Heart-related health conditions are among the top causes of death in the world. Exercise is proposed as one of the methods by which heart health can be improved. Despite this, the relationship between exercise and the heart is not fully understood.
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How exercise helps the heart
Several longitudinal studies have investigated how exercise and the heart or cardiovascular system as a whole work together. Exercise is associated with reduced mortality and a slight increase in life expectancy. Similarly, heart fitness level is associated with lower death rates. This stays true even in the face of confounding factors such as smoking.
While the beneficial link between exercise and the heart has been repeatedly established, how this works is less clear. One theory is that exercise influences the levels of lipoproteins circulating in the blood. Because lipids in the blood are central to the risk of cardiovascular disease, their modulation can be beneficial for heart health.
Another theory by which exercise affects the heart is by modulating blood pressure. While an individual is exercising, the heart increases its rate and the stroke volume, leading to a mean increase in blood pressure. Long-term exercise leads to a net reduction in blood pressure when resting, because the heart becomes more efficient, which in turn reduces the risk of cardiovascular disease development.
The heart rate and blood pressure are controlled by the sympathetic nervous system. More long-term studies are finding that exercise can help the sympathetic nervous system be less reactive, which leads to increased heart rate variability and thereby lower risk of cardiac arrest.
Lastly, changes in heart shape can be another reason exercise influences heart health. Because of the different types of pressure the heart experiences during exercise, there will often be changes in mass in different areas of the heart, such as increases in chamber wall thickness. This may, in turn, reduce the risk of a heart attack.
Useful types of exercise
The general advice is that all types of exercise are beneficial and encouraged. While endurance exercise is important, such as swimming and playing sports, adding in muscle-strengthening exercise is also encouraged. Everyday activities, such as cleaning and walking, are also sources of activity that almost everyone does or can do.
People are advised to get 150 minutes of moderate-intensity exercise per week, but this can be modified in the case of certain health problems. Moderate-intensity exercise is defined as an activity that makes a person warmer, breathe harder, and increase heart rate, but it should not be difficult enough that a conversation cannot be carried out.
One recommendation for getting this right is the Talk Test, wherein you attempt to speak or sing. If singing is possible, the exercise is too light. If speaking is not possible, the exercise is too hard.
For the most possible protection, the recommended amount of exercise is increased to 30 minutes of moderate exercise each day. This allows for the heart to reach a level at which metabolic pathways are activated, which fortifies the heart towards potential damage.
Most Americans do not engage in this level of activity, but even short bursts of exercise a day can decrease the mortality risk. Too much exercise, at 3 times the recommended levels, can actually increase coronary artery calcification and therefore reduce heart health.
Further Reading
Extra hour of weekly exercise reduces risk of atrial fibrillation