Main content

How much exercise should you really be doing?

Is modern exercise a wellness cult? Or is it a vital cure for a world that's struggling with ill health and stuck on the sofa?

Most of us might like to get a bit fitter, but how easy is it to actually start exercising and give up sedentary habits?

In Exercise, the third series of A Thorough Examination, Drs Chris and Xand van Tulleken investigate the science of exercise and the dangers of inactivity.

Here, Xand explains how the podcast came about and what he (and, reluctantly, his brother Chris) learned…

Have you ever muttered to yourself, in fury and righteous indignation, “I’ll defy all their expectations of me”? Maybe you’ve fallen to your knees and, as rain poured dramatically around you and thunder and lightning rolled across the sky, screamed “I’ll show them ALL!” And no doubt you really meant it too, I know I did.

I had been nagged by my family for years to lose weight, to get my act together and to take care of myself. And guess what? I did. And not only that: the guy who had nagged me most of all – my own twin brother – well, he gained weight and became unfit and unhealthy. Divine justice of the sort rarely seen outside of musicals set in American high schools.

Photo by Jonathan Birch © ³ÉÈË¿ìÊÖ

A crisis of inactivity

This story of redemption was the subject of the first two series of A Thorough Examination. In Series 1, my identical twin brother Chris had a plan to force-feed me ultra-processed food while I talked to scientists about how unhealthy it was. A Clockwork Orange meets Alan Carr’s Easy Way to Stop Smoking.

Photo by Jonathan Birch © ³ÉÈË¿ìÊÖ
Why exercise is so good for us: it steals energy away from harmful processes in the body.

It worked. Two years later I was 30kg lighter, fit, healthy and feeling good. Chris, however, had been writing a book and had started to fall apart.

For this third series, I wanted to focus on exercise: it doesn’t get nearly the attention that diet, smoking or alcohol do, and yet we are facing a crisis of inactivity. It was also my chance, after all those years, to finally do some nagging of my own.

Stop nagging and let it go

Our kick-off meeting for the project began with a casual check-in. “So, Chris, how are you getting on with your health?” He instantly got as angry as I used to get at him.

What we had learned in Series 1 and 2 was that nagging family members doesn’t work. We almost killed each other, stopped only by a brilliant psychotherapist called Alasdair Cant. Alasdair told Chris to leave me alone. Everything got easier after that point.

Exercise is a hard sell to a sedentary middle-aged man like my brother. It’s painful, tiring, undignified and time consuming. Chris dug in. “Exercise is bad for you! You’ve joined a cult! You’re obsessed!” he’d protest.

So, over the past year, we’ve been speaking with world experts to try and resolve this argument…

Boost your immune system and reduce anxiety levels

Exercise is massively important. It will reduce or improve almost every kind of health problem, physical or mental. And you can get the benefit at any age pretty much instantly.

What should you do? And how much? Here’s the most helpful thing I learned, from psychology professor Ryan Mackay: set yourself an easy, achievable goal. We learn who we are by observing ourselves. If you try and fail to train for hours a day you learn you’re a failure. If you aim for one short walk every other day and succeed you learn you’re someone who can stick to a plan. And so you do more.

We also hear from Professor Herman Pontzer on his ground-breaking studies comparing the metabolism of very active hunter gatherers and very sedentary office workers. Unbelievably, they burn pretty much the same number of calories per day! His work explains why exercise is so good for us: it steals energy away from harmful processes in the body. If you exercise you don’t burn many more calories per day in total so you don’t lose much weight. But whenever I'm on my exercise bike now, instead of thinking about burning away fat, I imagine how the exercise is stealing calories away from processes like inflammation caused by my immune system. Exercise is relaxing because it seems to reduce the calories you have available for dangerous anxiety and stress. It is an extraordinary scientific breakthrough.

Who burns more calories – hunter-gatherers or office workers?

Incredibly, they both burn the same, explains evolutionary biologist Prof. Herman Pontzer

How did we get on?

Everyone told us: do something sustainable, enjoyable and joyful: dancing, gardening, walking. The more you can do the better. But you’re not to blame if you’re struggling: sedentary people are highly profitable. Broadcasters, social media companies, video games makers, car companies, food delivery apps, out of town supermarkets. They all profit from us sitting down: our world is no longer built to allow us or our kids to move easily.

I hope the series will inspire people to move themselves more: to realise, like Chris did, that I'm right about this. Exercise will make you happy and healthy. And I also hope it will make people notice how much of our freedom to move is being stolen from us all for profit and think about how to resist this.

Most importantly Chris finally uttered the magic words “you’re right” to me. Very satisfying.

Health matters on Radio 4