The best time to jog outdoors is not the early morning, as most people think.

"Although many people feel full of energy in the beginning of the day, actually the perfect time to jog or exercise is 5-6pm," says Lu, "because the body temperature is the highest of the whole day. That promotes energy circulation."

Active oldster

Chen Shufeng, 77, gets up at 5am every day, walks to the park to meet other seniors and moves about. They do morning exercises and sometimes dance for a while. She eats breakfast when she returns home.

"We mainly stretch our bodies, arms and legs," says Chen.

From expert

It's essential for old people to do some soft sports like walking or slow dancing. But they shouldn't go out too early or in very cold weather that may injure elders' weaker windpipes and hurt heart and lung functions.

Exercising in very cold weather is not advised for people with high blood pressure.

On the other hand, contrary to what many people think, it's not a good idea to exercise too early in a park that has lots of greenery. There's not enough oxygen before sunrise when green plants consume lots of oxygen and release carbon dioxide.

The best time for old folks' morning exercise is 8-11am, says Lu.

Besides, exercising on an empty stomach isn't good for anyone's health, whether they're young or old.

Eating half an hour before exercise gives you energy and makes the exercise more effective.

Energetic youth

Nie Yizhong, 18, doesn't seem to notice the cold. Almost every afternoon after school, he plays basketball with classmates, on weekends he goes to Xujiahui Park near his home.

Although rain or frost may keep him indoors, he still exercises.

"At school, we do morning exercises every day; in regular PE classes, we do something like running, skipping," he says.

From expert

Keep it up, you're doing great. The problem may lie in overdoing it, not in underdoing it.

In all seasons, especially winter, it's important to warm up well and stretch before getting started, especially for running, football and basketball.

"As the bones and muscle are less flexible and pliable due to cold weather, it's easier to hurt ankles and muscles without a proper warm-up," says Lu Dajiang, a body-building expert from the Shanghai Sports Academy.

Young healthy people should also protect the throat and windpipe, so as not to cause injury to the heart and lungs, he says. Dress warmly.

(Shanghai Daily December 23, 2008)