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 223.

    Walking, that`s all anybody has to do to keep fit, just ordinary walking, anything else apart from swimming, forget it.

  • rate this

    Comment number 222.

    This is nothing new, HIIT training (the extra I is for interval) has been around for years. It is a very effective means of exercise. This 3 minute wonder is going to be of much use to anybody, but doing a full HIIT workout properly will no doubt improve fitness massively.

  • rate this

    Comment number 221.

    209 Some of us have no choice other than to look for a shortcut to keep what fitness we can - in my case swimming. Some of us are recovering from illness or coping with a disability - not all of us are blessed with 'perfect' health.

  • rate this

    Comment number 220.

    1 minute 3 times a week? Almost as good as sex!

  • rate this

    Comment number 219.

    Three minutes of intense activity a week sounds to me like a recipe for torn ligaments.

  • rate this

    Comment number 218.

    The results speak for themselves: For some people this WILL work.

    So what I really want to know now is this -
    How do folk get the blood test which will let them know whether this will benefit them personally or just waste their time?

    That's vital.

  • rate this

    Comment number 217.

    That's why a splinter can't go and do a marathon because they uses white muscle fibres while a marathoner won't splint since they have developed red muscle fibres. An ideal exercise should include weight lifting, short burst intensive cardiovascular workout followed by cooling off.

  • rate this

    Comment number 216.

    @177. 20 Cent
    If you exercise for an hour a day from th eage of 20 to 70 that is over two years of exercise. You need to live two years longer just to recoup the lost time. That extra life is in your 70s or 80s. I would rather have that time between 20 and 70.

    Brilliant - flawed, but brilliant :D
    Enjoy that exercise time, and be healthier and enjoy the extra (should you get it) in old age too!

  • rate this

    Comment number 215.

    So basically its an extremely short Spinner Bike routine, which is after all when done properly a half hour to an hour of HIT. Nothing new there then, although anything that gets people exercising is good as long as the Defibrillator is handy.

  • Comment number 214.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • rate this

    Comment number 213.

    I'm 59. About 18 months ago, paunchy and about a stone overweight, I started doing 5 mins exercise every other day - 50 leg raises (before I even get out of bed) followed by 15/20 push-ups. Paunch gone in 6 weeks, BMI down to 23 in 2 months, kept in shape ever since and feel great for it. I did stop eating bread too, but it's the exercise that makes all the difference.

  • rate this

    Comment number 212.

    Many people are reluctant to accept it. Why? The research was done by trained scientists/researchers. If it significantly reduces even just one health risk (say diabetes) it is a fantastic breakthrough; if it has wider benefits, even better. It needn't be in place of (e.g) cycling but maybe as a complement.

    I don't think it should be seen as just an alternative to other exercise but as a co

  • rate this

    Comment number 211.

    From what I recall of anatomy & physiology 20+ yrs ago we have different types of muscle fibres in the body - some are better for short duration, high impact use, others work for longer but generally at easier stuff. Exercising the short duration, high impact muscles in short bursts like this will also be good for the cardio-vascular system too. Good esp if you want max effect from least effort.

  • rate this

    Comment number 210.

    Where do they get 3 minutes from??
    2mins warmup + 20secs HIT then 2mins warmup + 20secs HIT then another 2mins warmup and 20secs HIT. This adds up to 7 minutes with 1 minute HIT.

  • rate this

    Comment number 209.

    With regular exercises, you get both achievement (physically & mentally) and self discipline. You will also look for the next goal.

    For those people looking for a shortcut instead of doing regular exercises, my advise is to take control of your diet which is more effective.

  • rate this

    Comment number 208.

    I manage an hour a day on the bike getting to and from work. A reasonable level of fitness can be achieved this way. So if you're within 10 miles of work get on your bikes!

  • rate this

    Comment number 207.

    The Canadian 5BX exercises used to work on a similar principle. I used them helpfully way back in the 80's.

  • rate this

    Comment number 206.

    This is dangerous nonsense. If an unfit person suddenly decides to exercise vigorously, it could kill them. Flat-out exercise has to be built up gradually and then maintained. Most experts recommend 20-30 minutes a time, 3 times a week. With aerobic exercise (e.g. running), you should monitor your heart rate as you go. There's plenty of well-established guidelines out there; read them!

  • rate this

    Comment number 205.

    Reply to the daver64 (193) The article makes no mention of "personal disposition" the physiological and metabolic changes that happen after a diet and exercise regime were observed in all individuals and all species studied. But you are correct in observing that the article confines itself to the treatment of obesity and does not explore its causes.

  • rate this

    Comment number 204.

    @179 Gordon Stokey
    "Also try 1.5k on an ergo in 6 mins" that is easy!
    I've only just started erging (as injuries prevent me doing things I prefer, like running)... and I'm already doing over 8k in half an hour and 15k in an hour :)
    I'm looking forward to getting home and having a bash at 174. rubmypineapple's workout, in line with this article :D
    I can see that being really tough!


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