Human heart evolved for endurance

Adaptations in the heart's left ventricular structure and function likely helped preindustrial humans cope with the demands of endurance required for survival, a study finds. Great apes tend to engage in short, intense bouts of resistance physical activities, such as climbing and fighting, whereas preindustrial humans engaged to a greater extent in endurance physical activity, which was required initially for hunting and gathering and later for farming. Robert Shave, Daniel Lieberman, Aaron Baggish, and colleagues report that the human heart evolved to enable endurance physical activity in humans. The authors compared left ventricle structure and function in 43 chimpanzees, 40 sedentary disease-free humans, 42 subsistence farmers, 40 resistance-trained football linemen, and 42 endurance-trained runners. Whereas chimpanzees showed more resistance exercise-related adaptations such as spherical ventricles, humans showed more endurance exercise-related adaptations, including longer ventricles. Runners, and to a smaller extent, farmers showed more endurance exercise-related adaptations, such as large chamber size and stroke volume, compared with chimpanzees, physically inactive humans, and football linemen. The authors suggest the existence of a trade-off between these 2 types of adaptations among humans. Taken together, the findings highlight the plasticity of the human heart across lifestyles and over evolutionary timescales. According to the authors, the results also suggest that the human heart's evolved adaptations predispose people to hypertensive heart disease in the absence of endurance physical activity.

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Article #19-06902: "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart," by Robert Shave et al.

MEDIA CONTACTS: Rob Shave, University of British Columbia, Kelowna, CANADA; e-mail: rob.shave@ubc.ca; Daniel Lieberman, Harvard University, Cambridge, MA; e-mail: danlieb@fas.harvard.edu; Aaron Baggish, Harvard Medical School, Boston, MA; e-mail: abaggish@mgh.harvard.edu