Research by Columbia University and an international team of scientists looked at data from six studies of more than 130,000 adults in the UK, US and Sweden.

The authors used a technique called compositional analysis to determine how different combinations of activities affect mortality – from moderate to vigorous exercise (activities that increase heart rate) and light physical activity (such as casual walking), to sedentary behaviour.

It found the benefits of 30 minutes of moderate to vigorous exercise depend entirely on how you spend the rest of the day.

Although the current recommendation of 30 minutes per day of moderate to vigorous physical activity reduced the odds of an earlier death by up to 80 per cent for some – those who sat for less than seven hours a day – it did not reduce mortality risk for individuals who were very sedentary (over 11 to 12 hours per day).

Breaking the cycle
Interestingly, the researchers identified multiple ways to achieve the same health benefits from exercise.

For example, people who spent just a few minutes engaging in moderate to vigorous physical activity lowered their risk of early death by 30 per cent – as long as they also spent six hours engaging in light physical activity.

“For decades, we’ve been telling people that the way to stay healthy is to get at least 30 minutes of exercise five days a week,” says Keith Diaz, PhD, assistant professor of behavioural medicine and director of the exercise testing laboratory at the Center for Behavioral Cardiovascular Health at Columbia University.

“But even if you’re one of the few adults who can stick to this advice, 30 minutes represents just two per cent of your entire day. – is it really possible that our activity habits for just two per cent of the day are all that matter when it comes to health?

“It’s not as simple as checking off the ‘exercise’ box on your to-do list, a healthy movement profile requires more than 30 minutes exercise a day. Moving around and not remaining sedentary all day also matters.”

Sebastien Chastin, PhD, professor of health behaviour dynamics at Glasgow Caledonian University in Scotland and lead author of the study, added: “Getting 30 minutes of physical activity per day, or 150 minutes per week, is what’s currently recommended, but you still have the potential to undo all that good work if you sit too long.”

The research was published in the British Journal of Sports Medicine.

More: www.HCMmag.com/30mins