Aerobic Exercise and Heart Health

Aerobic Exercise and Heart Health
by Blake Hagen

Improved Heart Efficiency

Heart efficiency and cardiovascular fitness can be determined by several different
methods. One method is to measure an individual's resting heart rate. A lower
resting heart rate after a period of aerobic exercise training indicates improved heart
efficiency. The stroke volume (amount of blood ejected by the heart each beat) is
increased and this essentially means the heart muscle does not have to pump as
many times to get sufficient blood to the body. With aerobic exercise training, the
heart muscle is strengthened and it does not have to work as hard as it did before
the aerobic exercise training.

For example, at rest, an untrained individual may have a heart rate of 70 beats per
minute (bpm) and a stroke volume of 71 ml/beat. This is equal to a cardiac output of
approximately 5000 ml/minute. On the other hand, an aerobically trained individual
with the same cardiac output will have a resting heart rate of 50 bpm and a stroke
volume of 100 ml/beat.[1] The trained individual is able to get enough blood to his
body with fewer beats than the untrained individual. This demonstrates just one
adaptation the body goes through with regular aerobic exercise training.

Other adaptations that accompany regular aerobic exercise training include an
increased total blood volume, increased blood flow to active muscle, and an increase
in mitochondrial size and density. This increase in mitochondrial density is important
for the use of fat as fuel during sub-maximal aerobic exercise. When a fat molecule is
to be broken down to be used as fuel, it is broken down into a fatty acid and a
glycerol molecule. The fatty acid is transported by the blood to the mitochondria
where it is processed to be used as fuel. With an increase in the number of
mitochondria in the muscle cells, the body can process and use more fatty acids as
fuel. This conserves the potential energy stored as carbohydrate for other uses.[2]
In other words, the body can use fat more efficiently during aerobic exercise and
save the more precious carbohydrate fuel.

Aerobic Exercise and Heart Disease

Regular aerobic exercise can also reduce an individual's lifetime risk of developing
heart disease. A study done at Stanford University found that the best predictor of
death is lack of fitness.[3] Another study done also found that "physical inactivity is
an important risk factor for cardiovascular disease."[4] How fit an individual is plays a
major role in determining how long a lifespan that individual may have. This
improvement in fitness can be achieved through regular aerobic exercise.

Another way that regular aerobic exercise can reduce the development of heart
disease is through an increased number of capillaries in the body. When a person is
aerobically trained, more capillaries develop to improve the oxygen and carbon
dioxide exchange between blood and cells. If an artery is damaged or if blood flow is
blocked, the blood can easily be rerouted to where it needs to get to and deliver the
necessary oxygen. This increased number of capillaries occurs not only in the heart,
but also in the brain and all other parts of the body, thus also reducing the risk of
stroke.[5]

Studies have also shown that regular aerobic exercise may be able to reverse the
effects of heart disease already occurring in an individual. Of all the risk factors
associated with heart disease, many of them are modifiable by regular exercise and
weight control. Risk factors for heart disease which can be reduced or eliminated in
an individual through regular aerobic exercise include hypertension, high levels of fat
in blood, type 2 diabetes, obesity and a sedentary lifestyle. Through regular exercise,
these conditions can improve, and as a result, heart disease can be prevented and in
some cases reversed.[6]

[1] William D. McArdle, Frank I. Katch and Victor L. Katch, Exercise Physiology: Energy, Nutrition, and
Human Performance, 6th ed (Baltimore: Lippincott Williams and Wilkins, 2007): 354.

[2] Ibid., 478-80.

[3] Steven G. Aldana, The Culprit and the Cure: Why Lifestyle is the Culprit Behind America's Poor
Health and How Transforming That Lifestyle Can be the Cure (Mapleton, UT: Maple Mountain Press,
2005), 142.

[4] James B. Carter, Eric W. Banister and Andrew P. Blaber, "Effect of Endurance Exercise on
Autonomic Control of Heart Rate," Sports Medicine 33 (2003): 42.

[5] Aldana, 143.

[6] Philip E. Allsen, Joyce M. Harrison and Barbara Vance, Fitness for Life: An Individualized
Approach, 6th ed (Boston: WCB/McGraw Hill, 1997) 49.

About The Author

Blake Hagen

The evidence suggesting regular
aerobic exercise can reduce the
development of some types of
cancer is solid. Perhaps even stronger
is the evidence suggesting regular
aerobic exercise can have profound
impacts on cardiovascular health.
With regular aerobic exercise, the
heart's efficiency increases, producing
many beneficial effects for the body.
Improved heart efficiency can also
lead to a reduced risk of developing
heart disease.

These statements have not been evaluated by the Food and Drug Administration (FDA). The content on
this website is for educational purposes only. Please consult with your physician before using natural
remedies and before making any drastic changes to your diet or exercise program.