Quirks & Quarks

Squat, don't sit: The way we are sedentary could make a big difference to our health

Scientists studied hunter-gatherers to measure the posture muscle activity to get a glimpse into our evolutionary past

Evidence from hunter-gatherers suggests couches and chairs made inactivity less healthy

Squatting activates more muscles than sitting, which is linked to the risk of cardiovascular and metabolic diseases. (Soe Than Win / AFP via Getty Images)
Listen7:39

If our ancestors were anything like hunter-gatherers from eastern Africa, what we do with our bodies when we're relaxing could be playing a significant part in chronic health issues today.

"Our bodies are likely adapted to much more consistent levels of muscle activity throughout the day," said David Raichlen in conversation with Quirks & Quarks' Bob McDonald. 

Raichlen, an associate professor of biological sciences at the University of Southern California, and his team have been studying the Hadza hunter-gatherers of Tanzania to better understand their lifestyle as a window into our evolutionary past.

The Hadza don't have chairs. They don't have couches. So when they're resting, they're using postures like squatting or kneeling or they're sitting on the ground.- David Raichlen, University of Southern California

In previous research he and his team found Hadza people had low levels of cardiovascular and metabolic disease. "They don't suffer from the kinds of chronic diseases that we see, or at least at the same levels that we see, in more industrialized societies like the U.S. and Canada."

In his new study published in the journal PNAS, he said and his team set out to study how much downtime hunter gatherer societies have. What they do when they relax, he said, could "perhaps help us understand why inactivity has negative health effects today."

Hunter gatherers are inactive for a 'surprising' amount of time 

Not surprisingly, the Hadza people who forage on foot and hunt with bows and arrows are much more active than we are. 

Raichlen measured their activity by taping an accelerometer, similar to a commercial device like a Ftbit, to their thighs and found they get more than three times the physical activity that is recommended in U.S. federal health guidelines. 

"We kind of assumed this hunting and gathering lifestyle probably just doesn't leave a lot of time for being sedentary, especially compared to our lifestyles here, but we were surprised," said Raichlen about his findings. 

"They are inactive or sedentary for about as long as we are, on average about 10 hours per day, which is pretty similar to what happens in industrialized societies."

The Hadza in Tanzania tend to squat or kneel when taking a break, which scientists believe may spare them from some risks for heart and metabolic diseases. (David Raichlen of USC / Brian Wood of UCLA)

Big difference in how we spend our downtime

Even though the Hadza people were just as sedentary as we in industrialized societies tend to be, they way they spent their downtime is much more active than simply sitting on a chair or putting their feet up to recline.

"The Hadza don't have chairs. They don't have couches. So when they're resting, they're using postures like squatting or kneeling or they're sitting on the ground," said Raichlen. 

They observed the types of postures the Hadza used when they were relaxing and measured their muscle activity. 

"These kind of squatting postures elicit higher levels of muscle activity than sitting in a chair." 

It's really these kinds of more modern inventions, like chairs and couches, that seems to be a mismatch with that [evolutionary] past.- David Raichlen, University of Southern California

Raichlen's team found squatting postures elicit 20 to 40 per cent of the muscle activity of walking. Sitting only uses about five per cent.

"When you squat, once you get into that posture, you are activating muscles to keep yourself balanced over your feet," said Raichlen about why squatting requires more muscle involvement than sitting passively.

Working more physical activity into our downtime

What does this suggest for those of us living a modern lifestyle? "Well burning your couch might not be a bad idea," Raichlen joked. It does probably suggest that our bodies are likely adapted to much more consistent levels of activity throughout the day.

The take home message, he said, is that we all should get up and move more. 

Scientists recommend getting up and taking short exercise breaks to break up long periods of sitting. (Jens Schlueter / Getty Images)

Getting our bodies used to squatting, even if it's something our ancestors did, is likely not necessary. 

"It's really these kinds of more modern inventions, like chairs and couches, that seems to be a mismatch with that past."

So instead of figuring out a way to squat more while you work, a nice stroll around the office would probably do the trick to get a bit more muscle activity into periods of inactivity.

Produced and written by Sonya Buyting

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