title: Tissue oxygenation in men and women during repeated-sprint exercise.
abstract: OBJECTIVE
  To understand the role of O2 utilization in the sex differences of fatigue during intermittent activity, we compared the cerebral (prefrontal lobe) and muscle (vastus lateralis) oxygenation of men and women during repeated-sprint exercise (RSE).
  
  
  METHODS
  Ten men and 10 women matched for initial-sprint mechanical work performed ten, 10 s cycle sprints (with 30 s of rest) under normoxic (NM: 21% FIO2) and acute hypoxic (HY: 13% FIO2) conditions in a randomized single-blind and crossover design. Mechanical work was calculated and arterial O2 saturation (SpO2) was estimated via pulse oximetry during every sprint. Cerebral and muscle oxy- (O2Hb) and deoxy-hemoglobin (HHb) were monitored continuously by near-infrared spectroscopy.
  
  
  RESULTS
  Compared with NM, work decrement was accentuated (P = 0.01) in HY for both men (-16.4 ± 10.3%) and women (-16.8 ± 9.0%). This was associated with lower SpO2 and lower cerebral Δ[O2Hb] in both sexes (-13.6 ± 7.5%, P = .008, and -134.5 ± 73.8%, P = .003, respectively). These HY-induced changes were nearly identical in these men and women matched for initial-sprint work. Muscle Δ[HHb] increased 9-fold (P = .009) and 5-fold (P = .02) in men and women, respectively, and plateaued. This muscle deoxygenation was not exacerbated in HY.
  
  
  CONCLUSIONS
  Results indicate that men and women matched for initial-sprint work experience similar levels of fatigue and systemic, cerebral, and peripheral adjustments during RSE performed in NM and HY. These data suggest that cerebral deoxygenation imposes a limitation to repeated-sprint performance.
authors: Department of Human Kinetics, University of British Columbia Okanagan, Kelowna, BC, Canada.
authors: Kurt J
authors: KJ
authors: Smith
authors: François
authors: F
authors: Billaut
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D017397:Prefrontal Cortex / Q000378:metabolism*; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult
chemical_list: D010100:Oxygen