
Why resting heart rate affects health
The researchers comment:
The mechanism through which elevated RHR exerts its deleterious
effect is unknown. Possibilities include predisposing to ischemia,
arrhythmia, and plaque rupture or by promoting atherogenesis by
increasing the absolute number of sheer stresses to which the
vessel wall is exposed. Our demonstration of the stronger effect on
fatal than nonfatal events supports proarrhythmogenicity as one of
the mechanisms, as do previous studies showing a particularly
strong effect of elevated RHR on sudden cardiac death. [Link added]
Curiously, although RHR is perhaps most strongly affected by one’s level of
physical fitness, the association between RHR and death rates persisted even
after adjusting for physical activity.
How to measure your resting heart rate
You can easily measure your resting heart rate.
First, find your pulse, either at your wrist or neck. Count the number of
beats in 30 seconds, then multiply by two. This is best done in the morning
in a calm state. If you take it at work or within a few hours after exercise,
the reading likely won’t be accurate.
I took my RHR yesterday, and it was 46, putting me solidly in the lowest
quintile. I wonder whether if the researchers had made their results more
finely grained, and broke out the results for, say, those with RHR <50,
whether risk would be even lower. My guess is that it would, since all the
results in the study were graded, that is, for each rising quintile of RHR,
death rates were higher.
In a chart showing what each level of RHR represents, my RHR falls into the
category of “athlete” above “excellent”. (note that this chart doesn’t have
any scientific references, so take that at face value — or not.)
An article at National Geographic says that a well-trained endurance athlete
has a RHR of 40, and that Miguel Indurain, a five-time Tour de France winner,
had a RHR of 28.
Back when I used to run long distance, I recorded a RHR of 32.
How to lower your resting heart rate
Besides obvious factors like losing fat and not smoking, the most important
way to lower resting heart rate is through exercise.
While endurance exercise may be on record as producing the best results, to
my knowledge, other exercise modalities haven’t been look at. For example,
what is the Olympic sprinter Usain Bolt’s resting heart rate? Or that of an
Olympic weightlifter? my guess is that they are all quite low.
Also, as we’ve previously seen, resistance training, especially when done at
high intensity, produces an increase in VO2max, so that works too.
High-intensity interval training is also good for lowering RHR.
The key for lowering RHR is, just as for anything you want to improve,
putting a stress on the body. Therefore, exercises like walking, while a
healthy pursuit, may not do much to lower RHR; they simply don’t proviode
enough stress to the system.
If you don’t already exercise, and want to undertake a program of RHRlowering exercise, you should get a doctor’s clearance first, especially if
you’re older and/or have pre-existing illnesses.
PS: For more on the best exercise, see my book Muscle Up, and for
more on anti-aging, see my book Stop the Clock.
PPS: Check out my Supplements Buying Guide for Men.