Michael Mosley: “Three minutes of exercise a week will keep you fit”

The Horizon host tells Radio Times how our whole idea of exercise may be wrong

2012 and the new year trundles along. The resolutions that seemed so possible on New Year’s Eve are already beginning to pall.


Trips to the gym diminish – yet another waste of an annual subscription – and the carbohydrates on which you were so determined to turn your back are whispering “Eat me,” as the weather turns colder. 

Music to the ears of the overweight with an aversion to exercise is the news that Michael Mosley – he of engaging popular science series such as Inside the Human Body and The Brain: a Secret History – is about to give us Horizon: The Truth about Exercise. The buzz around the theory he’s to present is that it will blow the gym and jogging culture out of the water. He will, I’m told, prove that three minutes of vigorous exercise a week is enough to keep you healthy; and that, generally speaking, exercise contributes very little to weight loss.


Before our meeting I check on his background. If anyone in modern times deserves the title “Renaissance Man”, it’s Michael Mosley. That should be Dr Michael Mosley. The 54-year-old graduated in Philosophy, Politics and Economics from Oxford University and spent a couple of years in banking, following, one assumes, in the footsteps of his banker father. He, though, changed direction. He studied medicine in London, completed his training, became disillusioned with his chosen speciality of psychiatry and applied to be a trainee producer at the BBC. There he found his métier and has become the corporation’s most-valued communicator of complex scientific ideas.

I can’t resist the urge to arrange our meeting at a place where temptation to eat entirely the wrong kind of food is unavoidable. I want, literally, to get the measure of the man. Is he someone with no real understanding of the misery of a sweet tooth and the agony of trying to carry out the accepted, time-consuming exercise regime – 120 minutes’ moderate or 75 minutes’ vigorous activity, several times a week? Does he have a personal interest in the truth about diet and exercise or is he just looking to hit the headlines?


I am comfortably ensconced by the fire in the tearoom of Brown’s Hotel in London when a bundle of coiled energy skids to a halt at my side. He isn’t fat and couldn’t be described as sluggish. He sits opposite me, hugging the edge of his chair – ready, I feel, to blind me with science.

I get the ordering done first. What kind of tea would he prefer?

“Nothing to eat, thank you. Just a cup of tea will suffice.”

The waiter appears horrified that anyone should turn up his nose at cucumber sandwiches, scones and cream, tiny tarts and fancies of every hue. Nevertheless, I order food for one and begin my questioning.

Has he ever been overweight? The “No!” comes sharp and fast. Has he ever been a member of a gym? Another dismissive “No!” I understand he subjected himself to rigorous testing at Nottingham University to try out the theory, so what then is his interest in the topic?

He begins to relax, slyly taking a sandwich from the huge pile of food that’s arrived.

“I’ve never had a real weight problem, but like everyone I’ve occasionally been tempted by the gym. I’ve taken up the occasional offer of a trial membership and when I’ve stayed in a hotel I’ve used the facilities. Mostly to try to help me sleep. I’m a chronic insomniac and I suppose I’ve thought if I could get a sweat up, it would help me sleep. It doesn’t.” 


So what prompted a personal interest in exercise and health? “I’m at an age now when you begin to worry about these things. I discovered I have visceral fat when I made a programme about dieting. I had a scan that showed I’m sort of thin on the outside, but fat on the inside – the most dangerous way to be. It wraps around organs like the liver and kidneys and causes metabolic syndrome, low bone density and type 2 diabetes, and it’s most common in men.

“If you can’t afford a scan and you’re male, the best way to judge the problem is waist size. It should be less than half your height around the umbilicus. Most men underestimate it by two to four inches. My father had type 2 diabetes and there is a genetic element to it. So I knew that I needed to do something about it.” 

As we talk, items disappear from our tea. A few sandwiches, a couple of scones, a tart, a chocolate fancy. I ask, unsurprisingly, about changing one’s diet as a way of improving matters. 

He laughs at his inability to resist and launches into an explanation of why diets generally fail. “It’s not that people are weak-willed. It’s pretty easy to lose weight quickly on a strict diet, but then the body conspires against you. Fear of starvation, hunger, is a primal instinct. As you lose weight your metabolic rate slows. Your body encourages you to conserve calories by moving less. Fat is active and throws out hormones affecting appetite. The brain tells the nerve cells in your intestine that you’re hungry. Thus, 95 per cent of diets fail. And there’s a genetic element to this. Research shows that genes switched on in the foetus affect weight. There are studies of twins separated at birth who end up at the same weight, regardless of how they were raised.”


So, what about exercise? Surely, regular visits to a gym – 20 minutes on the bike or running machine, two or three times a week – will do the trick?

“Not so. We grossly underestimate the amount of time you need to burn calories. If you cycle steadily for an hour you’ll burn 500 calories. That’s a muffin. You’d have to cycle from Nottingham to Leeds – 78 miles – to burn a pound of fat, and one experiment in the US showed that even thinking about exercise triggers the hormonal response that makes you want to eat.

“That’s the problem with gyms. You get in the car. You park. You walk briskly on the treadmill for 30 minutes (200 calories). You shower and have a congratulatory muffin. It’s taken two hours. You’ve burnt 200 calories and consumed 500. It doesn’t compute.”

So putting weight loss aside, can just three minutes of exercise a week really be as useful as three hours on the treadmill? The answer lies, it seems, in the not-so-catchy acronym HIT. It stands for High-Intensity Interval Training, and research suggests that this short-burst approach is highly effective. “What they’re looking at in Nottingham is what’s required for good health: they’re measuring aerobic fitness and glucose sensitivity. And it’s inactivity that causes the problems of visceral fat and the metabolic problems that lead to diabetes.

“The average person sits for 12 to 14 hours a day. But if we move around, we activate the protein lipase. It sucks fat out of the bloodstream and transfers it to the muscles, where it can be burned.”

I’m still unconvinced that a mere three minutes’ vigorous exercise a week and the occasional stroll can control our glucose tolerance and aerobic fitness, predict our future health and possibly save the NHS millions by preventing common diseases, but Mosley has no doubts.

“What Nottingham and other studies are showing is that keeping active, getting off your butt, is the answer,” he says. The HIT approach, combined with gentler exercise such as walking and even fidgeting (yes, there’s an acronym for it and it’s NEAT – Non Exercise Activity Thermogenesis), will do the trick.

As teatime ends, Mosley explains he achieves his NEAT motion by getting up and having a walk around every hour when he’s working at his desk. He cycles a mile and a half to the station every day, building his HIT minute into his trip, and takes the stairs instead of the lift. He isn’t at all worried about the damaging impact on the gym and dieting industries this research could have. He heads off to the station at a smart pace.

I pay the bill and catch a cab. Must do better!

Horizon: The Truth about Exercise is on Tuesday at 9pm, BBC2 (11:20pm in Wales, Thursday 11:20pm in N Ireland)

Find out why three minutes is enough – and see Horizon’s three-minute exercise plan.


This is an edited version of an article in the issue of Radio Times magazine published 21 February 2012.