It is already known that women experience a greater shortness of breath when exercising compared to men, however scientists have finally discovered why.

According to a team from McGill University in Canada, women experience a greater shortness of breath when exercising compared to men of a similar age irrespective of whether they are young and healthy, older and healthy or if they have chronic heart and lung diseases.

For the purpose of this study, the scientists looked at 50 healthy men and women aged between 20 and 40. None of the participants smoked and all completed an exercise test on a stationary bike.

During this test, the participants' heart, metabolic and breathing responses were monitored using specialised computer equipment.

The study found that the reason why women find it harder to breathe during exercise is because of greater electrical activation of their breathing muscles.

"Our study uniquely showed that sex differences in activity-related breathlessness could be explained by the awareness of greater electrical activation of the respiratory muscles - specifically the diaphragm - needed to achieve any given ventilation during exercise in healthy young women compared to men.

"Our findings indicated that greater electrical activation of the respiratory muscles during exercise in women is needed to compensate for their biologically smaller lungs, airways and breathing muscles," explained lead scientist, Dr Dennis Jensen.

The team said it would like to see this research extended to other groups, such as obese men and women.

Details of these findings are published in the journal, Experimental Physiology.