Katy Bowman, a biomechanist and author of Move Your DNA, points out that, "Perhaps in our quest to go intense for short periods of time for fitness, we've left untrained the ability to carry our bodyweight long distances at a moderate, easy pace."
Bowman points to a recent study that analyzed the physical activity patterns and cardiovascular health of a modern tribe of hunter/gatherers in Northern Tanzania. The study participants, ranging in age from young adults to those in their 70s, moved around at a moderate pace for at least two hours a day, doing things like walking, digging, foraging, and the like.
This basic physical activity was more than 14 times as much as Americans taking part in epidemiological studies, and participants showed no evidence of cardiovascular risk factors. Basically proving, once again, that moving a lot does wonders for overall health.