Exercise is generally touted as being good for the lungs. But intensive training - especially in cold dry atmospheres - can have the opposite effect, according to worldwide lung experts meeting in Florence last month (September). The following alarming recent findings were presented to the World Congress on Lung Diseases:

* A survey of 1600 top athletes in Norway showed that no fewer than one in every 10 suffers from asthma or wheeze;
* In a questionnaire survey carried out after the 1996 Olympics in Atlanta, 16% of 700 athletes reported suffering from asthma. Worst affected were the cyclists, where the proportion rose to 50%;
* A Finnish survey of 58 marathon runners showed that 26% showed signs of bronchial contraction, either in the spring (because of hay fever) or in winter because of the cold. A study by the same research group of 71 long- distance runners found their risk of asthma was three times higher than average;
* US Researchers found that more than a quarter of the athletes on the American team at the 1998 winter Olympics suffered from bronchospasms. Most at risk of this problem were cross-country skiers, of whom 50% were affected.

Intensive training and cold dry atmospheres seem to be the main culprits - although swimmers suffer from asthma-related symptoms for quite specific reasons connected with chlorine inhalation.

Professor Kai-Hakon Carlsen of Sweden reported to the meeting that the proportion of asthmatics among 20-year-old cross-country skiers is only 7%, compared with 20% for those over 30.

But Swedish skiers, who train in cold, dry atmospheres, are more at risk of asthma than their Norwegian counterparts, who train near the coast in more humid conditions.

Physical activity is more likely to cause asthma in winter because of the effects on the lungs of processing ice-cold air.

The risk of lung damage can be averted or minimised by use of a mask covering the nose and mouth, enabling exhaled air to help raise the temperature of air breathed in. Anti-inflammatory drugs and those which prevent bronchial constriction may also be helpful, according to the lung experts.

But above all athletes should refrain from endurance training and competition while suffering from respiratory infections.