It talks about a study that focused on comparing the hearts of chimps, gorillas, and humans (classed as one of the following: endurance athletes, football linemen, farmers, and inactive people). The researchers wanted to look further into human’s rather unique endurance ability – our ability to run/walk long distances.
For the gorillas and chimps, they spend a lot of time sleeping or just generally being inactive and have occasional quick bursts of energy and stress (such as quickly climbing trees or fighting). The researchers believed that these quick bursts caused spikes in blood pressure, but found that the shape of the gorilla and chimp hearts were suited well for these spikes. The hearts were round and had thick walls.
The human heart is different. It is larger than chimps’ hearts and less thick and also twists/rotates when it pumps blood (the gorilla and chimp hearts don’t). This allows for a more efficient blood delivery system and is ideal for endurance activities. The trade-off, though, is that the walls of the human heart aren’t as thick and thus are not as well-built for sudden blood pressure spikes.
Another interesting finding from the research is that if a person tends to live a sedentary life, their heart will “remodel” itself and become more like a chimp heart: less flexible with thicker walls. These hearts also appear to look like the hearts of people with chronic high blood pressure even before high blood pressure actually sets in.
They use this finding to emphasize the importance of regular exercise, noting that previous research showed that hunter-gatherers (in certain areas) tended to walk somewhere between six and nine miles a day. Physical activity, as we’ve all been told, is key to maintaining the flexibility and durability of the human heart.