Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart

Abstract

Chimpanzees and gorillas, when not inactive, engage primarily in short bursts of resistance physical activity (RPA), such as climbing and fighting, that creates pressure stress on the cardiovascular system. In contrast, to initially hunt and gather and later to farm, it is thought that preindustrial human survival was dependent on lifelong moderate-intensity endurance physical activity (EPA), which creates a cardiovascular volume stress. Although derived musculoskeletal and thermoregulatory adaptations for EPA in humans have been documented, it is unknown if selection acted similarly on the heart. To test this hypothesis, we compared left ventricular (LV) structure and function across semiwild sanctuary chimpanzees, gorillas, and a sample of humans exposed to markedly different physical activity patterns. We show the human LV possesses derived features that help augment cardiac output (CO) thereby enabling EPA. However, the human LV also demonstrates phenotypic plasticity and, hence, variability, across a wide range of habitual physical activity. We show that the human LV’s propensity to remodel differentially in response to chronic pressure or volume stimuli associated with intense RPA and EPA as well as physical inactivity represents an evolutionary trade-off with potential implications for contemporary cardiovascular health. Specifically, the human LV trades off pressure adaptations for volume capabilities and converges on a chimpanzee-like phenotype in response to physical inactivity or sustained pressure loading. Consequently, the derived LV and lifelong low blood pressure (BP) appear to be partly sustained by regular moderate-intensity EPA whose decline in postindustrial societies likely contributes to the modern epidemic of hypertensive heart disease.

Do vigorous-intensity and moderate-intensity physical activities reduce mortality to the same extent? A systematic review and meta-analysis

“…Interestingly, cardiological adaptations induced by strength and power exercise seem less cardioprotective (at least structurally) compared with programmes of moderateintensity physical activity. 35 Although our data indicates that both vigorousintensity and moderate-intensity physical activities in adulthood may reduce mortality to the same extent, this finding should not downplay the key role of physical activity to improve individual and population health. Some estimates suggest that, worldwide, physical inactivity causes 6% of coronary heart disease, 7% of type 2 diabetes, 10% of breast cancer and 10% of colon cancer.…”

The evolution of human endurance

“…A recent study indicates that the human heart has evolved to respond to training, being initially adapted at the same time for short bursts of intense activity or sustained endurance at lower rates of energy conversion [6]. A recent study indicates that the human heart has evolved to respond to training, being initially adapted at the same time for short bursts of intense activity or sustained endurance at lower rates of energy conversion [6].…”

“…Given that both heat dissipation and nutrient distribution require efficient blood circulation, it is not surprising that the cardiovascular systems, and especially the heart as the pump, have been implicated in selection for endurance. A recent study indicates that the human heart has evolved to respond to training, being initially adapted at the same time for short bursts of intense activity or sustained endurance at lower rates of energy conversion [6]. "We're actually saying that there is a specific cardiac adaptation to the type of training performed", commented Rob Shave, Director of the School of Health and Exercise Sciences at University of British Columbia in Canada and a co-author on the study.…”

Imaging Considerations for the Athletically Conditioned Heart: An Echocardiography-Focused Overview of the 2020 American Society of Echocardiography Recommendations on the Use of Multimodality Cardiovascular Imaging in Young Adult Competitive Athletes

“…As a species, humans are well-adapted for physical endurance and have developed a remarkable potential for sustained activity over thousands of years of evolutionary progression. 1 The majority of human history was preindustrial, during which moderate-intensity physical activity was likely necessary for survival. Thus, the capability to sustain longduration physical activity was honed over thousands of years of human development and the sedentary modern lifestyle is novel on an evolutionary scale.…”

“…Thus, the capability to sustain longduration physical activity was honed over thousands of years of human development and the sedentary modern lifestyle is novel on an evolutionary scale. 1 The pathologic stimulus of inactivity is likely responsible, at least in part, for the postindustrial increase in heart disease. During this era of relative physical inactivity, many of our technological advancements for assessing the heart have developed, including echocardiography.…”