How much physical activity should we undertake?

If you exercise, you are three times more likely to report positive mental health, study shows

The first published study to show that physical activity can reduce cardiovascular disease appeared in the November 28th, 1953, issue of the Lancet medical journal. It reported that London bus drivers had twice the incidence of coronary heart disease than their more active bus conductor colleagues.

Since then, many studies have confirmed the physical health benefits of exercise, and the adverse effects of physical inactivity. For example, in Ireland, physical inactivity is responsible for 9 per cent of cases of coronary heart disease; 11 per cent of type 2 diabetes; 15 per cent of breast cancers; and 16 per cent of colon cancers. This is cited by the authors of a recent major Irish study into the mental health benefits conferred by undertaking physical activity.

Their study of 7,539 Irish adults, entitled Physical activity and mental health in an Irish Population, found that the physically active are more likely to report experiencing positive mental health than negative mental health. Specifically, the report in the Irish Journal of Medical Science, based on data from the Healthy Ireland Survey, published in July this year stated that "compared with those who reported meeting recommended physical activity requirements, those performing no physical activity were three times less likely to report positive mental health . . . and three times more likely to report negative mental health".

Recommended levels

So, how much physical activity should we undertake? According to lead author Dr Andrea Bowe, specialist registrar in public health medicine, the recommended level of physical activity for an average adult is a minimum of 30 minutes of moderate physical activity, meaning an increase in heart rate and breathing to the extent that one can still converse, performed at least five days a week. However, she emphasises that "any activity is better than none and there are huge health benefits to be gained by any increase in physical activity for those who are unable to do 30 minutes of activity".


Bowe’s team found a greater prevalence of reported negative mental health among females: “We noted a significant gender gap between the proportion of females who were highly active (24 per cent) compared with males (40 per cent). We also found that negative mental health was significantly more prevalent among women, with a prevalence of 13 per cent, compared with 6 per cent in men.”

A finding, Bowe explains, that is consistent with international studies.

If exercise could be packaged in a pill, it would be the single most widely prescribed and beneficial medicine in the nation

Bowe says biomedical, psychosocial and societal factors can contribute to negative mental health. “However,” she adds, “we found even after statistically adjusting for some of these factors including age, social class and educational level, women who engage in high levels of physical activity are more likely to report better mental health.”

To address the gender gap in exercise participation, the Irish Sports Council launched the Women in Sport Initiative in 2005, and Bowe reports encouraging results: "Data from the Irish Sports Monitor, a population study which tracks adult participation in sport, suggest the initiative is having an impact, as female participation in sport is increasing and the gender gap appears to be narrowing."


What policy changes could improve the situation described in this report, and what are the main barriers to their implementation? “Steps have been taken to try to increase physical activity levels in Ireland,” says Bowe, “and the introduction of our first National Physical Activity Plan in 2016 was a positive step in recognising the importance of sport and exercise participation.”

She is also clear that the main reported barrier to engaging in physical activity is that people are too busy.

“Therefore,” she says, “we need to focus on how we can incorporate exercise into daily routines: areas such as active travel and workplace approaches. This requires a collaborative approach and may include policies aimed at improving cycle paths, walkways and access to green space. Prolonged sitting isn’t healthy, so try to increase activity throughout the day: walk or cycle to work, take the stairs, try incorporating a social element to exercise such as catching up with friends over a walk or jog in the evening.”

Bowe further emphasises their finding that those meeting recommended physical activity targets are more likely to have positive mental health and less likely to have negative mental health: “Our results suggest engaging in the recommended levels of physical activity may also help achieve one’s optimal level of wellbeing. While many of the factors that influence our mental health, such as genetics and socio-cultural factors are non-modifiable, physical activity represents a behaviour that can be modified to improve mental health.”

Valuable resource

Exercise, says Bowe, can be performed anywhere at any time: “If we can re-frame how we think about exercise and not consider it as a daily burden but a valuable resource available to us all, it could improve both our physical and mental health.”

Finally, Bowe quotes the late American psychiatrist and ageing expert Dr Robert N Butler: "If exercise could be packaged in a pill, it would be the single most widely prescribed and beneficial medicine in the nation."

As an increasing wealth of evidence makes clear, if we are to take responsibility for our own physical and mental health, we must accept that making a commitment to undertake regular exercise is a basic requirement.