Exercised: The Science of Physical Activity, Rest and Health

Let’s begin our journey with a gentle realization: the world we inhabit today is vastly different from that of our ancestors, not just in its technology or comforts, but in how we think about movement itself. Did you know that the very idea of 'exercise'—as something we do for health or fitness—is a modern invention? For most of history, people moved because they had to. They walked miles to fetch water, hunted for food, built shelters, and cared for children. Movement was woven into the fabric of everyday life, not a separate activity to be scheduled or worried about.

Imagine a community in rural Africa, where women carry water on their heads for miles, or a child in the Andes who runs up steep hills as part of daily chores. These are not workouts—they are life itself. Our ancestors did not run for fun or walk for heart health. Instead, every step, every lift, every climb was purposeful. The treadmill, now a symbol of modern fitness, was once a grim tool of punishment in Victorian prisons, forcing inmates to trudge endlessly as a form of discipline. This paradox—of paying to sweat on machines that once symbolized suffering—captures our strange relationship with exercise today.

Words themselves reveal this shift. The term 'exercise' entered English in the Middle Ages, describing hard labor like plowing or training for war. Only in recent centuries did it come to mean planned, voluntary activity for health. Today, we see gyms on every corner, wearable devices tracking our every move, and a booming industry built on the idea that we must compensate for our sedentary lives by exercising. Yet, our bodies and instincts are shaped by a world where movement was not optional, but essential.

Why does this matter? Because it helps us understand why so many struggle with exercise, why guilt and confusion surround it, and why modern solutions often feel unnatural. We are not lazy; we are mismatched to our environment. Our ancestors did not need to 'find time' to move. Their survival depended on it. As we move forward, let’s carry this insight: our struggles with exercise are not failures of willpower, but echoes of our evolutionary past. Next, we’ll explore how inactivity—so often blamed and shamed—is actually a deeply rooted, adaptive part of being human.