How Exercise Affects Your Heart

Cardiovascular diseases (CVDs) are the number one killer in the United States.

What is worse is that despite the many guidelines and risk factors released by the American Heart Association (AHA) and the World Health Organization (WHO), Americans continue to engage in high-risk activities for CVDs. Such high risks activities include sedentary lifestyles, unhealthy diets, smoking, and alarming levels of stress.

A regular exercise routine is good for heart health. Moreover, it reduces the risk of CVDs like myocardial infarction (MI), and coronary heart disease (CHD). Exercise helps regulate nerve activity in the body which has a tremendous effect on blood pressure and overall heart health.

The Heart:

The heart is the organ responsible for pumping blood to different parts of the body. Four distinct chambers make up this pumping organ. They work in relation to each other to oxygenate the blood and deliver it where needed.

The heart connects to the vascular system, which consists of a network of blood vessels that integrate throughout the body. This network of blood vessels helps to deliver oxygen and nutrients to distant organs and tissues in the body.

From its first beat during fetal life, until the moment we die, the heart never stops or rests. It is therefore important to take great consideration of this amazing organ, whose very function has been the symbol of life throughout human history.


The Heart During Exercise:

Exercise stimulates the sympathetic nervous system, which is most associated with the fight-or-flight (or stress) response. Sympathetic nerve networks integrate a variety of smooth muscles, hormonal glands, and cardiac muscle.

Thus, the onset of exercise will stimulate sympathetic nerves innervating the heart leading to an increase in heart rate (1). The adrenal glands, which sympathetic nerve activity also stimulates, release epinephrine (adrenaline) into circulation and contributes to heart rate elevation.

An elevated heart rate helps supply working muscles with oxygen and nutrients necessary to exercise. Sympathetic nerve activity also redirects much of the blood flow away from organs like the kidneys and liver, leaving more blood for the working muscles. Blood vessels delivering blood to visceral organs, for example, constrict while those delivering blood to the working muscle dilates.

Exercise poses many benefits for cardiovascular health including weight control, lower blood pressure, and better athletic performance.


Body Weight:

Metabolic diseases and excess weight itself both represent risks for cardiovascular disorders. Routine exercise helps control body weight which is also beneficial for the prevention and control of metabolic diseases like type 2 diabetes.

During exercise, the skeletal muscle helps consume excess glucose in circulation to fuel physical activity, which helps regulate blood glucose levels. Circulating fatty acids are also consumed during exercise; thus an exercise routine will also help regulate circulating glucose and fatty acids.


Blood Pressure:

Regular exercise helps lower resting heart rate as well as blood pressure. High blood pressure is a key player in cardiovascular pathology and it is a leading cause of CVDs. High blood pressure can lead to micro-tears in the vascular endothelium (the inside of blood vessels), which is followed by cholesterol deposition and subsequent inflammatory response. The repair of such micro-tears leads to a buildup of plaques throughout circulation and hardening of blood vessels. Such hardening and narrowing of blood vessels are considered obstructions themselves and also contribute to high blood pressure.

The hardening of blood vessels is known as arteriosclerosis and the narrowing of the vascular passage is known as atherosclerosis. Both arteriosclerosis and atherosclerosis (a type of arteriosclerosis) are major causes of CVDs including myocardial infarction (a heart attack), coronary heart disease, cardiomyopathy, and sudden cardiac death.

Athletic Performance:

Routine exercise is beneficial to athletic performance. Cardiovascular training adaptation in response to routine exercise includes an increase in maximal stroke volume and more effective use of circulating oxygen.

The stroke volume of the heart refers to the amount of blood pumped into systemic circulation in a single contraction of the left ventricle. In fact, this increase in stroke volume is due to the increased effectiveness of the left ventricle in response to exercise.

Oxygen consumption is also more effective in response to exercise. Training adaptations in response to endurance exercise, for example, result in a greater number of muscle fibers high in mitochondria. This is significant because it means that the body has learned to use oxygen more effectively via aerobic (oxygen-based) pathways. These pathways produce higher levels of ATP than lactic acid fermentation to fuel the working muscles.

Both of these training adaptations pertaining to cardiovascular function enhance athletic performance and reduce the risk for cardiovascular diseases.

Any high-intensity exercise regimen will stimulate and improve your cardiovascular system. If you want to improve your heart health, stop by Santa Cruz CORE to sign up for a session of personal training, semi-private training, or even Vasper!


“Science of Exercise.” Coursera, University of Colorado Boulder,