Humans were built for endurance, and new research has revealed that human hearts can physically change, allowing our bodies to have greater stamina. An article in Science Magazine, written by Eva Frederick, talks about how the hearts of runners and non-runners have clear differences. Researchers used ultrasounds to quantify the shape and size of adult male hearts. Those who exercise for long periods of time, such as endurance runners or farmers, were shown to have larger, elongated ventricles with thin walls. The ventricles are the portion of the heart that pump blood to the lungs or the rest of the body. In contrast, non-runners were shown to have much shorter, wider ventricles with thick walls. The longer ventricles allow endurance runners to hold a larger volume of blood for a longer period of time, which can help increase stamina during prolonged exercise. The longer ventricles that hold more blood will result in a more efficient heart, and lower a person’s heart rate. This can lower both bad cholesterol and blood pressure.

According to Eva Frederick, humans most likely evolved to have our hearts stretched by exercise in order to survive in humanity’s hunter-gatherer stage of civilization. One of the first eras of human survival involved hunting large prey by following them for miles on end. This need for extreme endurance is what likely forced human hearts to adapt to such a rigorous lifestyle. Ironically, according to research, the societal evolution of the hunter-gatherer lifestyle to the more technologically advanced civilization of today is why heart conditions are so common. Sedentary humans have no need to build endurance and change heart shape. When hearts are in a short and thick natural state they are more susceptible to heart disease.

According to Tracy Beth Høeg M.Dd, PhD, in “I Run Far” there have been two studies that show different benefits of running. The first study took about 15 years of comparing runners and non-runners. The runners had about a 30 to 45 percent lower risk of heart conditions and an overall mortality with about three year life expectancy benefit. Experiments have demonstrated that endurance exercise, such as running, can impact both the entire person and their heart.