Can three minutes of exercise a week help make you fit?

Michael Mosley on exercise bike

A few relatively short bursts of intense exercise, amounting to only a few minutes a week, can deliver many of the health and fitness benefits of hours of conventional exercise, according to new research, says Dr Michael Mosley. But how much benefit you get from either may well depend on your genes.

When I first read studies which suggested that I could make significant and measurable changes to my fitness by doing just three minutes of exercise a week, I was incredulous.

But this apparently outrageous claim is supported by many years of research done in a number of different countries including the UK, so I decided to give it a go.

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Aerobic fitness is a measure of how good your heart and lungs are at getting oxygen into your body and is an excellent predictor of future health”

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My guide into the world of High Intensity Training (HIT), was Jamie Timmons, professor of ageing biology at Birmingham University.

Jamie assured me that by doing just three minutes of HIT a week for four weeks, I could expect to see significant changes in a number of important health indices.

The first, and the one I was most interested in, is insulin sensitivity. Insulin removes sugar from the blood, it controls fat and when it becomes ineffective you become diabetic.

My father was a diabetic and died from complications of that disease. Jamie assured me that research from a number of centres has shown that three minutes of HIT a week improves insulin sensitivity by an average of 24%.

The second improvement I was likely to see would be in my aerobic fitness. Aerobic fitness is a measure of how good your heart and lungs are at getting oxygen into your body and is an excellent predictor of future health. I asked Jamie why.

"The simple answer is we don't know," he replied. "What we do know is that it is a very, very powerful predictor of future health."

Genetic test

So if I could improve my insulin sensitivity and my aerobic fitness then that should improve my general health. But Jamie said there was a potential sting in the tail. There was a possibility that I wouldn't improve. Not because HIT doesn't work but because I've inherited the wrong genes.


Michael Mosley
  • Michael Mosley presents Horizon: The Truth About Exercise on BBC Two at 21:00 GMT on Tuesday 28 February 2012 or watch online via iplayer (UK only) afterwards at the above link

The fact is that people respond to exercise in very different ways. In one international study 1,000 people were asked to exercise four hours a week for 20 weeks. Their aerobic fitness was measured before and after starting this regime and the results were striking.

Although 15% of people made huge strides (so-called "super-responders"), 20% showed no real improvement at all ("non-responders").

There is no suggestion that the non-responders weren't exercising properly, it was simply that the exercise they were doing was not making them any aerobically fitter.

Jamie and his collaborators investigated the reasons for these variations and discovered that much of the difference could be traced to a small number of genes.

On the basis of this finding they have developed a genetic test to predict who is likely to be a responder, and who is not. Jamie offered me that test. But I would not be told the results until I had completed my HIT regime.

I agreed, had blood taken and went through some baseline tests to assess my starting point, fitness-wise. Then I began to do HIT.

Full throttle

It's actually very simple. You get on an exercise bike, warm up by doing gentle cycling for a couple of minutes, then go flat out for 20 seconds.

A couple of minutes to catch your breath, then another 20 seconds at full throttle. Another couple of minutes gentle cycling, then a final 20 seconds going hell for leather. And that's it.

Michael Mosley tries high intensity training

So how does it work? According to Jamie, and other researchers I spoke to, part of the explanation is (probably) that HIT uses far more of our muscle tissue than classic aerobic exercise.

When you do HIT, you are using not just the leg muscles, but also the upper body including arms and shoulders, so that 80% of the body's muscle cells are activated, compared to 20-40% for walking or moderate intensity jogging or cycling.

Active exercise also seems to be needed to break down the body's stores of glucose, deposited in your muscles as a substance called glycogen. Smash up these glycogen stores and you create room for more glucose to be sucked out of the blood and stored.

Somewhat sceptical I went off and dutifully did my four weeks of HIT, making a grand total of 12 minutes of intense exercise and 36 minutes of gentle pedalling. I then went back to the lab to be retested.


The results were mixed. My insulin sensitivity had improved by a remarkable 24%, which was extremely satisfying, but my aerobic fitness had not improved at all.

I was crestfallen, but Jamie was not surprised. It turns out that the genetic test they had done on me had suggested I was a non-responder and however much exercise I had done, and of whatever form, my aerobic fitness would not have improved. My dreams of winning Olympic gold ended there and then.

I will continue doing HIT because I can see the benefits. It won't suit everyone, because although it is short, it is extremely intense. Like any new exercise regime if you have a pre-existing medical condition you should consult your doctor before trying it.

Michael Mosley presents Horizon: The Truth About Exercise is on BBC Two at 21:00 GMT on Tuesday 28 February 2012 or watch online afterwards at the above link.


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  • rate this

    Comment number 203.

    I did martial arts training for years and got very fit: great stamina, flexibility, etc. It had proper warm-ups, then stretching. My particular style did include bursts of maximum intensity, which of course you can only keep up for four minutes, then back to moderate exercise. As a side-effect, I felt much more relaxed all the time and slept better.

  • rate this

    Comment number 202.

    168 #Have you an idea what I costs to heat & sterilise a full size swimming pool?Often... there's more life guards than swimmers. Even at £4.50 a ticket the pool will be losing money#

    Gosh what pool do you go to?My local pool's always busy & extremely well used.I'm as environmentally conscious as I can be eg I don't drive but swimming's one of the best forms of exercise going/ accessible to all.

  • rate this

    Comment number 201.

    I can see light now, it's as if a pair of blinkers have been lifted from my eyes ... All those months of hard training, pounding the streets for hours on end for that marathon I did were all for nothing! I should have kicked back, put my feet up for six months and simply stretched the legs for 3 minutes a week. If only I'd known. I could run it in sub four hours!

  • rate this

    Comment number 200.

    I feel the article should highlight the fact that 3 mins of HIT should not be a substitute for 30-60min of daily exercise, but in fact should be used as part of a daily routine.
    we need to be promoting lifestyle changes as we all know there is no quick method to losing weight, getting fit or getting money etc and we need to be installing hard work for prolonged time instead.

  • rate this

    Comment number 199.

    Too many times people have laughed when inquiring as to whether I've been at the gym whereas in fact I've mainly been doing menial things around the house - mowing the lawn, rearranging furniture, etc. Finally I feel as though I'm being vindicated through this research that small bits of activity like this can have very real effects on health/body. Maybe now they'll believe me?

  • rate this

    Comment number 198.

    Reply to Peter Sym (#184 ) - The laws of physics are intact. The paper describes how the body responds to diet and exercise by metabolising food more efficiently so you put on weight more easily than you did before. That's why nearly everyone not only puts the weight back on – they actually put more weight on then they had before.

  • rate this

    Comment number 197.

    Peter_Sym (195)

    "To run with no joint damage requires correct technique & correct footwear."
    "5 miles run on roads in step in 1 hour. Its crippling."

    That sounds like two problems in combination: if you're forced to run at someone else's pace, it's tiring AND more difficult to use proper technique. Then when you're tired, it's even more dificult. That's when the damage is likely to happen.

  • rate this

    Comment number 196.

    facebook shows me old school friends banging away in gym chasing an ideal body / ideal weight / faster time / longer distance who are never satisfied, calling others lazy just because they are not next to them on a machine. At least this is giving inspiration for those who don't want to rub shoulders with these soul-less robots

  • rate this

    Comment number 195.

    #194: thats the point I'm making (and which some seem to be misunderstand). To run with no joint damage requires correct technique & correct footwear. If you just pull on an old pair of trainers & start pounding the pavement you may hurt yourself.

    My knee damage came from the old 'Combat Fitness Assessment': boots, rifle, full webbing. 5 miles run on roads in step in 1 hour. Its crippling.

  • rate this

    Comment number 194.

    Peter_Sym (132) "Running on concrete in army boots has knackered my left knee"

    A PE instructor once told me "first put your foot down THEN put your weight down" - vastly reduces shocks to joints, and you run silently as a side effect. It means your weight is shifted MARGINALLY backwards as your feet come down. Leaning forward and stamping your feet (which some people seem to do) wrecks joints.

  • rate this

    Comment number 193.

    178.Chazz Trinder I actualy read that article, seems to me he's saying its very hard to keep the weight down when you have lost it because of personal disposition. At no point does he really refute that eating too much or excercising too little causes weight gain, rather he seems to be saying you need iron will power to stick to that which few people seem to manage.

  • rate this

    Comment number 192.

    Articles like this annoy me. There are so many levels of "fit", and it has different meanings to different people.

    Interval training is a tool that can be really benefitial. But it is important to remember that it is one of many tools. Just like all the available tools, a fat couch potato isn't going to become Olympic Champion just by using one. Any exercise is good, a mixture is better.

  • rate this

    Comment number 191.

    plenty of morbidly obese people in this country who could have done with an exercise regime about twenty years ago!

  • rate this

    Comment number 190.

    As a sports science student I am very much looking forward to this programme, for too long people have thought that the 'long and slow' method of training for aerobic fitness is the most effective and it is consistently being shown in the literature that this is not the case. And for those who think it is a shortcut, you're not doing it right!! the clue is in the name HIGH INTENSITY is vital!

  • rate this

    Comment number 189.

    This sounds useful as a cardiovascular exercise - ie to exercise the heart & lungs and get blood circulating. But I suspect there is simply not enough exercise in this regime to seriously burn fat and help loose weight.
    I think the danger is that some may latch on to this as a quick fix that doesn't really deal with all the issues.

  • rate this

    Comment number 188.

    177. 20 Cent - not really thinking are you? You imply exercise is boring but I enjoy cycling in the countryside - up to 15 hours a week in the summer. Just do what you enjoy, many enjoy working out in a gym of course. If you don't exercise you may find your life ends earlier than you expect - or when 50 you might be as healthy as I might be at 70! Looking forward to being bed ridden?

  • rate this

    Comment number 187.

    I definitely have this gene. Late 50s & doing lots of crazy stuff. I never do running or exercise machines. I do sets of intensive floor exercises that I have learned over the years but not very often. I never use the car locally but cycle instead. A week of full routine each night can take me from weak & stumbling to good military fitness. Sometimes can't believe it myself.

  • rate this

    Comment number 186.

    Longer periods of exercise if weight bearing increase bone density. Protect against some cancer including bowel. Have physiological benefits both from endorphins and getting outside. Give an opportunity for social interaction with other people. Reduce muscle wastage in older people. Lower bad cholesterol and increase good. Come on you have measured just two indicators interesting but not useful.

  • rate this

    Comment number 185.

    182 Desi Jatt

    365 x 500 kcal deficit = 182500 kcal deficit over a year.

    It takes 7700 kcal deficit to burn a kg of fat which means that 182500 kcal is equivalent to 23.7kg (3.75 stones). So your exercise regime didn't really effect your weight loss it was just because of your calorie deficit.

  • rate this

    Comment number 184.

    #178 That paper you link to says nothing of the sort: it says to lose weight requires SERIOUS effort and cutting hundreds of calories a day from the diet permanently. Your claim that diet and exercise has no impact on weight loss would violate the basic laws of physics. You cannot eat 2000 calories, burn 3000 yet not lose weight. I've taken 3" off my waist in 18 months with diet and exercise.


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