Copyright © 2007 Undersea and Hyperbaric Medical Society, Inc 407 UHM 2007 Vol.34, No.6 – Apnea in underwater hockey players Physiological responses to repeated apneas in underwater hockey players and controls. Submitted 5/3/07; Accepted 6/20/07 F. LEMAÎTRE 1,2 , D. POLIN 3 , F. JOULIA 4,2 , A. BOUTRY 3 , D. LE PESSOT 3 , D. CHOLLET 1 , C.TOURNY-CHOLLET 1 1 Centre d’Etudes des Transformations des Activités Physiques et Sportives, Equipe d’Accueil UPRES N°3832. Faculté des Sciences du Sport et de l’Education Physique de Rouen, Université de Rouen, France, 2 Association pour la Promotion de la Recherche sur l’Apnée et les Activités Subaquatiques (A.P.R.A.A.S.), 3 Service de Physiologie Respiratoire et Sportive, Hôpital de Bois Guillaume, 76031 Rouen, 4 Laboratoire d’Ergonomie Sportive et Performance Motrice ESP, UPRES EA n°3162, UFRSTAPS de Toulon, Université de Toulon et du Var, BP 132, 83957 La Garde, France. Lemaitre F, Polin D, Foulia F, Boutry A, LePessot D, Chollet D, Tourny-Chollet C. Physiological responses to repeated apneas in underwater hockey players and controls. Undersea Hyperb Med 2007; 34(6):407- 414. The aim of this study was to investigate the effects of short repeated apneas on breathing pattern and circulatory response in trained (underwater hockey players: UHP) and untrained (controls: CTL) subjects. The subjects performed five apneas (A1-A5) while cycling with the face immersed in thermoneutral water. Respiratory parameters were recorded 1 minute before and after each apnea and venous blood samples were collected before each apnea and at 0, 2, 5 and 10 minutes after the last apnea. Arterial saturation (SaO 2 ) and heart rate were continuously recorded during the experiment. Before the repeated apneas, UHP had lower ventilation, higher P ET CO 2 (p<0.05) and lower P ET O 2 than CTL (p<0.001). After the apneas, the P ET O 2 values were always lower in UHP (p<0.001) than CTL but with no difference for averaged P ET CO 2 (p=0.32). The apnea response, i.e., bradycardia and increased mean arterial blood pressure, was observed and it remained unchanged throughout the series in the two groups. The SaO 2 decreased in both groups during each apnea but the post-exercise SaO 2 values were higher in UHP after A2 to A5 than in CTL (p<0.01). The post- apnea lactate concentrations were lower in UHP than in CTL. These results indicate that more pronounced bradycardia could lead to less oxygen desaturation during repeated apneas in UHP. The UHP show a specific hypoventilatory pattern after repeated apneas, as well as a more pronounced cardiovascular response than CTL. They indeed showed no detraining of the diving response. INTRODUCTION The diving response is characterized by bradycardia, peripheral vasoconstriction, decreased cardiac output, and a gradual elevation in arterial pressure with consequent lactate accumulation in unperfused muscle, and elite apnea divers display a more pronounced response than novices (1). Apnea diving is a new sport that is usually characterized by prolonged apneas at rest or at low exercise intensity. However, in several sports, such as judo, track and field, basketball and soccer, athletes are required to perform high intensity intermittent exercise. Intermittent training decreases the recovery period after submaximal exercise (2) and this effect has been explained by a smaller increase in lactate concentration, an improvement in the quantity of oxygen available to active muscles, and better oxygen extraction (3). Underwater hockey players http://archive.rubicon-foundation.org