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 43.

    Most all things are dependent upon your genes,including your tolerence to alcohol,cigarette smoking and certain foods but the pharmeceutical industry don't like the notion that there isn't really all that much you can do about your health.I would regard three minutes of intensive exercise as the waste of a chance for an extra ciggy myself.

  • rate this

    Comment number 42.

    Sounds like exercise for the lazy. I don't believe you can get a high level of fitness this way. Try doing a marathon with 3 minutes a week exercise. You'd collapse before you'd done 5 miles.
    That's not a very valid point - this article is referring to improving "fitness" not "stamina", which people often confuse but are not the same.

  • rate this

    Comment number 41.

    3 minutes, hmmm, still sounds like too much hard work.

    Is there any way I can get fit when I am sitting on the sofa watching TV which will allow me to eat my chips too?

    This is the 21st century, surely it's not beyond our scientists or marketing people?

  • rate this

    Comment number 40.

    If this improves the health of people who don't have the time or motivation to exercise, then I think it's fantastic. But I'd be surprised if it really makes you fit, strong, or helps your stamina. I do quite a lot of exercise (~12 hours a week, gym and running), and I've got to say that being very fit is the best feeling.

    I'll be sticking to my current routine, but good luck to those who try it!

  • rate this

    Comment number 39.

    Yes,right,OK doc. whens the book/dvd out? Lol.

  • rate this

    Comment number 38.

    HIT or interval training is method that is employee by many people.

    It is not a good idea for this methods to be touted as quick fix or miracle solution. That may benefit the audience viewing figures for the programme but will not help someone looking to improve their fitness or loose weight. A variety of exercises should be performed as different methods provide different benefits.

  • rate this

    Comment number 37.

    Interval training does work although for a beginner id say more like 20 minutes per day broken down at a low to moderate level otherwise your likely to pull a few muscles.Bear in mind this burns few calories and doesnt build stamina it merely stretches the envelope which your body can go to if pushed.Most forms of outdoor exercise are types of interval training anyway,cycling,running etc.

  • rate this

    Comment number 36.

    Oh if only this was true it would be a God send. 5 to 6 hours a week I spend killing myself in the gym when I could be spending a couple of minutes a week. If it sounds too good to be true, it usually is.

  • rate this

    Comment number 35.


    "Three minutes to long for me."

    I suggest you be done with it and pay someone to exercise for you. lol

    3 minute bursts of exersise sound a bad idea. The chances of injury without a proper warm-up would put me off.

    I have always assumed, based upon received wisdom, that you don't get a proper aerobic effect until you have exercised strenuously for at least 35 minutes.

  • rate this

    Comment number 34.

    There are several systems that work around the HIT principle like CrossFit, popular with the military. Most of the session don’t last long, goal is to complete the exercises in the shortest time possible. To reap the most benefits of course... you need to mix this with a proper diet, in many cases CrossFit is linked with what is called a Paleo diet with a basic goal of avoiding processed food.

  • rate this

    Comment number 33.

    I've been involved in getting and staying fit for well over 40 years, including intensive interval/anaerobic training.
    I'd advise caution with regard to anyone engaging in intensive exercise without having built up a foundation of basic fitness first.
    Otherwise,A and E departments are likely to have a spike in relation to cardiovascular-type incidents,I'd guess.

  • rate this

    Comment number 32.

    There's a difference between being healthily fit (i.e. able to do normal tasks and not being at high risk of strokes and heart attacks) and competetively fit (training and competing in physically demanding sports). This looks like the ideal solution for the former. And anyone who is actually lazy wouldn't even do this.

  • rate this

    Comment number 31.

    Many years ago, just for convenience, I had a routine that involved circuit exercises followed by a very short run that included a flat-out sprint up a steep hill. After I'd been doing this for a few months I was surprised to find myself carrying a very heavy hang-glider up a 2000 foot mountain without too much difficulty. The short intense burst did seem to work!

  • rate this

    Comment number 30.

    "Can three minutes of exercise a week help make you fit?"
    But this scientific research suggests that it can.

    Sometimes research can produce results that fly in the face of common sense - that's the part and parcel of our learning more about the world and ourselves...

  • rate this

    Comment number 29.

    12 Garthrod
    Are we the only ones who noticed that there was a 24% increase in insulin sensitivity ?, which is good if you have a family history of diabetes.
    I wonder how "fit" the decriers are?.
    It doesn't matter what you do people--just do something!

  • rate this

    Comment number 28.

    I did lean forward to type this in energetically for twenty seconds. Does that count?

  • rate this

    Comment number 27.

    Another definition of fit: "The ability of the heart to return back to restHR after elevated levels, be that through exercise, trauma or other factors."
    Measurement: a VO2 rating is one method of measurement. Harvard Step Test?
    You see, my definition is quite, quite different to your definition of "fit".

    Therein lies the problem: what are you hoping to measure & thus how to measure "fitness".

  • rate this

    Comment number 26.

    Come on, this is utter nonsense. Anything who regularly runs or keep fit will tell you that 3 minutes is barely enough time to get properly warmed up never mind give you a full work out. Realistically you need at least 20 minutes three times a week.

  • rate this

    Comment number 25.

    Three minutes to long for me.

  • rate this

    Comment number 24.

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



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