It's official: you've got to work up a sweat

BBC 《衛報》報道，英國政府發出健康指引，打掃家居、步行到市場買菜等對增強體魄無甚作用，要強身健體，人們應該每天做起碼大約30分鐘的柔軟體操。

報道說，科學界、負責公共健康的決策者希望按照世界衛生組織的標準，澄清什麼才是運動。

The era of gentle exercise is over. It's official: you've got to work up a sweat

Polly Curtis, health correspondent
Friday August 17, 2007
The Guardian

Runners in the London Marathon. Adults are now being told they need regular vigorous exercise. Photograph: Rebecca Naden

Official advice that 30 minutes of gentle exercise a day is enough to improve your health has been revised by the scientists who first developed the international fitness guidelines.

Until now, government recommendations have suggested that people can achieve a minimum level of fitness through their normal daily routines. But amid fears that the lightest of activities such as dusting and the stroll to the car are being counted as exercise, a new study by the public health experts behind the formula concludes adults need to add jogging and twice-weekly weight training sessions if they want to cut their risk of heart disease and obesity.

The scientists, world-leaders in public health and exercise advice, say they want to clarify the fitness guidelines for healthy adults which were adopted by the World Health Organisation and later used as a template for healthy living by the UK government. Some people have misunderstood the original message and are doing too little exercise, they argue. But they go even further saying explicitly that people should do vigorous as well as moderate aerobic exercise because of the "substantial science base" that it is good for you.

The paper published in Circulation, the journal of the American Heart Association, includes authors who are influential members of the American College of Sports Medicine. They write: "There are people who have not accepted, and others who have misinterpreted, the original recommendation. Some people continue to believe that only vigorous intensity activity will improve health while others believe that the light activities of their daily lives are sufficient to promote health."

The new guidelines say:

· 30 minutes of moderate exercise a day is still the minimum, but vigorous as opposed to moderate activity should be "explicitly" recommended

· Combining days of moderate exercise with other days of vigorous exercise is better for you

· Moderate exercise should be in addition to daily activities such as casual walking, shopping or taking out the rubbish

· People should do two weight-training sessions a week

· Adults over 65 or those who are infirm during their 50s and early 60s should also do balancing exercises if they are at risk of falling and draw up appropriate exercise plans with their doctors.

"Many adults, including those who wish to improve their personal fitness or further reduce their risk of premature chronic health conditions and mortality related to physical inactivity, should exceed the minimum recommended amounts of physical activity," it says.

But their apparent change of heart exposes the dilemma facing health officials of how to encourage an increasingly overweight population to exercise without deterring them with over-ambitious programmes. Anti-obesity experts suggested that advising people to do weight-training was unrealistic.

David Haslam, chair of the National Obesity Forum, said: "If you suggested everyone here should do weight-training twice a week they wouldn't do it. They don't have the time or money for the gym, it would be an unrealistic guideline. I'd rather see healthy habits built into daily life - gyms aren't a sustainable habit."

Paul Gately, professor of exercise and obesity at Leeds Metropolitan University, said: "Scientists keep changing the goalposts but this advice is trying to provide more specific information for specific groups of people to encourage them to do appropriate exercise.

"It's the age-old problem of one-size-fits-all public health advice versus tailored programmes. People who are very overweight would have to do an hour of exercise a day just to maintain their weight if they aren't going to change their diets."

The authors include several experts who are on a high-level committee in the US which next year will announce America's new physical activity guidelines. Their revisions this month are widely expected to be adopted as official advice there. Their original recommendations in 1995 were quickly adopted by the WHO and by the UK government in 1996.

In 2004 the chief medical officer for England and Wales, Sir Liam Donaldson, republished the recommendations in his attempt to underscore the importance of more rigorous exercise and show that people could achieve the total through smaller 10-minute chunks. It was revealed then that up to two-thirds of men and three-quarters of women were failing to meet the 30-minute goal. Scotland's advice is similar to that in England and Wales.

A spokeswoman for the Department of Health said it was watching developments in the evidence about how much exercise was optimum but there were no plans at the moment to change the advice.