People who suffer from exercise-induced asthma have been encouraged not to give up on sport after it emerged that 25% of Team GB suffer from the respiratory condition.
A quarter of Britain's hopefuls including Tour de France champion Bradley Wiggins, swimmer Rebecca Adlington and marathon runner Paula Radcliffe all have asthma, according to charity Asthma UK.
About three-quarters of people with asthma say that exercise is a trigger for their condition. But the majority of people with exercise-induced asthma can take part in any sport they choose with proper training and medicine, the charity said.
Cyclist Wiggins told the charity: "It's only a hindrance if you make it one - it does sound quite bad if you are diagnosed with asthma and your natural instinct is to think that's it. But there is better medicine available now and I am an Olympic champion - the evidence is out there that you can succeed."
Defending Olympic rowing champions Pete Reed and Tom James both suffer from the condition as do swimmer Jo Jackson and footballer Craig Bellamy.
The charity said that people with asthma should participate in exercise as it improves lung function and can help with the management of symptoms.
Asthma UK spokeswoman Cher Piddock said: "There are some incredibly talented sportspeople with asthma but not everyone with the condition is able to compete at Olympic level like Bradley Wiggins or Rebecca Adlington. There are still around 250,000 people in the UK whose asthma is so severe that many of them are unable to walk to the shops or go to work.
"With the right medicines and support the majority of people with asthma should be able to take part in some sort of exercise, whether that's being able to reach the top of the stairs, the top of a mountain or the top of a podium.
"We'd encourage anyone with asthma who is struggling with their symptoms to speak to their GP or asthma nurse to ensure their asthma is as controlled as it can be."
Endurance sports are most likely to cause problems for people with exercise-induced asthma, including long-distance running, cross-country skiing and cycling. Symptoms of exercise-induced asthma include coughing, wheezing, chest-tightness and difficulty in breathing.