The less exercise you do, the more it matters

    11 January 2017

    ‘Weekend warriors’ — or people who get all their exercise in one session at the weekend — get almost as much benefit from it as those who exercise throughout the week, according to research published in the Journal of the American Medical Association.

    The study, using data from 63,000 adults in Britain over the age of 40, found that both groups lowered their risk of death by similar amounts.

    Those who spend at least 150 minutes a week doing moderate exercise, or 75 minutes a week doing vigorous exercise, were found to have a 35 per cent lower risk of death over an 18-year period than inactive adults.

    Those who crammed all of their exercise in at the weekend get similar health benefits, as long as they meet the same target. Their overall risk of death was 30 per cent lower. Men and women benefited equally, according to the study. (However, see our analysis below.)

    Gary O’Donovan, the lead author, said: ‘Weekend warriors are people who meet the recommended volume of physical activity each week through only one or two sessions. They are doing a large proportion of vigorous exercise and that makes you fitter than moderate exercise.

    ‘Millions of people enjoy doing sport once or twice a week, but they may be concerned that they are not doing enough. We find a clear benefit. It’s making them fit and healthy.’

    Instant analysis
    This is a paper conducted to investigate the impact of different patterns of exercise on all-cause mortality, cardiovascular disease and cancer. It was taken from 11 cohorts of data collected between 1994 and 2012 and then linked to mortality records.

    The paper began with the WHO recommendation of 150 minutes of moderate exercise a week or 75 minutes of vigorous aerobic exercise a week or equivalent combinations. (Intensity can be gauged on whether you can have a conversation while you do the exercise. If you can’t, it’s vigorous, not moderate).

    Participants were split into four groups. The ‘regularly active’ and ‘weekend warrior’ groups met the WHO recommendation — the latter did so in just one or two sessions a week, the former in at least three. The ‘insufficient’ group did exercise but did not reach the WHO recommendation. And then there was an ‘inactive’ group.

    At baseline, 63 per cent of participants were seen as inactive; 3.7 per cent were weekend warriors, and 11.1 per cent were regularly active.

    The study cited previous work at Harvard suggesting that exercise on only one or two days a week had a beneficial effect on mortality. But what struck me was the fact that this previous paper found mortality rates between ‘weekend warriors’ and the ‘insufficient’ exercise group to be almost exactly comparable and the mortality rate of the ‘inactive’ group to be about a third worse.

    However, its relatively low numbers of participants meant it did not have the statistical power to make this conclusion.

    The latest study found ‘weekend warriors’ to have lower mortality rates than the ‘insufficient’ exercising group. Thus the argument is that the data is moving towards an ‘L-shaped’ curve of effect, where significant improvements in mortality outcome can be derived from even light to leisure-like exercise on the weekend (the insufficient group); these improvements level off for ‘weekend warriors’ and then fall a little lower for the frequently active.

    Forget the ‘weekend warrior’: what the data shows, away from the hype, is that any form of exercise, even if infrequently done, seems to have a beneficial effect on health and mortality, irrespective of whether you are a weekend warrior on the football or hockey pitch or a solitary runner in your ‘mind tunnel’. The important thing is to keep it up.

    In my view (and that of colleagues) it is likely to be the dissipation of stress, the reduction of catecholamines (hormones such as epinephrine and norepinephrine) and the improvement of mental wellbeing that come with even small doses of exercise which are key to improving mortality and overall health.

    If you want to live longer, use your body for what it was designed to do: to move. Setting moderate, achievable goals in which exercise can be done long term as a matter of routine will offer the best results — and you don’t need to hack someone down with a hockey stick each weekend to do that.

    The limitations to the study were mainly around racial makeup, as 90 per cent of participants were white. It is therefore perhaps not generalisable. The data was self-reported, from a questionnaire, a system which is open to recall bias and notoriously unreliable. The study bracketed activities like housework as ‘light exercise’ – this seems to push up the ‘minutes of exercise done’ figure significantly to suggest that someone might be a prolific light to moderate exerciser when perhaps they just did the ironing.
    Research score: 3/5