Un laryngospasme est une affection se caractérisant par la survenue d'accès de suffocation, qui commencent par une inspiration bruyante, suivis de mouvements respiratoires qui sont de plus en plus courts, et une phase pendant laquelle le patient ne respire pas
Vitamin D deficiency and exercise-induced laryngospasm in young competitive rowers
Enrico Heffler Applied Physiology, Nutrition, and Metabolism 03 March 2016.
Exercise induced dyspnea is common among adolescents and young adults, and often originates from exercise induced bronchoconstriction (EIB). Sometimes, dyspnea corresponds to exercise-induced laryngospasm, that is paradoxical decrease in supraglottic/glottic area (EILO). Vitamin D deficiency, that frequently occurs to our latitude, might favor laryngospasm by impairing calcium transport and slowing striate muscle relaxation.
AIM: To evaluate whether in young healthy athletes vitamin D status has an influence on bronchial and laryngeal response to exercise.
METHODS: EIB and EILO were investigated during winter in 37 healthy competitive rowers (24 males; age range 13-25 years), using the eucapnic voluntary hyperventilation test (EVH). EIB was diagnosed when Forced Expiratory Volume in the 1st second (FEV1 ) decreased by 10%, EILO when maximum mid-inspiratory flow (MIF50 ) decreased by 20%.
RESULTS: Most athletes (86.5%) had vitamin D deficiency (below 30 ng/ml), 29 mild-moderate (78.4%) and 3 severe (8.1%). EVH showed EIB in 10 subjects (27%) and EILO in 16 (43.2%), combined EIB and EILO in 6 (16.2%). Athletes with EILO had lower vitamin D (19.1 ng/ml vs 27.0 ng/ml, p<0.001) and higher parathyroid hormone (30.5 pg/ml, vs 19.2 pg/ml, p=0.006).
The degree of laryngoconstriction (MIF50 post-EVH as percent of pre-EVH test) was related directly with vitamin D levels (r= 0.51; p=0.001) and inversely with parathyroid hormone levels (r= -0.53; p=0.001).
CONCLUSIONS: Vitamin D deficiency is common during winter in young athletes living beyond 40° parallel and favors laryngospasm during exercise, probably by disturbing calcium homeostasis. This effect may negatively influence the athletic performance.