By Jasminee Sahoye

A study among elderly men has found that 30 minutes of physical activity – irrespective of intensity – six days a week is linked to a 40% lower risk of death from any cause.

Researchers based their findings on people taking part in the Oslo Study, which invited almost 26,000 men born between 1923 and 1932 for a health check in 1972-73.

Some 15,000 agreed. Their height, weight, cholesterol and blood pressure were all assessed and they were asked if they smoked.

They were also asked to respond to a validated survey on their weekly leisure-time physical activity levels. These were categorized as sedentary (watching TV / reading); light (walking or cycling, including to and from work for at least four hours a week); moderate (formal exercise, sporting activities, heavy gardening for at least four hours a week); and vigorous (hard training or competitive sports several times a week).

Almost 6,000 of the surviving men repeated the process in 2000 and were monitored for almost 12 years to see if physical activity level over time was associated with a lowered risk of death from cardiovascular disease, or any cause, and if its impact were equivalent to quitting smoking.

During the monitoring period, 2,154 out of the 5,738 men who had gone through both health checks died.

Analysis indicated that less than an hour a week of light physical activity was not associated with any meaningful reduction in risk of death from any cause. But more than an hour was linked to a 32% to 56% lower risk.

Less than an hour of vigorous physical activity, on the other hand, was linked to a reduction in risk of between 23% and 37% for cardiovascular disease and death from any cause.

The more time spent doing vigorous exercise the lower the risk seemed to be, falling by between 36% and 49%. And men who regularly engaged in moderate to vigorous physical activity during their leisure time lived five years longer, on average, than those classified as sedentary.

Factoring in the risk of death from heart disease / stroke rising with age made only a slight difference to the results. Overall, these showed that 30 minutes of physical activity – of light or vigorous intensity – six days a week was associated with a 40% lower risk of death from any cause.

The impact would seem to be as good for health as quitting smoking among this age group, suggest the researchers.

This is an observational study so no definitive conclusions can be drawn about cause and effect and the researchers point out that only the healthiest participants in the first wave of the study took part in the second wave, which may have lowered overall absolute risk.

Another study states that exercise of short duration and low intensity has life expectancy benefits for the elderly. Such conclusions have been well examined in the general population where a recommended exercise program of 30 minutes at least five days a week (150 minutes per week) has been shown to reduce the average risk of death by 30%.

A study in a French cohort of more than 1,000 elderly subjects has found a negative correlation between their level of physical activity and risk of all-cause death, suggesting that in the elderly (as in other population groups) the risk of death decreases with greater and more regular exercise.