Body Work

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Too much sitting is bad for your health
Our public health advisers tell us to exercise for just 30 minutes a day. But a recent study on television viewing time and mortality published in Circulation suggests that’s only part of the solution to the obesity problem, as the human body was designed to keep moving, not sit for extended periods of time.

Australian researchers at the Baker IDI Heart and Diabetes Institute in Australia tracked the TV viewing habits of 8800 adults in Australia (age 25 and older) over 6 years and found that compared with people who watched less than two hours of television daily, those who watched more than four hours a day had a 46% higher risk of death from all causes and an 80% increased risk for CVD-related death they report. This association held regardless of other independent and common cardiovascular disease risk factors, including smoking, high blood pressure, high blood cholesterol, unhealthy diet, excessive waist circumference, and leisure-time exercises.

Associate Professor David Dunstan
Associate Professor David Dunstan

‘It’s not the sweaty type of exercise we’re losing,’ says Prof. David Dunstan, a leading researcher on the role of physical activity in the prevention and management of type 2 diabetes. ‘It’s the incidental moving around, walking around, standing up and utilizing muscles that doesn’t happen when we’re plunked on a couch in front of a television.’ In fact, the study participants typically reported getting between 30 and 45 minutes of exercise a day.

‘What has happened is that a lot of the normal activities of daily living that involved standing up and moving the muscles in the body have been converted to sitting,’ Dunstan said. ‘People don’t move their muscles as much as they used to – consequently the levels of energy expenditure as people go about their lives continue to shrink. For many people, on a daily basis they simply shift from one chair to another – from the chair in the car to the chair in the office to the chair in front of the television. Even if someone has a healthy body weight, sitting for long periods of time still has an unhealthy influence on their blood sugar and blood fats,’ he said. The implications are simple, Dunstan said. ‘In addition to doing regular exercise, avoid sitting for prolonged periods and keep in mind to ‘move more, more often’. Here are David’s tips for moving more:

  • Switch off, stand up and get moving
  • Avoid prolonged periods of sitting – whether in front of the TV, a computer screen or on transport. At the very least get up and move once every hour
  • Limit your TV viewing to two hours a day
  • Use commercial breaks for household chores
  • Stand up and move around while answering the telephone