Sedentary behaviour trumps obesity as a killer

If you had but one New Year’s resolution to keep, maybe it should be to get up and move a little more. Yet another study shows that a sedentary lifestyle is the ‘new smoking’.

New research shows that for men and women across the spectrum of body mass index and belt size, those who got even a little exercise – burning up about 100 calories a day in physical activity – were less likely to die of any cause over a 12-year period than those who were entirely sedentary.

In a large and diverse European population, the new study suggests that physical inactivity might be responsible for twice as many total deaths as having a high body mass index. But it found that having a high waist circumference too – a surrogate measure for abdominal obesity – was nearly as powerful a predictor of premature death as was inactivity.

Using 2008 European death figures, the authors suggested that 676,000 of 9.2 million deaths could be attributed to physical inactivity. By contrast, 337,000 deaths could be attributed to obesity. In the population studied, 22.7% reported they got virtually no regular physical activity. Obesity affected 15.8% of participants, and 21.9% were considered abdominally obese because they had a waist circumference greater than 35 inches for a woman or 40 inches for a man.

The study, which tracked 116,980 men and 217,181 women throughout Europe for an average of 12 years, was published in the American Journal of Clinical Nutrition.

For all of physical activity’s protective powers, however, the latest research underscores that it works best for men and women who can keep their BMI in the “normal healthy weight” category. Those whose BMI falls between 18.5 and 24.9 benefited most when their routine included at least a modicum of exercise.

Compared with lean but sedentary folk, lean people who were even “moderately inactive” were, on average, 30% less likely to die of any cause during the study’s follow-up period. Moderately active slim people were 36% less likely to die than were their sedentary but slim peers. And “active” slim people were 41% less likely to expire over the 12-year period.

For those in the obese category – with BMIs over 30 – the findings were not as reassuring. Other studies have established that obesity alone raises the risk of death due to any cause. In the current study, those who exercised even a little were just 20% less likely to die during the study than were sedentary obese people, and those considered “moderately active” were at 27% less risk of dying. Obese people at the highest physical activity levels – considered “active” – were 21% less likely to die than their sedentary peers. For the obese, the study suggests, moderate exercise may be best.

The benefits of exercise for reducing the death risk in overweight people – those with a BMI between 25 and 30 – lay in the middle.

By far the best returns on an investment in exercise clearly came to those who were deemed “moderately inactive”: compared with people of all shapes and sizes who were entirely sedentary, those that got just a little physical activity – a brisk 20-minute walk or a short bicycle ride daily – saw the most dramatic reductions in their risk of dying.

That “suggests that even small efforts to encourage small increases in activity in inactive individuals may be of public health benefit,” wrote the authors, a team of researchers from Denmark, Sweden, Norway, France, the Netherlands, Spain, Greece, Britain, Italy, Germany and the United States.

Source: LA Times