Inactivity 'killing as many as smoking'

A lack of exercise is now causing as many deaths as smoking across the world, a study suggests.

The report, published in the Lancet to coincide with the build-up to the Olympics, estimates that about a third of adults are not doing enough physical activity, causing 5.3m deaths a year.

That equates to about one in 10 deaths from diseases such as heart disease, diabetes and breast and colon cancer.

Researchers said the problem was now so bad it should be treated as a pandemic.

And they said tackling it required a new way of thinking, suggesting the public needed to be warned about the dangers of inactivity rather than just reminded of the benefits of being active.

The team of 33 researchers drawn from centres across the world also said governments needed to look at ways to make physical activity more convenient, affordable and safer.

It is recommended that adults do 150 minutes of moderate exercise, such as brisk walking, cycling or gardening, each week.

Physical inactivity is recognized as an important risk factor for multiple causes of death and chronic morbidity and disability.

Physical activity was chosen rather than physical fitness as the measure of exposure because it is through increases in the behaviour (physical activity) that health benefits accrue and improvements in cardiorespiratory fitness can be achieved. Moreover, there were insufficient data available worldwide to consider fitness as the exposure.

Exposure was assessed as a trichotomous variable to avoid limiting the assessment of total burden to only that associated with the highest risk, namely the most inactive (a dichotomous approach). However due to a lack of data on physical inactivity, use of a more detailed (continuous) exposure variable was not possible nor was the use of a fourth category of 'high activity'. Therefore, our estimates of burden are likely to underestimate the total attributable burden to inactivity because of limitations with measures of exposure. Level 1 exposure (inactive) was defined as “doing no or very little physical activity at work, at home, for transport or in discretionary time”. Level 2 exposure (insufficiently active) was defined as “doing some physical activity but less than 150 minutes of moderateintensity physical activity or 60 minutes of vigorous-intensity physical activity a week accumulated across work, home, transport or discretionary domains”.

We found a wide range of survey instruments and methodologies have been used for collecting, analysing and reporting data on physical activity. Most data were available for discretionary-time activity, some data were found on occupational activity and little and no national data were available for transport- and domestic-related activity, respectively. A comprehensive literature search and contact with key agencies and known researchers uncovered over 50 data sets on physical inactivity in adult populations covering 43 countries across 13 subregions.