Impaired interval exercise responses in elite female cyclists at moderate simulated altitude.
The effect of hypoxia on the response to interval exercise was determined in eight elite female cyclists during two interval sessions: a sustained 3 x 10-min endurance set (5-min recovery) and a repeat sprint session comprising three sets of 6 x 15-s sprints (work-to-relief ratios were 1:3, 1:2, and 1:1 for the 1st, 2nd, and 3rd sets, respectively, with 3 min between each set). During exercise, cyclists selected their maximum power output and breathed either atmospheric air (normoxia, 20.93% O(2)) or a hypoxic gas mix (hypoxia, 17.42% O(2)). Power output was lower in hypoxia vs. normoxia throughout the endurance set (244+/-18 vs. 226+/-17, 234+/-18 vs. 221+/-25, and 235+/-18 vs. 221+/-25 W for 1st, 2nd, and 3rd sets, respectively; P< 0.05) but was lower only in the latter stages of the second and third sets of the sprints (452+/-56 vs. 429+/-49 and 403+/-54 vs. 373+/- 43 W, respectively; P<0.05). Hypoxia lowered blood O(2) saturation during the endurance set (92.9+/-2.9 vs. 95.4+/-1.5%; P<0.05) but not during repeat sprints. We conclude that, when elite cyclists select their maximum exercise intensity, both sustained (10 min) and short-term (15 s) power are impaired during hypoxia, which simulated moderate ( approximately 2,100 m) altitude.
Brosnan
M J
MJ
Exercise Metabolism Group, Department of Human Biology and Movement Science, Royal Melbourne Institute of Technology University, Bundoora, Victoria 3183, Australia 2616.
Martin
D T
DT
Hahn
A G
AG
Gore
C J
CJ
Hawley
J A
JA
D000143:Acids / Q000097:blood; D000531:Altitude; D001639:Bicarbonates / Q000097:blood; D001642:Bicycling; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D000860:Hypoxia / Q000503:physiopathology*; D019344:Lactic Acid / Q000097:blood; D010092:Oximetry; D010100:Oxygen / Q000008:administration & dosage* / Q000097:blood; D010108:Oxyhemoglobins / Q000378:metabolism; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*; D012420:Running / Q000502:physiology
D000143:Acids; D001639:Bicarbonates; D010108:Oxyhemoglobins; D019344:Lactic Acid; D010100:Oxygen