How much exercise do you need?

Good Health magazine

Monday, May 21, 2012

Doing the sums: how much exercise does your body need? Image: Thinkstock

While 30 minutes is enough to keep you healthy, studies say you need nearly twice that to keep you thin.

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You need 30 minutes of exercise each day to keep you healthy, but twice as much to keep you thin. Helen Foster does the sums to find out how much exercise we really need.

If you want to: use exercise to keep weight off
Then do: 55 minutes of moderate exercise five times a week. Why? While 30 minutes is enough to keep you healthy, studies say you need nearly twice that to keep you thin. University of Pittsburgh researchers found women who’d successfully lost weight and kept it off for two years burnt about 7707kJ a week through exercise — to achieve this you need about 275 minutes of moderate exercise. But they weren’t sweating it out at the gym to do it, according to the study’s author Professor John Jakicic. Walking was the most common workout the successful women used — probably because 55 minutes of walking is easier to build into your day regularly than a specific gym visit.

If you want to: Use exercise to help you sleep
Then do: 30 minutes of any exercise first thing in the morning.

Why? Trials at the Appalachian State University in the US found people exercising for 30 minutes at 7am slept better than those working out at lunchtime or 7pm. In fact, they spent 75 per cent more time in deep sleep and 85 per cent more in light sleep than those who exercised at other times. “We think this occurs because working out first thing attenuates the rise in the stress hormone cortisol that occurs to wake you up in the morning,” says study author, Professor Scott Collier. Because of our stressful lives, this can stay high throughout the day, making it harder to fall asleep at night and creating a more fitful sleep when you do.

If you want to: Use exercise to lift your mood
Then do: An AM exercise class.

Why? Even just 17 minutes of walking daily has been shown to slash symptoms of depression by 41 per cent. But for the biggest boost, schedule your exercise first thing in the morning. When researchers at the UK’s University of Glasgow measured post-exercise highs, they found that while evening workouts revved up mood by 19 per cent, morning workouts raised it by 48 per cent. “That doesn’t surprise me,” says Nathan Maurice from Oz Bootcamp. “For some people, it’ll be because they wake up full of beans and so get an extra buzz from their morning efforts. For people who don’t like mornings or exercise, it’ll be a mix of a sense of achievement and relief that they’ve got their workout done for the day!”