There's a common argument about human physical activity that usually splits into two distinct perspectives. One perspective suggests that athletic abilities are naturally ingrained in our DNA. While it's true that our genes do have some influence on our abilities in sports and exercise, no specific "athletic genes" have been identified by research. It's also worth noting that psychological elements, such as the ability to handle pain and self-belief, play a significant role in the making of champion athletes.

On the other hand, there's a perspective that emphasizes the impact of environment and culture on physical activity. This viewpoint is often associated with the "theory of the natural human", which suggests that people living in a more "natural state" are a true reflection of our inherent selves. This theory often romanticizes indigenous peoples like the Tarahumara as natural superathletes, untouched by modern laziness and decadence. However, the reality is that the Tarahumara lead a life of hard work as farmers and walkers, and only engage in long-distance running occasionally as a spiritual, competitive, and traditional activity.

In fact, the way humans engage in play and exercise is largely influenced by their culture. For instance, hunter-gatherers are active not because they are naturally athletic, but because their daily tasks require physical labor. Research on contemporary foraging tribes reveals that they only spend a few hours a day on moderate or vigorous activity, with the rest of their time spent on sitting and light work.

Over the past century, machines have significantly reduced the need for human physical labor, leading to a lack of exercise becoming a health concern. The concept of adults exercising purely for fitness is actually a recent development. While ancient philosophies did value the training of both mind and body, exercise was mostly a privilege of the elites until recently. The current emphasis on exercise for health only came about as physical labor became less common. Interestingly, even hunter-gatherers weren't particularly active compared to other mammals.

In conclusion, there's no such thing as a "normal" lifestyle or activity level for humans. Our physical exertion patterns are simply a reflection of our culture and environment. The recent rise in inactivity due to modern conveniences underscores the importance of choosing to exercise for health. However, the need for deliberate, planned fitness activity is a unique shift from our historical patterns.