Rapidity of responding to a hypoxic challenge during exercise

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Rebecca Battista Ph.D, Associate Professor (Creator)
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/

Abstract: The ability to modify power output (PO) in response to a changing stimulus during exercise is crucial for optimizing performance involving an integration systeminvolving a performance template and feedback from peripheral receptors. The rapidity with which PO is modified has not been established, but would be of interest relativeto understanding how PO is regulated. The objective is to determine the rapidity of changes in PO in response to a hypoxic challenge, and if change in PO is linked to changesin arterial O2 saturation (SaO2). Well-trained cyclists performed randomly ordered 5-km time trials. Subjects began the trials breathing room air and switched to hypoxic(HYPOXIC, FIO2 = 0.15) or room (CONTROL, FIO2 = 0.21) air at 2 km, then to room air at 4 km. The time delay to begin decreasing SaO2 and PO and to recover SaO2 andPO on to room air was compared, along with the half time (t1/2) during the HYPOXIC trial. Mean SaO2 and between 2 and 4 km were significantly diVerent betweenCONTROL and HYPOXIC (94 + 2 vs. 83 + 2% and 285 + 16 vs. 245 + 19 W, respectively). There was no difference between the time delay for SaO2 (31.5 + 12.8 s)and in PO (25.8 § 14.4 s) or the recovery of SaO2 (29.0 + 7.7 s) and PO (21.5 + 12.4 s). The half time for decreases in SaO2 (56.6 + 14.4 s) and in PO (62.7 + 20.8 s) was not significantly different. Modifications of PO due to the abrupt administration of hypoxic air are related to thedevelopment of arterial hypoxemia, and begin within»30 s.

Additional Information

Blair D. Johnson · Trent Joseph · Glenn Wright ·Rebecca A. Battista · Christopher Dodge ·Alecia Balweg · Jos J. de Koning · Carl Foster (2009) "Rapidity of responding to a hypoxic challenge during exercise" European Journal of Applied Physiology #106: 493-499 Version of Record Available @ (DOI 10.1007/s00421-009-1036-3)
Language: English
Date: 2009
Cycling, Altitude, Pacing, Hypoxia

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