Harvard evolutionary biologist says humans evolved for sitting and walking, not endless gym sessions

A Harvard evolutionary biologist argues that human bodies are better adapted to sitting and walking than to relentless gym training and marathon running.

His position is not an excuse to remain on the sofa. Rather, it challenges the way modern culture has made strenuous exercise a marker of moral virtue, despite humans having evolved for a much less extreme level of activity.

The cult of sport under scrutiny

In recent decades, sport has evolved from a pastime into a form of social status. Gym subscriptions, smartwatches and fitness apps are often treated as signs of self-control and achievement. Across social media, toned physiques and training plans can resemble a form of personal marketing.

This culture may also deepen divisions. At one end are people recording every run, repetition and rise in heart rate. At the other are those left feeling ashamed, idle or unwelcome because they do not train intensely or regularly. Exercise then becomes an issue of identity rather than health.

When workouts become a test of moral worth, many people feel judged, while others quietly push their bodies past what they can safely handle.

Daniel E. Lieberman, Harvard professor of human evolutionary biology and author of Exercised, says this moralising pressure overlooks the way people really evolved. Although physical activity undoubtedly supports good health, organised “sport” as it is understood today was absent from most of human history.

People were certainly active, often extensively. However, movement had a practical role: obtaining food, collecting water, travelling and socialising. Most of that movement involved walking. Long sprints and repeated heavy lifting for appearance were uncommon. Exercising solely to improve fitness or looks is an extremely recent idea in evolutionary terms.

Humans evolved to sit – but not all day

Lieberman highlights an uncomfortable but straightforward fact: human ancestors spent plenty of time sitting and resting. Saving energy improved their prospects of survival when food supplies were limited and daily life was uncertain. When movement was needed, they generally used the most economical approach: walking rather than running, carrying things only when required and resting whenever possible.

This is not to say that people are “lazy by nature” in any moral sense. Instead, it reflects brains and bodies designed to conserve energy once essential needs have been covered. Gruelling training sessions for the purpose of a better selfie have no real counterpart in human evolution.

Being drawn to sit down after a long day is not a moral failure; it is a deeply wired response to conserve energy.

Lieberman’s interpretation of evolutionary history points in two directions. Humans are not designed to engage in intense sport continually. At the same time, they are not suited to the profound inactivity of modern office work, in which someone can remain at a desk for eight or ten hours with little more movement than a trip to the kettle.

Walk before you run

For Homo sapiens, walking was the usual means of getting around. Early humans travelled considerable distances while foraging or hunting, but generally did so at a manageable, consistent pace. Brief spells of running did occur, but they were not central to everyday existence.

That distinction matters when considering present-day exercise. A brisk walk undertaken every day is much more aligned with human biology than a rare, punishing attempt to “burn it all off” on a Sunday morning.

From an evolutionary angle, 7,000 steady steps each day fit us better than infrequent punishment sessions shared online.

Should we just sit down and stop exercising?

In short, no. Completely abandoning activity would harm health in ways that research has repeatedly demonstrated. Extended periods of sitting are associated with greater risks of heart disease, type 2 diabetes, certain cancers and premature death. The danger increases when people remain seated for hours at a time without interruption.

Lieberman instead advocates balance. He recommends keeping uninterrupted sitting periods to around 45 minutes. Afterwards, briefly standing up, stretching or walking a few steps can “reset” the body. Muscles begin contracting, circulation improves and metabolism is given a small lift.

He also maintains that the well-known 10,000-step daily goal is mostly arbitrary. For many people, health improvements appear to plateau sooner. Reaching approximately 7,000 steps a day seems sufficient to reduce the risk of early death for most adults, particularly alongside occasional periods of somewhat faster walking.

• Interrupt sitting every 45 minutes with a brief movement break
• Target around 7,000 daily steps instead of becoming fixated on 10,000
• Prioritise walking and gentle activity distributed across the day
• View demanding workouts as optional additions rather than everyday duties

For office staff, this could involve leaving the bus one stop sooner, taking the stairs or arranging short “movement breaks” between meetings. A gym membership and costly equipment are not necessary.

When sport helps – and when it starts to hurt

Even if modern sport is not “natural” in evolutionary terms, it can provide substantial benefits when approached sensibly. Health authorities identify several advantages of regular, moderate physical activity:

• Improved physical fitness, including a stronger heart and lungs
• Less stress and a reduced risk of depressive symptoms
• Support with weight management and tackling obesity
• A lower likelihood of chronic conditions, including diabetes and heart disease
• Lower risk of some cancers
• Better bone strength and joint function

These benefits seem greatest when activity is consistent and moderate, with sufficient rest included. Problems can emerge when exercise becomes excessive or compulsive. Some people train primarily for appearance, pursuing prominent muscles or dramatic weight loss to gain social approval. Others develop a cycle in which missing a workout causes anxiety, guilt or panic.

Too much training with too little rest can lead to injuries, hormonal problems, sleep issues and a strained relationship with food and body image.

The body requires recovery even at less intense levels of activity. Muscle development and numerous repair processes take place outside the gym rather than at the weights bench. Endurance athletes recognise that recovery days are as deliberate as training days. Rest is not laziness; it is part of the training load.

Sport, rest and the modern workday

For many adults, the key issue is not a choice between sport and sitting. It is coping with a lifestyle that imposes lengthy sedentary periods before requiring movement to be fitted around them. Commuting, desk-based employment and evening screen use can create hours of inactivity, including for people who run three times a week.

From Lieberman’s viewpoint, the answer is less about radically intense training and more about modest, ongoing changes. Walking meetings for quick discussions, standing during phone calls, short walks while considering a task and more purposeful household chores all contribute low-intensity movement.

A standard day might be arranged as follows:

Useful concepts behind the science

Two concepts help show why sitting and movement are both so important: energy balance and “non-exercise activity”. Energy balance describes the relationship between calories consumed in food and calories expended by the body. Sitting still burns far fewer calories than walking or physical work. Across many years, persistent sitting without dietary adjustment can raise that balance, contributing to fat gain and metabolic stress.

“Non-exercise activity” includes every type of movement outside formal sport, from walking to the shops and gardening to cleaning and pacing while on the phone. Studies associate greater amounts of this everyday activity with improved metabolic health, regardless of gym sessions. People who regularly move about, fidget and walk through the day generally do better than those who train hard for an hour before scarcely moving afterwards.

Light, frequent movement acts like low-dose medicine throughout the day, easing the pressure that long sitting puts on the body.

Practical combinations are most effective. Someone could complete two or three brief strength sessions each week to support muscles and bones, add daily walks for cardiovascular health and mood, and protect sleep and rest days for complete recovery. Sport may not be hard-wired into humans, but this balance of movement, sitting and rest suits both biology and everyday life.