Physical activity causes changes in your blood vessels, muscles, metabolism, and brain, all of which promote heart health.
If you go for a brisk walk, you will immediately notice changes in your body. Your heart beats a little faster, your breathing rate increases, and you can feel your leg muscles working. But you may need to be made aware of the various other physiological changes that occur in your body when you exercise, some of which offer benefits similar to those of common medications.
Together, exercise-induced changes can prevent or improve all significant risk factors contributing to heart disease, such as high blood pressure, diabetes, obesity, and high cholesterol. “Exercise can also improve mental health issues such as depression and stress, which are common but often overlooked factors in cardiovascular problems,” says Aaron Baggish, MD, a cardiologist, professor at the University of Lausanne in Switzerland, and founder of the Cardiovascular Performance Program at Harvard-affiliated Massachusetts General Hospital.
Being physically active also helps you live longer, especially since regular exercise helps prevent premature death from heart disease, as outlined in a paper published Sept. 13, 2022, in the Journal of the American College of Cardiology, which details the cardioprotective effects of exercise. Here’s how exercise affects the body and brain and how these adaptations protect your heart. See “Exercise Recommendations and Examples for aerobic and muscle-strengthening activities.”
A stronger heart
Over time, exercise increases the heart chambers’ size and conditions the heart. As a result, the heart relaxes more easily and pumps more efficiently, requiring less effort to send blood throughout the body.
Better blood vessels
High blood pressure is the result of stiff, inflexible arteries. Exercise increases the amount of blood circulating through the body by up to 25%, which over time, causes the blood vessels to dilate slightly and become more flexible. Exercise also stimulates the production of nitric oxide, a molecule that relaxes and widens blood vessels.
Aerobic and weight training exercises can slightly reduce blood pressure in people with normal blood pressure. If you have high blood pressure (defined as 130/80 mm Hg or higher), the average reductions are more significant: between 5 and 7 systolic pressure points (the first digit of the reading). “This reduction is similar to that achieved by taking blood pressure medication,” says Dr. Baggish.
Muscles: the weak point?
During a workout, muscles produce a protein called GLUT-4, which improves the body’s ability to convert glucose (sugar) into energy by making cells more sensitive to insulin. This hormone enables the cells to absorb glucose. That’s why exercise helps prevent and treat type 2 diabetes. “If everyone exercised enough, there would be almost no type 2 diabetes, largely due to the sedentary lifestyle typical of Western countries,” says Dr. Baggish. Type 2 diabetes-narrowly linked to excess weight-does not exist in primitive societies, where physical activity is part of the lifestyle, he adds.
Any of these exercises can reduce your HbA1c by 0.7 percentage points, a reduction similar to that achieved with some diabetes medications. (HbA1c is an average measurement of your blood sugar level over the past three months; an intermediate level is below 5.7%, and levels of 6.5% or higher indicate diabetes).
Metabolic transformation
Although exercise is reputed to help people burn calories and lose pounds, the weight loss resulting from the activity is usually only dramatic if regular exercise is combined with a healthy, balanced, low-calorie diet. However, exercise does help reduce visceral fat, which accumulates around the liver and other organs and is closely related to an increased risk of heart disease. Exercise has also been shown to modestly reduce triglycerides (the most common type of fat in the blood) and lousy LDL cholesterol.
Benefits for the brain
Regular exercise is believed to help reduce the body’s “fight or flight” response, which plays a role in chronic stress and anxiety. Exercise can also release natural chemicals similar to cannabis, increasing your sense of well-being. In addition, Dr. Baggish and colleagues have recently shown that a single 30-minute moderate exercise releases several proteins into the bloodstream, including brain-derived neurotrophic factor (BDNF). BDNF directly affects brain function, particularly mood and thinking ability. All these effects may explain why regular aerobic exercise is as effective as any antidepressant drug, he says.
And while the heart may reap most of the many benefits of exercise, it may be the effect on your brain that prompts you to start moving more. “You can’t feel your nitric oxide levels or your blood pressure go down. But the emotional benefits of exercise are immediately noticeable,” says Dr. Baggish.
