(shanghai daily)
Updated: 2007-01-30 09:03

Many people are attracted to winter swimming for health reasons. There are reports of winter swimming alleviating asthma, rheumatism and heart conditions, but we also hear of people taking ill or dying from sudden changes of temperature.

Is winter swimming really that good for you? Can anyone start winter swimming? What should winter swimmers be careful about?

To answer these questions, Shanghai Daily interviewed Dr Zhang Suzhen, senior body-building expert and professor in the Sports Medicine Department of the Shanghai Sports University.

According to Dr Zhang, winter swimming, generally known as "the exercise for blood vessels," does have a positive effect on bloods vessels. The mechanism is simple. Change of temperature from water to land encourages expansion and contraction of blood vessels, meaning they get more exercise.

Therefore, winter swimming does help to keep blood vessels healthy, which helps with circulation and can help with many conditions.

However, winter swimming is not a sport for everyone.

It requires a physical examination to exclude those with serious heart conditions or high blood pressure. Dr Zhang does not recommend major exercise because it could cause more severe problems. People should consult their own physicians.

Second, nobody should plunge in right away and start winter swimming immediately. Winter swimmers are all regular swimmers who swim year around. The rare cases of sudden death during winter swimming are usually non-regular swimmers who couldn't tolerate the abrupt change of temperature.

Swimmers should also do warm-up exercises before jumping into the cold water, usually two to four degrees Celsius.

"It is extremely important to have a qualified coach for winter swimming. Everyone has a different tolerance and the coach can decide how much time and how many meters one can swim in the cold water according to their different conditions," says Dr Zhang.

He suggests that beginners stay in the water for only a few minutes and gradually build up. But nobody should swim for more than 30 minutes in the winter.