Just a few minutes of light intensity exercise linked to lower death risk in older men
Clocking up just a few minutes at a time of any level of physical activity, including of light intensity, is linked to a lower risk of death in older men, suggests research published online in the British Journal of Sports Medicine.
Providing the recommended 150 minute weekly tally of moderate to physical activity is reached, total volume, rather than activity in 10 minute bouts, as current guidelines suggest, might be key, the findings indicate.
This lower level of intensity is also likely to be a better fit for older men, most of whose daily physical activity is of light intensity, say the researchers.
Current exercise guidelines recommend accumulating at least 150 minutes a week of moderate to vigorous physical activity in bouts lasting 10 or more minutes. But such a pattern is not always easy for older adults to achieve, say the researchers.
To find out if other patterns of activity might still contribute to lowering the risk of death, the researchers drew on data from the British Regional Heart Study.
This involved 7735 participants from 24 British towns, who were aged between 40 and 59 when the study stated in 1978-80.
In 2010-12, the 3137 survivors were invited for a check-up, which included a physical examination, and questions about their lifestyle, sleeping patterns, and whether they had ever been diagnosed with heart disease.
They were also asked to wear an accelerometer—a portable gadget that continuously tracks the volume and intensity of physical activity—during waking hours for 7 days. Their health was then tracked until death or June 2016, whichever came first.
In all, 1566 (50%) men agreed to wear the device, but after excluding those with pre-existing heart disease and those who hadn't worn their accelerometer enough during the 7 days, the final analysis was based on 1181 men, whose average age was 78.
During the monitoring period, which averaged around 5 years, 194 of the men died.
The accelerometer findings indicated that total volume of physical activity, from light intensity upwards, was associated with a lower risk of death from any cause.
Each additional 30 minutes a day of light intensity activity, such as gentle gardening or taking the dog for a walk, for example, was associated with a 17 percent reduction in the risk of death. This association persisted even after taking account of potentially influential lifestyle factors, such as sedentary time.
Whilst the equivalent reduction in the risk of death was around 33 percent for each additional 30 minutes of moderate to vigorous intensity physical activity a day, the benefits of light intensity activity were large enough to mean that this too might prolong life.
And there was no evidence to suggest that clocking up moderate to vigorous activity in bouts of 10 minutes or more was better than accumulating it in shorter bouts. Sporadic bouts of activity were associated with a 41 percent lower risk of death; bouts lasting 10 or more minutes were associated with a 42 percent lower risk.
Sporadic bouts seemed easier to achieve as two thirds (66%) of the men achieved their weekly total of moderate to vigorous physical activity in this way while only 16% managed to do so in bouts of 10 or more minutes.
Finally, there was no evidence to suggest that breaking up sitting time was associated with a lower risk of death.
This is an observational study so no firm conclusions can be drawn about cause and effect. And those who wore the accelerometer tended to be younger and have healthier lifestyles than those who didn't, so this might have skewed the results, say the researchers. Nor is it clear if the findings would be equally applicable to younger age groups or older women.
Nevertheless, the results could be used to refine current physical activity guidelines and make them more achievable for older adults, suggest the researchers.
Future guidance might emphasise that all physical activity, however modest, is worthwhile for extending the lifespan—something that is particularly important to recognise, given how physical activity levels tail off rapidly as people age, they point out.
"[The ] results suggest that all activities, however modest, are beneficial. The finding that [low intensity physical activity] is associated with lower risk of mortality is especially important among older men, as most of their daily physical activity is of light intensity," write the researchers.
"Furthermore, the pattern of accumulation of physical activity did not appear to alter the associations with mortality, suggesting that it would be beneficial to encourage older men to be active irrespective of bouts," they add.
More information: Barbara J Jefferis et al. Objectively measured physical activity, sedentary behaviour and all-cause mortality in older men: does volume of activity matter more than pattern of accumulation?, British Journal of Sports Medicine (2018). DOI: 10.1136/bjsports-2017-098733