Working up a sweat: It could save your life

The researchers followed 204,542 people for more than six years, and compared those who engaged in only moderate activity (such as gentle swimming, social tennis, or household chores) with those who included at least some vigorous activity (such as jogging, aerobics or competitive tennis).

They found that the risk of mortality for those who included some vigorous activity was 9 to 13 per cent lower, compared with those who only undertook moderate activity.

"The benefits of vigorous activity applied to men and women of all ages, and were independent of the total amount of time spent being active," said lead author Dr Klaus Gebel from James Cook University's Centre for Chronic Disease Prevention.

"The results indicate that whether or not you are obese, and whether or not you have heart disease or diabetes, if you can manage some vigorous activity it could offer significant benefits for longevity."

Co-author Dr Melody Ding from University of Sydney's School of Public Health, said the results indicated that vigorous activities should be more strongly encouraged in clinical and public health guidelines.

The current advice from the World Health Organization -- and health authorities in countries including the US, UK and Australia -- is for adults to accumulate at least 150 minutes of moderate activity or 75 minutes of vigorous activity per week.

"The guidelines leave individuals to choose their level of exercise intensity, or a combination of levels, with two minutes of moderate exercise considered the equivalent of one minute of vigorous activity," Dr Ding said.

"It might not be the simple two-for-one swap that is the basis of the current guidelines," she said.

"Our research indicates that encouraging vigorous activities may help to avoid preventable deaths at an earlier age."

The study classified participants into three groups: those who reported that none of their physical activity was at a vigorous level, and those who reported that up to 30 per cent or more of their activity was at a vigorous level.

The mortality rate for those who reported up to 30 per cent vigorous activity, was 9 per cent lower than those who reported no vigorous activity. For those whose exercise routine was vigorous for more than 30 per cent of the time, the rate of mortality was reduced by 13 per cent.

So who should get huffing and puffing, and how much do you need to do?

"Our research indicates that even small amounts of vigorous activity could help reduce your risk of early death," Dr Gebel said.

"For those with medical conditions, for older people in general, and for those who have never done any vigorous activity or exercise before, it's always important to talk to a doctor first.

"Previous studies indicate that interval training, with short bursts of vigorous effort, is often manageable for older people, including those who are overweight or obese."

The researchers investigated participants in the Sax Institute's 45 and Up study, which has collected baseline data on more than 267,000 men and women aged 45 and older, in the Australian state of New South Wales.

Dr Klaus Gebel is a Senior Research Fellow at the Centre for Chronic Disease Prevention at James Cook University in Cairns.

He commenced this study at the University of Sydney, and has completed it in collaboration with a team of University of Sydney researchers including Adrian Bauman, Sesquicentenary Professor of Public Health.

The paper, 'Physical activity and all-cause mortality in middle-aged and older Australians', is published online in the current edition of JAMA Internal Medicine.