Vitamin C reduces the respiratory symptoms associated with exercise. Physical activity increases the body’s oxidative stress, sometimes causing respiratory distress and exercise induced broncho-construction.
Several studies have revealed that consuming vitamin C curbs the increases in oxidative stress markers caused by exercise. In addition vitamin C is involved in the metabolism of histamine, prostaglandins, and cysteinyl leukotrienes, all of which appear to be mediators in the pathogenesis of exercise-induced bronchoconstriction.
Vitamin C has been found to halve the standard pulmonary function outcome (FEV1) in research participants experiencing exercise-induced bronchoconstriction. FEV1 measures the amount of large-airway obstruction. 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 symptoms. Another trial reported that vitamin C halved the duration of the respiratory symptoms in male adolescent competitive swimmers.
Vitamin C was found to reduce respiratory distress symptoms in a study carried out by the University of Helsinki in Finland. Twelve research participants suffered from exercise-induced bronchoconstriction. Vitamin C administration increased the post-exercise lung function in participants by between 50% and 150%.
Dr. Hemila the senior study author concluded that “given the safety and low cost of vitamin C, and the consistency of positive findings in the nine randomized trials on vitamin C against exercise-induced bronchoconstriction and respiratory symptoms, 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.”
The effect of vitamin C on bronchoconstriction and respiratory symptoms caused by exercise: a review and statistical analysis, Harri Hemilä, Allergy, Asthma & Clinical Immunology, doi:10.1186/1710-1492-10-58, published 27 November 2014.