Does the prospect of enduring a second lockdown feel like deja vu all over again? And are you worried about its renewed effects on your body? I am. To cope with the monotony and strain of confinement, my family did a lot of stress-baking, but my biggest problem was being too sedentary. I tried to jog regularly, but my inability to go to work or other places curtailed my physical activity levels drastically. According to my iPhone, my average number of daily steps decreased by about half. Apparently, my experience was typical. Working from home and prohibitions on going out also kept people at their desks for nearly an extra hour a day, and surveys suggest that almost half of UK adults claimed to have put on weight during the lockdown.
How can we cope better with a second time round, especially in terms of exercise? Knowing the past helps us understand the present and plan for the future, and I study the evolution, biology and anthropology of human physical activity. In addition to doing experiments in my laboratory, I have travelled all over the world to observe the diverse ways that non-westernised, non-industrial people – that is most of humanity – use their bodies. My experiences and other research have helped me appreciate how recent decades have reduced and altered physical activity in places such as the UK and the US, lockdown or no. Fortunately, these perspectives also provide useful insights into how we can do better during the next lockdown and afterwards.
According to careful studies that have monitored hunter-gatherers in Tanzania and elsewhere, foragers typically engage in about two-and-a-quarter hours a day of moderate to vigorous physical activity. Every day, even in their 70s, hunter-gatherer women and men walk between five and nine miles, often carrying heavy loads, and they also spend hours doing other activities like digging. Farmers who don’t rely on tractors and other machines generally work even harder. Thanks to labour-saving inventions, billions of people never have to elevate their heart rate or break a sweat. Prior to the pandemic Britons averaged about half an hour a day of moderate to vigorous physical activity.
Does our newfound sedentism mean we have become lazier? Decidedly not. Avoiding physical activity that is neither necessary nor rewarding is a fundamental, universal instinct among adults. To be sure, in every culture children play, adults sometimes engage in sports, dance, or otherwise move for fun, but generally humans sit whenever possible. Even hunter-gatherers sit for almost 10 hours a day, the same as most westerners. From an evolutionary perspective, this inertia makes sense because in the past, when food was usually scarce, energy spent on discretionary activities, such as a five-mile jog, diverted precious calories from the only outcomes natural selection really cares about: taking care of the body’s needs and having as many babies as possible.
And therein lies a conundrum, because while it…