Public Release: 28-Nov-2016
Modern hunter-gatherers show value of exercise
University of Arizona
In a remote area of north-central Tanzania, men leave their huts on foot, armed with bows and poison-tipped arrows, to hunt for their next meal. Dinner could come in the form of a small bird, a towering giraffe or something in between. Meanwhile, women gather tubers, berries and other fruits.
This is everyday life for the Hadza, an indigenous ethnic group living around Lake Eyasi in East Africa and one of the last hunter-gatherer populations on Earth.
The Hadza live a very different kind of lifestyle -- and a very active one, engaging in significantly more physical activity than what is recommended by U.S. government standards. They also have extremely low risk of cardiovascular disease.
University of Arizona anthropologist David Raichlen and his collaborators, Brian Wood of Yale University and Herman Pontzer of Hunter College, have spent several years studying the lifestyle of the Hadza, which they say provides a glimpse into how our ancestors lived tens of thousands of years ago, and how that way of life may have impacted human evolution, especially with regard to exercise and health.
The U.S. Department of Health and Human Services recommends that people engage in 150 minutes per week of moderate intensity activity -- about 30 minutes a day, five times a week -- or about 75 minutes per week of vigorous intensity activity, or an equivalent combination of the two. However, few Americans achieve those levels.
The Hadza, on the other hand, meet those weekly recommendations in a mere two days, engaging in about 75 minutes per day of MVPA, researchers found.
Furthermore, and consistent with the literature identifying aerobic activity as a key element necessary to a healthy lifestyle, researchers' health screenings of Hadza people have shown that the population has extremely low risk for heart disease.
"They have very low levels of hypertension," Raichlen said. "In the U.S., the majority of our population over the age of 60 has hypertension. In the Hadza, it's 20 to 25 percent, and in terms of blood lipid levels, there's virtually no evidence that the Hadza people have any kind of blood lipid levels that would put them at risk for cardiovascular disease."
While physical activity may not be entirely responsible for the low risk levels -- diet and other factors may also play a role -- exercise does seem to be important, Raichlen said, which is significant because humans' physical activity levels have drastically declined as we have transitioned from hunting and gathering to farming to the Industrial Revolution to where we are today.
"Over the last couple of centuries, we've become more and more sedentary, and the big shift seems to have occurred in the middle of the last century, when people's work lives became more sedentary," Raichlen said.