Benefits of exercise greater if activity is of moderate intensity, study shows

Increasing your physical activity is good for your health, but the benefits are greater when more of it is of at least moderate intensity, a study suggests.

Researchers from Cambridge University and Leicester University analysed data from more than 88,000 middle-aged adults who wore a device on their wrist to measure their physical activity.

Participants wore the accelerometer on their dominant wrist for seven consecutive days as part of the UK Biobank study.

Researchers calculated the participants’ volume of activity, as well as the percentage of it that was of moderate intensity such as a brisk walk, and of vigorous intensity such as running.

They had recorded the number of cardiovascular events, including heart disease, among study participants over an average follow-up period of 6.8 years.

Higher total physical activity volume was strongly associated with a decrease in the risk of cardiovascular disease, according to the research.

Getting more of that physical activity from moderate to vigorous exercise was associated with a further reduction in cardiovascular risk.

Cardiovascular disease rates were 14% lower when moderate to vigorous physical activity accounted for 20% rather than 10% of the overall physical activity energy expenditure, even in those who otherwise had low levels of activity.

Overall, the lowest cardiovascular disease rates were observed among participants who undertook higher levels of physical activity and a higher proportion of at least moderate exercise.

However, when overall volume of physical activity increased but the proportion of at least moderate intensity activity remained the same, the authors observed little effect on cardiovascular disease rate.

Professor Tom Yates of Leicester University, one of the paper’s senior authors, said: “Our analysis of data from UK Biobank confirms that increasing the total amount of physical activity can lower the risk of suffering a heart attack or stroke, but we also found that achieving the same overall amount of physical activity through higher intensity activity has a substantial additional benefit.

“Our findings support simple behaviour-change messages that ‘every move counts’ to encourage people to increase their overall physical activity, and if possible to do so by incorporating more moderately intense activities.

The research highlighted the benefits of a brisk walk over a gentle stroll (PA)

“This could be as simple as converting a leisurely stroll into a brisk walk, but a variety of approaches should encourage and help individuals to find whatever is most practical or enjoyable for them.”

Current physical activity guidelines from the UK Chief Medical Officers recommend that adults should aim to be active every day, and undertake 150 minutes of moderate intensity activity or 75 minutes of vigorous intensity activity every week.

The paper’s first author Dr Paddy Dempsey, research fellow at Leicester University and Medical Research Council (MRC) Epidemiology Unit at Cambridge University, said many previous studies had relied on questionnaires to gather data.

This could be problematic, he said, as “physical activity intensity and duration is hard to recall accurately, especially when it comes to low intensity everyday activities like washing the car, or sorting laundry”.

He said the analysis of wearable device data demonstrates “moderate and vigorous intensity activity gives a greater reduction in the overall risk of early death”.

He added: “More vigorous physical activity may also reduce the risk of cardiovascular disease, over and above the benefit seen from the total amount of physical activity, as it stimulates the body to adapt to the higher effort required.”

The research is published in the European Heart Journal.