We’ve all heard it before: regular exercise benefits the heart—increasing its strength and endurance, lowering the possibility of a heart attack. Scientists, doctors, and fitness gurus rarely all agree, but this fact is the exception. The cardiovascular benefits of working out is one of the most verified and consistent pieces of health truths that have ever been given to anyone.

But how exactly does it do that?

#1: By Increasing Your Blood Vessel Capacity

Your cardiovascular system is like any other system—the more you use it, the more it adapts to use by getting stronger. Any sort of physical activity that raises your heart rate forces your heart to pump more blood to your muscles, which need more oxygen. The higher blood volume will slowly push your blood vessel walls outward, forcing them to become more elastic and increase their capacity. This lowers your blood pressure and helps prevent the risks of blood clots.

There is some evidence to suggest that your cardiovascular system actually creates more capillaries and small blood vessels around your heart as a response to regular exercise. This allows blood to move more efficiently while giving the blood alternate travel routes if it encounters a blockage.

#2: By Making Your Heart Walls Stronger

Like all muscles, the heart becomes stronger the more it works. When you regularly exercise, the heart walls pump more deeply and effectively, pushing blood out of the heart more strongly. The most effective exercise for these benefits is interval training, where you increase and decrease your heart rate suddenly in intervals. This has a few different benefits for your body.

One, it reduces the chances of blood clots forming in your atrial chambers and allows all of your blood to leave your heart with every beat. Two, deeper pumps and stronger heart walls means you’ll be able to increase oxygen flow with less heartbeats. Less heartbeats reduces blood pressure, lessening the strain on your blood vessels.

#3: By Reducing Stress On Your Heart

Of course, regular exercise doesn’t just strengthen your heart. All of your muscles, from your calves to your back, become stronger and more efficient as you continue exercising. In fact, some research suggests that muscles can pull oxygen from the blood more effectively the more you work out. As your muscles become stronger, they require less and less blood in order to function at optimum levels.

This benefits your heart by requiring less heartbeats in order to power your movement, allowing your heart to relax. This is especially true for daily life, as the fitter you become, the lower your resting heart rate will be. By working less hard, you’ll reduce blood pressure (see the theme here?) and allow your heart to build strength through periodic exertion, not constant strain.

This article contains general information about medical conditions and treatment. This information is not to be treated as medical advice. Inquiries about your health should be consulted with a healthcare provider.