Seasonal variations of cough reflex sensitivity in elite athletes training in cold air environment

Fifty-three elite winter athletes and 33 sedentary subjects completed a respiratory questionnaire and a capsaicin provocation test during the summer, fall, and winter. Allergy skin prick tests, spirometry, eucapnic voluntary hyperpnea test (EVH), methacholine inhalation test (MIT), and induced sputum analysis were also performed.In athletes, the prevalence of cough immediately after exercise was high, particularly during winter. Athletes often showed a late occurrence of cough between 2-8 h after exercise. The cough reflex sensitivity to capsaicin was unchanged through the seasons in both athletes and non-athlete subjects. No significant correlations were found in groups between cough reflex sensitivity to capsaicin and the number of years in sport training, the number of hours of training per week, EVH response (% fall in FEV1), airway responsiveness to methacholine (PC20), airway inflammation or atopy.The prevalence of cough immediately and a few hours after exercise is high in athletes and more frequently reported during winter. However, cough does not seem to be associated with cough reflex hypersensitivity to capsaicin, bronchoconstriction, or airway inflammation in the majority of athletes.Cough is widely recognized as a key symptom in the diagnosis of asthma, being frequently related to an upper or lower respiratory tract infection or associated to post nasal drip syndrome and gastro-oesophageal reflux [1]. It may also be due to environmental exposures.In elite athletes, particularly those training in a cold-air environment, exercise-induced cough is a common complaint [2,3]. Usually, the inspired air is warmed up to body temperature through heat exchange in the upper airways, before entering into the lungs. However, this mechanism is compromised during exercise in cold weather because nose breathing switch to mouth breathing. Consequently, the air reaching trachea and bronchi can be as low as 20°C due to an insufficient heat exchange [4,5].The high frequency