Muscle Oxygenation During Repeated Double-Poling Sprint Exercise in Normobaric Hypoxia and Normoxia

We compared upper limb muscle oxygenation responses during repeated double-poling sprint exercise in normobaric hypoxia and normoxia. Eight male kayakers completed a repeated double-poling sprint exercise (3 x 3 x 20-s maximal sprints, 40-s passive recovery, 5-min rest) in either hypoxia (HYP, FiO(2) = 14.5%) or normoxia (NOR, FiO(2) = 20.9%). Power output, muscle oxygenation of triceps brachii muscle (using near infrared spectroscopy), arterial oxygen saturation, and cardiorespiratory variables were monitored. Mean power output tended to be lower (-5.2%; P = 0.06) in HYP compared with NOR, while arterial oxygen saturation (82.9 +/- 0.9% vs. 90.5 +/- 0.8%) and systemic oxygen uptake (1936 +/- 140 vs. 2408 +/- 83 mL.min(-1)) values were lower (P < 0.05). Exercise-induced increases in deoxygenated hemoglobin (241.7 +/- 46.9% vs. 175.8 +/- 27.2%) and total hemoglobin (138.0 +/- 18.1% vs. 112.1 +/- 6.7%) were greater in HYP in reference to NOR (P < 0.05). Despite moderate hypoxia exacerbating exercise-induced elevation in blood perfusion of active upper limb musculature, power output during repeated double-poling exercise only tended to be lower.