Taking evolution to heart
An international research group at UBC, Harvard University, and Cardiff Metropolitan University has discovered how the human heart has adapted to support endurance physical activities. The research examines how the human heart has evolved and how it adapts in response to different physical challenges, and will bring new ammunition to the international effort to reduce hypertensive heart disease.
The study analyzed 160 humans, 43 chimpanzees, and 5 gorillas to gain an understanding of how the heart responds to different types of physical activity. In collaboration with Harvard University’s Daniel Lieberman and Aaron Baggish, UBC professor Robert Shave and colleagues compared left ventricle structure and function in chimpanzees and a variety of people, including some who were sedentary but disease-free, highly active Native American subsistence farmers, resistance-trained football linemen, and endurance-trained long-distance runners.
The wide variety of participants were specifically recruited in order to examine cardiac function in an evolutionary context. From the athletic stadium to wildlife sanctuaries in Africa, the team measured a diverse array of cardiac characteristics and responses to determine how habitual physical activity patterns, or a lack of activity, influence cardiac structure and function. Guiding their inquiry is the well-known idea that the heart remodels itself in response to different physiological challenges.
Among humans, the research team showed there is a trade-off between these two types of adaptations. This trade-off means that people who have adapted to pressure cannot cope as well with volume and vice versa. Basically, the hearts of endurance runners aren’t great at dealing with a pressure challenge, and the weight lifter’s heart doesn’t respond well to increases in volume.
This new research provides evidence that the human heart evolved for the purpose of moderate-intensity endurance activities, but adapts to different physical (in)activity patterns. This research was published in the Proceedings of the National Academy of Sciences journal: https://www.pnas.org/content/116/40/19905.
