Cardio and Heart

Cardiovascular exercise is the best way to improve your heart health. (Thus the term "cardio.")

Cardiovascular activity, at its most severe, can contribute to cardiac plaque, irregular heartbeats, and heart disease.

According to Dr. Dermot Phelan, director of the Cleveland Clinic's Sports Cardiology Center, steady-state cardiovascular exercise promotes heart health by increasing HDL (good) cholesterol, blood pressure, and triglyceride levels, as well as insulin sensitivity. Furthermore, it dilates the blood arteries and strengthens the heart muscle.

Experts believe it all comes down to oxidative stress. The physiological damage done to the body's cells during exercise is known as oxidative stress, and it is what causes the body to recover, become stronger, and become healthier over time. When stress levels reach dangerously high levels, the immune system is unable to keep up.

"It raises the question of overtraining," Phelan says, stressing that any type of exercise, when done excessively, may cause dangerous levels of inflammation in the body. Cardiovascular activity, on the other hand, has a better likelihood of being sustained for several hours at a time than higher-intensity activities such as strength training and sprinting. Consider this: every endurance activity, from triathlons to ultramarathons, is a cardiovascular exercise.