In a new study, researchers from McGill University, Canada, have identified one of the reasons why men always outshine women in the athletics department.

Researchers found that women have 'greater electrical activation' of their respiratory muscles, making it difficult for them to breathe than men during exercise.

Previous researchers have already established the fact that women experience greater shortness of breath during physical activity including stair climbing and long-distance running than men of similar age. This is the first study to explain the relationship between electrics in the chest muscles and women's exhaustion.

"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," Dr Dennis Jensen, who led the study at the University, said in a press release.

"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."

Researchers said that this finding can help medical practitioners to devise new treatments for problems relating to breathlessness and improve exercise capacity in the elderly and patients with chronic heart and lung disease.

"Fifty healthy, non-smoking men and women aged 20 to 40 years completed a maximum exercise test on a stationary bicycle. During exercise, we monitored the participants cardiovascular, metabolic and ventilatory responses to exercise using computerised equipment."

"At regular intervals during exercise, participants rated the intensity of their breathlessness using a 10-point scale. Using a multipair electrode catheter placed in the participants' oesophagus, we also recorded the electromyogram of the diaphragm - an index of the drive to breathe that presumably originates in the central nervous system - throughout exercise. These measurements were then analysed and compared between men and women."

The finding has been published in the journal Experimental Physiology.