The main problem with this is how you conceptualize "hunter-gather" exercise. Hunter-gatherers comprise ancient societies spread across the planet in a huge range of ecosystems, from the Arctic shore to African deserts. Most of the remaining hunter-gatherers live in very marginal or sensitive environments that are difficult to sustainably convert to agriculture, like deserts or deep rainforest. As with most articles of this type, I fear that the authors are assuming an overgeneralized and not-very-empirically-grounded overview of "the" hunter-gatherer lifestyle and exercise regimen. Their sources to characterize hunter-gather lifestyle include things like The Paleolithic Prescription (and some paywalled journal articles).

There were hunter-gatherers where everyone walks thousands of miles over the course of the year, and hunter-gatherers where people stay near their villages, and hunter-gatherers where everyone travels great distances, and hunter-gatherers where the women stay at home, and societies where everybody stays at home and just pulls some fish or brazil nuts out of the river/forest when they're hungry, and hunter-gatherer societies so rich that they had hierarchical proto-states with leisured elites and slavery. And most hunter-gatherer societies disappeared so long ago that we simply have no real information about them, as far as questions like this go.

And frankly, looking at their Table 2, while it is true that the actual activities people may do on day-to-day basis may be different (carrying logs vs. carrying groceries) at the same level of activity, the premise that hunter-gatherers had very different exercise patterns may be exaggerated. Compare the discussion here: https://www.psychologytoday.com/blog/the-human-beast/200910/...

"Detailed research on two hunter-gatherer societies (or "foragers") allows us to calculate how active they are. These are the Ache of Paraguay and the !Kung of the Kalahari Desert in southern Africa. The !Kung are rather smaller (at about 100 lbs) and have comparatively low activity levels whereas the Ache are bigger (at about 130 lbs) and highly active thanks to their high birth rate.

A !Kung male uses about 2,200 (kilo)calories per day in total, almost exactly the same as a male office worker... Out of their respective total daily energy consumption, the !Kung use about 894 calories on physical activity (compared to 607 for office workers) whereas the Ache use a whopping 1772 calories this way.

Since the !Kung and Ache are so much lighter than Americans, it is important to take body weight into account. ...If Americans wanted to be as active as the !Kung, they would need to add the equivalent of 3.8 miles of walking to their daily activity. ...An hour-and-a-half of shopping with a cart uses about the same amount of energy as walking 5 miles."

Sure, the !Kung are exercising more, but only on the scale of say, walking/cycling instead of driving for short trips. Not on the scale of running daily marathons. It seems like an exaggeration to say: "Humans remain genetically adapted for a very physically active hunter-gatherer lifestyle. Many of the health problems endemic today result from lifestyle that is at odds with this evolutionary milieu."

Although to be fair they do insist that the difference does just imply a need for some more low- to moderate-intensity exercise.