Vocabulary: physical activity 词汇：身体运动

Lack of exercise could be causing as many deaths around the world as smoking, according to an article in the science magazine The Lancet.

As thousands of Olympic athletes prepare to push their bodies to the limit, most of us sit inactive for hours in front of a TV set.

But the scientists say they are not suggesting difficult gym sessions. As Pamela Das from The Lancet puts it: "It is not about running on a treadmill, whilst listening to your iPod."

The aim is to encourage everyone to think about fitness and build physical activity into their daily lives, such as brisk walking, gardening or any energetic pursuit.

Despite the familiarity of the message, one in three adults worldwide fails to do the recommended 150 minutes of moderate aerobic physical activity per week.

So, rather than stressing the health benefits of a good workout, The Lancet researchers have decided to show the harm caused by inactivity. They estimate lack of exercise is responsible for about 5.3m deaths a year: about the same number as smoking.

Sitting around doing nothing can lead to coronary heart disease, Type 2 diabetes, and breast and bowel cancers.

The data might lack muscle as scientists have had to rely on questionnaires sent out to 122 countries in which people report their own levels of activity. It must also be difficult to separate the impact of obesity from the figures.

But Dr I-Min Lee, from Harvard Medical School, says they were very cautious: "Our estimates of ill-health from lack of physical activity are on the low side."

The researchers say the problem of inactivity has reached pandemic levels, with far-reaching health and social consequences. They call for a radical re-think in how to deal with the issue.