Are all resting positions the same? An article published last March from Kent State University explores how the human body rests, and how our evolution from hunter-gatherers to modern office workers explains the mechanics behind why sitting in chairs can be detrimental to health and metabolism.
The researchers observed the human body during states of inactivity in a modern hunter-gatherer population of Tanzania, the Hazda. Much to our surprise, the Hazda tribe spends time in a nonambulatory position equal to the time industrial populations spend sitting.
Nonambulatory time means time not actively moving their bodies during walking or other forms of activity. In the case of the Hazda, the time they spend not walking doesn’t necessarily mean they are sitting. Even though the time spent resting was found to be equal, they seem to have escaped the metabolic consequences associated with sedentary lifestyles which populations of the industrialized world face.
What’s different about the way they spend their nonambulatory time?
In this study, the researchers used accelerometers worn on the Hazda’s thighs to measure their inactivity levels. The team also used electromygraphic data and observational data to reach their results: the Hazda spend 7.54–9.9 hours in a state of inactivity each day.
If this figure seems a little high to you, it’s because the common perception is that hunter-gatherers and other indigenous populations of the world are busy all the time, just making their ends meet to survive. With the Hazda, it’s how they spend the nonambulatory time that makes a difference to their health.
Unlike the modern office worker/tv watcher, the Hazda spend their inactive time mostly in squatting positions rather than sitting in chairs. When squatting, the muscles in the lower limbs are more activated than when sitting in a chair. Sitting in a chair is associated with lower levels of muscle activity and muscle contractions, resulting in lower muscle metabolism (which, you guessed it, means lowered metabolic function and increased risk of disease).
The authors of the study believe that the health of the human body is optimized when the body is not completely resting, even during periods of inactivity. Their results suggest our bodies were adapted to practice more consistent muscle engagement in our evolution, and it’s the lack of consistentmuscle engagement when resting that detracts from the health of our modern muscles.
How We Can Improve
We can get the benefits of active rest positions by squatting instead of sitting and choosing to sit less. In our modern world, sitting on a medicine or yoga ball or choosing a standing desk can provide the extra muscle activity we need to be healthy.
The human body wasn’t designed to sit in a sedentary position for extended periods of time. However, based on the amount of time that the Hazda spend not walking, it isn’t that resting itself is fundamentally bad. Our human bodies, minds, and spirits have to have periods of rest in order to function.
Rather, it’s about how we choose to position ourselves during these resting periods. Hopefully, this can relieve some of the guilt that the modern world experiences over not feeling productive or busy all the time — and can remind us that resting is an important part of being human. We just have to be mindful of how we do it.
Raichlen, David A., et al. “Sitting, Squatting, and the Evolutionary Biology of Human Inactivity.” Proceedings of the National Academy of Sciences of the United States of America, https://doi.org/10.1073/pnas.1911868117.