Human hearts have evolved for Endurance, and we need it to stay healthy, suggests a new study comparing the hearts of humans, chimpanzees and gorillas, which found that the human heart can change shape to reflect more of a chimpanzee like structure when people don’t do endurance exercise.

Endurance is that ability of an organism/humans to exert and remain active for a long period of time, as well as its ability to resist, withstand, recover from, and have immunity to trauma, wounds, or fatigue.

According to new study published this week in the journal PNAS, one of the world's most-cited and comprehensive multidisciplinary scientific journals, the human heart remodels throughout the lifetime in response to a person's activity.

Human heart can change shape to reflect more of a chimplike structure when people don't do endurance exercise, says the study by research led by Aaron Baggish, along with a team of co-authors that includes Daniel Lieberman, a human evolutionary biologist at Harvard, and Robert Shave, a cardiovascular physiologist at the University of British Columbia Okanagan.

Baggish and team compared the shape and activity of the hearts of chimpanzees, gorillas and and four groups of adult humans -- endurance athletes, football linemen, subsistence farmers and relatively inactive individuals.

The researchers found that the hearts of both the football linemen and sedentary individuals experienced remodeling that made their hearts less adapted to responding to endurance challenges and more adapted to responding to pressure. The walls became thicker, and the heart didn't twist as well.

The researchers also studied four groups of people with different exercise and activity patterns. One group was composed of 42 people from the Tarahumara, a group of indigenous people from Mexico who are known for their distance running events, although Shave said the vast majority of the time they are not doing high intensity exercise. The ventricles in their hearts did not have as large a volume as the researchers found in the 42 endurance athletes the group studied. The team also studied 40 people who played the position of lineman in American football, and a group of 42 relatively sedentary people.

[blockquote footer=""]There’s one additional significant difference between the hearts of humans and apes. When human hearts pump, they also rotate. This twist helps push more blood out each time it beats, and also draw more blood in for the next time it pumps.[/blockquote]

The study emphasizes the importance of regular exercise. A modern diet could complicate the picture, but regular walking could be sufficient -- previous research showed that hunter-gatherers in tropical areas tend to walk roughly 6-9 miles every day. A hunter-gatherer is a human living in a society in which most or all food is obtained by foraging (collecting wild plants and pursuing wild animals).

"Humans have evolved this extraordinary long lifespan in comparison to most other species," said Shave. "But to maintain a healthy blood pressure, we need to maintain that moderate intensity physical activity throughout our lives."

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