Exercise-induced asthma, or bronchoconstriction, causes shortness of breath, wheezing and cough. These symptoms are caused by the decline of more than 10% in forced expiratory volume in one second (FEV1), caused by exercise, in patients with the condition.
Studies have shown that nearly one in ten people suffer from exercise-induced bronchoconstriction. It has also been discovered that close to half of all competitive winter-sports athletes suffer from its symptoms.
A new research review and meta-analysis has provided a possible treatment for preventing these symptoms, without the use of drugs. Its findings show that vitamin C may have the ability to reduce the risk of asthma by easing physical exertion from exercise.
Researchers in Switzerland reviewed three randomized, placebo-controlled trials that had utilized vitamin C for asthma patients. Participants had been tested with an exercise challenge, followed by measurement of FEV1. The study analyzed the effect that vitamin C had on the patients compared to the control groups. The findings of all three studies demonstrated that vitamin C resulted in a reduced FEV1 decline by over 50% in patients after exercise.
Head researcher, Dr. Henri Hemilia, said that patients with respiratory problems associated with exercise, such as cough or wheezing, should consider trying vitamin C and testing if it helps.
Other research has shown that vitamin C can help people under heavy physical stress, such as marathon runners, avoid catching a cold. However, that study revealed that vitamin C intake did not help the general population prevent colds.
Former research has suggested that vitamin D is another possibility for relieving asthma symptoms.
Hemilia H. Vitamin C may alleviate exercise-induced bronchoconstriction: a meta-analysis. BMJ OPen 2013; 3: e002416. doi:10.1136/bmjopen-2012-002416.
Hemilia H, Chalker E. Vitamin C for preventing and treating the common cold. The Cochrane Library 2013 (online); doi: 10.1002/14651858.CD000980.pub4.
Nordqvist Joseph. Vitamin C reduces exercise-induced bronchoconstriction (asthma) symptoms. Medical News Today, 17 Jun 2013. www.medicalnewstoday.com.