Even a few minutes of gardening every day may prolong life for senior men, a new study suggests.
The Centers for Disease Control and Prevention (CDC) recommend that adults aged 65 and over engage in 150 minutes of moderate-intensity aerobic physical activity every week.
This should be in bouts of at least 10 minutes, they say.
Aerobic activity refers to any kind of exercise that improves the heart and the lungs. Some examples include brisk walking, running, swimming, and cycling.
In addition to the 150 minutes, the CDC also advise seniors to engage in muscle-strengthening activities on at least 2 days per week.
If moderate activity takes up too much time, these recommendations can be tweaked into vigorous-intensity equivalents, as detailed on the CDC website.
As the scientists mention in their new study, research has shown that people who regularly engage in moderate-level physical activity have a 20–30 percent lower risk of premature mortality compared with inactive adults, and the benefits seem to be greater as people age.
But such an amount of physical activity can be difficult to integrate, so researchers led by Dr. Barbara Jefferis, of the Department of Primary Care and Population Health at University College London in the United Kingdom, set out to examine whether even lower levels of exercise intensity affected the mortality risk in seniors.
Low levels of physical activity and aging men
So, Dr. Jefferis and her team used the British Regional Heart Study to recruit 1,181 male participants aged 78, on average, for their own research.
In 2010–12, the researchers asked these participants to wear an accelerometer — which is a device that measures the amount and intensity of physical activity — for 7 days.
The seniors were all physically examined and asked questions about their lifestyle, history of heart disease, and dietary and sleeping patterns. Individuals with a pre-existing heart condition were excluded from the study.
The participants were clinically followed for an average period of 5 years, during which time 194 of them died.
Overall, the study found that the total amount of physical activity correlated with a lower all-cause death risk. This included low-intensity physical activity.
Specifically, for each additional 30 minutes of light exercise per day, the all-cause mortality risk decreased by 17 percent. Such light-intensity activities included taking the dog out for a walk or gardening.
Additionally, the bouts of activity did not seem to make that much of a difference on lowering death risk: sporadic bouts of activity were linked to a 41 percent risk reduction, while bouts of 10 minutes or more correlated with a 42 percent lower risk.
The findings suggest that sporadic bouts of activity are a more achievable goal, as two thirds of the participants achieved their weekly total this way, whereas only 16 percent of the participants achieved their weekly goal in 10-minute bouts.
Even modest level activities are beneficial
The study authors also note a couple of limitations to their research. From the initial, larger pool of participants, those who agreed to wear accelerometers in the first place tended to have a more healthful lifestyle overall, so this may have biased the results.
A further limitation is the observational nature of the study, which means that no causality can be inferred from the results. Finally, it is not yet known whether the findings can be generalized to women.
However, as Dr. Jefferis and colleagues explain, "[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."
"Furthermore," they add, "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."