There’s a new study out, based on research from Taiwan, that shows that exercising for just 15 minutes a day (about 1.5 hours a week) is associated with a 14 per cent reduced risk of death over a the course of the study compared with being sedentary [1]. This study is wildly being reported as evidence that even low levels of activity (lower than generally recommended) can delay death. Much that I would like this to be so, from a scientific standpoint, this is a conclusion too far, I think.
The reason for this is that the study in question is what is known as ‘epidemiological’ in nature, which means it is assessing associations between things (in this case, exercise habits and risk of death over time). Associations, though, do not prove causality. We don’t know from these sort of studies if exercise is having a direct positive impact on health. It might, for example, be the other way round. Maybe individuals who are healthier are more inclined to exercise. Maybe being sedentary is a sign of sickness. Basically, we just don’t know. All we know is that even low levels of activity is associated with reduced risk of death.
That said, in my heart (more than my head) I believe that even relatively low levels of activity is indeed likely to benefit health and stave off death. I see activity and exercise as a pillar of health. Long-term studies which randomise people exercise or non-exercise groups and then follow them until death (to see if exercise actually reduces death risk) do not exist. However, we do have shorter-term studies that show improvements in terms of disease markers. These are changes we would expect to translate into reduce risk of disease (and perhaps death) in time.
Also, with exercise, I think there is a ‘law of diminishing returns’. Let’s say you exercise for an hour each day. How much more is to be gained from exercising for say, an hour and 15 minutes? The incremental benefit is likely to be small in comparison to the benefit had from exercising for an hour.
However, if we go from no activity (sedentary behaviour) to 15 minutes of daily exercise, the relative benefit is likely to be huge in comparison. This is one of the reasons I encourage normally sedentary individuals to do something.
In my last book – Waist Disposal – I included a brief, home-based exercise session made up of mix of resistance exercises (like press-ups, sit-ups and squats) and more aerobic exercise (running on the spot). The session is designed to be 12 minutes long. Compared to doing nothing, this brief session can do wonders for improving strength and physique, and I believe it likely impacts positively on health too. This sort of regime is unlikely to allow us to qualify for next year’s Olympics, but I believe it’s impact on health and wellbeing can be profound.
Tack this sort of regime on to recreational walking and perhaps some stretching, and I believe our exercise ‘needs’ will be largely met.
This new study from Taiwan tells us very little about the purported benefits of exercise, and I think its findings have been overstated. However, I utterly support its message: devoting even small amounts of time to activity and exercise is much, much better than doing nothing.
References:
1. Chi Pang Wen, et al. Minimum amount of physical activity for reduced mortality and extended life expectancy: a prospective cohort study. The Lancet, Early Online Publication, 16 August 2011
I avidly read Dr Kenneth Cooper’s book Aerobics (1968) which said one must attain 60-80% of one’s maximum heart rate then keep it there for 20 min to have an “effect” (increase O2 uptake) and I followed that principle for a long time.
But, over the years exercise gurus have steadily backed away from the aerobics principle, reducing effort and time spent in exercise. Even the good doctor Cooper backed away from his own study saying much less will still be beneficial. I believed him the first time and thought he had turned traitor…he had invalidated his original research.
Now we’re saying that couch potato-to-15 min of walking is a huge gain. Was Dr Cooper’s original research wrong?
I used to go out of my way to exercise, like a trip to the gym or pool, but found aspects of life could result in a lapse in my will and ability to visit.
People differ, of course, but I think making activity intrinsic to daily business, like walking to a nearby destination or alighting from public transport a stop early, can be beneficial and is more ‘sustainable’ or ‘attainable’ if is established as habit.
I feel a little pleased with myself as I’ve commenced cycling the 13 miles e/w to work and despite having been fairly inactive for a couple of years I am surprised (one) how much I enjoy it and (two) how much the exercise impacts upon the way I feel for the better! The trip takes about 50 minutes by bike and would have taken around 25 by car. I get a net workout of 50 minutes that ‘costs’ only 25 minutes of my time, whereas tripping to the gym would require around 90 minutes of my time.
I used to exercise with fair intensity but I’ve altered my view. Intensity can add to general wear and tear whereas incorporating self-locomotion into the daily routine can be less intense and less damaging -plus it saves fuel, fares, and/or gym fees.
If aspects of lifestyles, perhaps stress, inactivity, or sub-optimal dietary choices, lead to degrees of dys-regulation within the body knocking regulatory systems off axis, I am sure even moderate measures of habitual exercise go some way to restoring balance to the marvellous and bewildering process of biochemical regulation. Exercise can relieve mental stress and anxiety, work off glycosylation, reduce glycogen reserves, and ease the load on insulin, I’d guess. It clears my head and puts a spring in my step. Listen to your body, it is giving you it’s diagnosis.