tired woman runner taking a rest after running hard on city road

    Just one minute of intense exercise is enough to improve your health

    30 March 2017

    An exercise regime known as the ‘one-minute workout’ has recently caught the attention of the media. The claim, which sounds a little unbelievable, is this: ‘One minute of intense exercise can be just as beneficial for our health as 30 to 60 minutes of steady moderate-intensity exercise.’

    You’ve all heard the cliché: if it sounds too good to be true, then it probably is. But is this the case with the one-minute workout? Is this just another one of those fleeting health fads, or is there some serious scientific evidence to support it? And, perhaps more importantly, should we all be doing it?

    We should all be exercising regularly, there’s no doubt about that. But exercise is a very complicated behaviour and working out the ‘best’ exercise for improving health is challenging. It depends on what you are trying to achieve. For example, the optimal exercise programme to reduce blood pressure may be very different from the optimal exercise programme to increase overall cardiovascular fitness or to promote weight loss.

    Public health guidelines for exercise understandably rely on a ‘one-size-fits-all’ approach. It is recommended that we all do a minimum of 30-minutes of steady moderate-intensity exercise on most days of the week. It’s a simple message and it’s based on good scientific evidence.

    The problem is that not enough people achieve this on a regular basis. About two thirds of us, in fact. And although many different things can get in the way of exercise, one factor common to many people is a lack of time.

    The one-minute workout
    High-intensity interval training (HIT for short) is proposed as a potential solution. By increasing the intensity of exercise and performing it in short intervals with periods of resting recovery, HIT may reduce the amount of time you need to spend exercising.

    The one-minute workout is based on a specific type of HIT, where the short intense efforts are performed at a maximal or ‘all-out’ effort; in other words, as hard as you can go. This approach, sometimes called sprint interval training (SIT), has been studied by exercise scientists for a while now. The classic SIT protocol involves six 30-second ‘all-out’ cycling sprints with four minutes of rest in between each one.

    And it works. It definitely works. One study reported that after just six sessions of SIT over two weeks participants doubled (yes, doubled) their time to exhaustion during an exercise endurance task (from 25 to 50 minutes). That’s a massive improvement. It’s even more remarkable when you remember the participants in these studies were performing just three minutes of actual exercise in each training session.

    More recent studies show that SIT can also lower blood pressure, reduce blood sugar levels, and improve the function of the heart and blood vessels. All of these are important for reducing our risk of disease.

    The problem is this protocol is extremely intense and probably isn’t a feasible exercise option for most people. It’s also not very time-efficient; because of the rest periods, the total time commitment is about 30 minutes a session, which is no different from guidelines for moderate exercise.

    But here’s the thing. There’s no reason to believe that SIT needs to be this long or this strenuous. Do we really need six sprints or can lower numbers be just as effective? Do the sprints need to be 30-seconds or can they be shorter? How low can you go and still get the desired health benefits?

    The answer appears to be very low indeed. Perhaps the strongest evidence for this comes from a recent meta-analysis. This analysis combined the data from 34 studies (including 418 participants in total) that had looked at the effects of SIT (with varying numbers of sprints) on changes in aerobic fitness (also known as ‘VO₂max’). VO₂max is the body’s maximal capability to take up and use oxygen during exercise, and improving it is probably the most important thing you can do for your health.

    The findings showed that performing just two ‘all-out’ 20-second sprints was very effective in improving VO₂max (about a 10 per cent improvement when three sessions of SIT a week were performed over six weeks). Adding extra sprints or longer sprints to the training session did not result in greater improvement.

    Another study (the one that’s generated all the hype) from researchers at McMaster University in Canada showed that a similar protocol (with three 20-second sprints) also lowers blood pressure and improves glucose metabolism. The improvements were similar to a moderate-intensity aerobic exercise programme that took fives times as long — ie, one minute of intense exercise broken up by two- to three-minute rest periods gave similar results to 50 minutes of moderate exercise.

    The implication is that an exercise session can benefit health in as little as 10 minutes. The low number of sprint repetitions required also makes this form of HIT more tolerable for the general population.

    There are some caveats. The studies conducted so far are small in number, small in size, and have measured only a handful of important health components. Studies have also tended to use cycling exercise, so access to equipment is a problem that needs addressing. There’s no question that more research is required.

    So, while all this research is going on, what sort of exercise should you be doing? Well, lots of different types of physical activity and exercise are helpful for our general health. The most beneficial is the one you do regularly. For some people that might be playing a sport, for some walking, and for those struggling for time the one-minute workout is certainly an option on the table.

    Dr Richard Metcalfe is a lecturer in exercise and health at Ulster University