We’re told we need X or Y minutes of physical activity to “live healthy and at peace.” And let’s be honest, the tone is often moralizing. But before we start counting minutes, we need to know what we’re talking about. What is physical activity, exactly?
Definition (bioenergetics version)
Any muscular action that uses energy counts as physical activity. Yes, typing these lines counts. The intensity is low, sure, but it’s still activity. To avoid shortcuts, we break it down into three main compartments:
- Mandatory (obligatory) physical activity,
- Spontaneous (or involuntary) physical activity,
- Voluntary physical activity. We’ll come back to intensity, but let’s start by defining these three categories.
Mandatory physical activity
These are movements tied to survival and reproduction. Once upon a time, hunting, gathering, carrying, and building filled the day. Today, urbanization and mechanization have greatly reduced this energy expenditure: less elbow grease, more comfort… and fewer calories burned. Result: this compartment has shrunk, and the others haven’t necessarily made up for it.
Spontaneous (involuntary) physical activity “Fidgeting” or everyday movement
All the little gestures we make without thinking (getting up, moving around, gesturing, tidying up…). This compartment varies widely with age, environment, mood, sleep… and training. Key point: a hard workout can reduce fidgeting for the rest of the day due to energy compensation. A concrete example: you burn 300 kcal at the gym, then unconsciously slow down enough to “take back” those 300 kcal afterward. Add an aggressive energy deficit, and spontaneous movement drops further: the body protects its reserves.
Voluntary physical activity
This is exercise in the usual sense: training or playing sports for health or fitness. When people “decide to be more active,” this is almost always the compartment they increase. The catch: if more exercise comes with less fidgeting (or even fewer mandatory activities), the net gain in total energy expenditure can be… zero.
The uncomfortable question: how much should you move each day?
Guidelines (e.g., 30 minutes of moderate exercise) mostly target voluntary activity and largely ignore the other two compartments. They work for some, not for others. Why? Because it depends on your levels of mandatory and spontaneous activity, their intensity, and how they vary day to day. We measure them poorly, so we sideline them… but their contribution can be decisive.
What to remember
- What matters is total 24‑hour energy expenditure, not just the workout.
- Exercise is great for improving fitness, but it can trigger compensations that reduce spontaneous movement.
- A harsh calorie deficit lowers spontaneous activity: “eat less, move more” is trickier than it sounds.
So, how much physical activity? The most honest answer: probably more, more constant and with appropriate recovery.
- More mandatory activity, when feasible (walking for errands, carrying, DIY, gardening).
- More spontaneous activity (stand up often, walk while talking, take the stairs, multiply micro‑movements).
- More voluntary activity, tailored to your fitness and life (progressive intensity, sustainable volume).
And above all, better distributed: aim for an active day as a whole, not just a single “effort point.” Build a level of fitness that makes movement easy and frequent, then convert it into real‑world actions throughout the day. That’s where health improves—and where lasting results show up.