Cardio exercises may help lower risk of flu or pneumonia death

People who indulge in brisk walking, swimming, running, and stair climbing can have significantly lower risk of death from flu or pneumonia, even at weekly levels below those recommended, suggests a research.

However, the findings published in the British Journal of Sports Medicine, showed there may be a level above which the effects plateau or - in the case of muscle strengthening activities - become potentially harmful.

Adults are advised to clock up at least 150 minutes/week of moderate intensity, or 75 minutes of vigorous intensity, aerobic physical activity, or an equivalent combination, plus muscle strengthening activity of moderate or greater intensity at least twice a week.

Muscle strengthening activities include the use of weights and resistance bands; exercises such as squats, lunges, and press-ups (callisthenics); and heavy gardening.

In the study, people who met both recommended weekly physical activity targets had nearly half (48 per cent) the risk of dying from flu or pneumonia as their peers who met neither, after accounting for potentially influential factors.

Meeting only the aerobic activity target was associated with a 36 per cent lower risk, after accounting for potentially influential factors, while meeting only the muscle strengthening target wasn't associated with any significant difference in risk.

"Although (10-150 minutes/week) is often labelled 'insufficient' because it falls below the recommended duration, it may confer health benefits relative to physical inactivity," suggest researchers from the US Centers for Disease Control and Prevention (CDC).

The team drew responses from 577,909 adults who had taken part in a national survey between 1998 and 2018. During an average monitoring period of nine years, 81,431 participants died; 1,516 of these deaths were attributed to flu and pneumonia.

People who clocked up 10-149, 150-300, and 301-600 minutes/week of aerobic physical activity were associated with, respectively, 21 per cent, 41 per cent, and 50 per cent lower risks, compared with none. But no additional benefit was seen above 600 weekly minutes.

When it came to muscle strengthening activities, compared with fewer than two weekly sessions, meeting the weekly target of two was associated with a 47 per cent lower risk, but seven or more sessions were associated with a 41 per cent higher risk.

This is an observational study, and as such, can't establish the cause, added to which the researchers acknowledge various limitations. For example, the study relied on personal recall and at one point in time.

Nevertheless, the researchers said, "Efforts to reduce influenza and pneumonia mortality among adults might focus on decreasing the prevalence of aerobic inactivity and increasing the prevalence of achieving two episodes/week of muscle-strengthening activity."