London, Dec 9 (IANS): If you show symptoms of respiratory disorders such as cough or sore throat after a session of vigorous exercise, increasing your vitamin C intake could offer relief, says a study.

A meta-analysis of three studies found that vitamin C significantly reduced post-exercise airway (the tubes that carry air into and out of the lungs) obstruction in participants who suffered from exercise-induced bronchoconstriction, the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle.

"It seems reasonable for physically active people to test whether vitamin C is beneficial on an individual basis, if they have documented exercise-induced bronchoconstriction or suffer from respiratory symptoms such as cough or sore throat after taking vigorous exercise," said Harri Hemila from the University of Helsinki in Finland.

The researchers found that an intake of vitamin C led to a reduction in post-exercise large-airway obstruction and small-airway obstruction.

Hemila carried out an analysis of a study which had 12 participants. The participants had asthma, were on average 26 years, and suffered from exercise-induced bronchoconstriction.

Five other studies examined subjects who were under short-term, heavy physical stress and a meta-analysis revealed that vitamin C halved the incidence of respiratory disorder symptoms.

Another trial reported that vitamin C halved the duration of the respiratory disorder symptoms in male adolescent competitive swimmers.

The study appeared in the journal Allergy, Asthma & Clinical Immunology.