Low-intensity physical activity — such as walking the dog or puttering about in the garden — is associated with a lower rate of premature death in older men, according to a study published online this week in the British Journal of Sports Medicine.

The study also suggests that it’s the total volume of physical activity, not necessarily the length of each exercise session, that matters — at least for older men.

That will be reassuring news for older people, who often find it difficult to meet current physical activity guidelines.

Most health experts recommend that people get a minimum of 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise each week. This new study suggests that, for older people, light-intensity “workouts” — even in short, sporadic bursts — may also be beneficial.

“All activities, however modest, are beneficial,” the study’s authors conclude. 

Study details

For the study, a team of British and American researchers recruited 1,181 men who were participants in the long-running British Regional Heart Study. The men had an average age of 78 in 2010-2012, when the recruitment began. None had a pre-existing history of heart disease.

When they joined the study, the men received a health checkup and filled out a detailed questionnaire about their health history and lifestyle habits. They were also asked to wear an accelerometer, which records the amount and intensity of physical activity, for seven days.

The men kept the accelerometers on their bodies for an average of 14 hours a day. The results of the recordings showed that they engaged in an average of 199 minutes of light activity and 33 minutes of moderate or vigorous activity each week.

The men were followed for an average of five years (up to June 2016). During that period 194 of them died. The researchers then analyzed the data they had collected to determine if the level of the participants’ activity at the start of the study was linked to their being alive when the study ended.

The analysis revealed a correlation between physical activity and the risk of death — even if the activity was low-intensity. 

Specifically, each additional 30 minutes a week of moderate- to vigorous-intensity exercise was associated with a 33 percent reduction in the risk of dying. No real surprise there. But the analysis also revealed a 17 percent reduction in the risk of dying for each additional 30 minutes a week of low-intensity physical activity — a finding that held even after taking into account confounding factors, such as the amount of time the participants spent being sedentary each week.

Nor did the study turn up any evidence that long sessions of intense physical activity are more beneficial than shorter ones. The researchers found that when the older men met the recommended goal of at least 150 minutes a week of moderate to vigorous exercise, they were about 40 percent less likely to die by the end of the study — whether they exercised in sessions that lasted shorter or longer than 10 minutes. 

Limitations and implications

The study comes with several caveats, including a major one: It was an observational study, which means no definite conclusions can be drawn from its findings.

In addition, the men from the British Regional Heart Study who agreed to wear the accelerometer and participate in this study tended to be younger and have healthier lifestyles than those who didn’t. They were also predominantly white. The study’s results may not apply, therefore, to younger men, other ethnicities — or to women.

Still, other studies have also suggested that shorter, less intense bouts of exercise may help people live longer lives. Such findings are “especially important among older men, as most of their daily [physical activity] is light intensity,” the authors of the current study note.

“Given the rapid decline in physical activity with age among the oldest old populations, encouraging even light activity may provide benefits for longevity,” they add.

FMI: You can download and read the study in full on the website of the British Journal of Sports Medicine.