| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1Allan McGavin Sport Medicine Centre, Faculty of Medicine; 2School of Human Kinetics; and 3Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada
Submitted 19 May 2007 ; accepted in final form 15 October 2007
The purpose of this study was to compare chemoresponses following two different intermittent hypoxia (IH) protocols in humans. Ten men underwent two 7-day courses of poikilocapnic IH. The long-duration IH (LDIH) protocol consisted of daily 60-min exposures to normobaric 12% O2. The short-duration IH (SDIH) protocol comprised twelve 5-min bouts of 12% O2, separated by 5-min bouts of room air, daily. Isocapnic hypoxic ventilatory response (HVR) was measured daily during the protocol and 1 and 7 days following. Hypercapnic ventilatory response (HCVR) and CO2 threshold and sensitivity (by the modified Read rebreathing technique) were measured on days 1, 8, and 14. Following 7 days of IH, the mean HVR was significantly increased from 0.47 ± 0.07 and 0.47 ± 0.08 to 0.70 ± 0.06 and 0.79 ± 0.06 l·min–1·%SaO2–1 (LDIH and SDIH, respectively), where %SaO2 is percent arterial oxygen saturation. The increase in HVR reached a plateau after the third day. One week post-IH, HVR values were unchanged from baseline. HCVR increased from 3.0 ± 0.4 to 4.0 ± 0.5 l·min–1·mmHg–1. In both the hyperoxic and hypoxic modified Read rebreathing tests, the slope of the CO2/ventilation plot was unchanged by either intervention, but the CO2/ventilation curve shifted to the left following IH. There were no correlations between the changes in response to hypoxia and hypercapnia. There were no significant differences between the two IH protocols for any measures, indicating that comparable changes in chemoreflex control occur with either protocol. These results also suggest that the two methods of measuring CO2 response are not completely concordant and that the changes in CO2 control do not correlate with the increase in the HVR.
hypoxic ventilatory response; hypercapnic ventilatory response
This article has been cited by other articles:
|
|
 |
|
  V. Pialoux, P. J. Hanly, G. E. Foster, J. V. Brugniaux, A. E. Beaudin, S. E. Hartmann, M. Pun, C. T. Duggan, and M. J. Poulin Effects of Exposure to Intermittent Hypoxia on Oxidative Stress and Acute Hypoxic Ventilatory Response in Humans Am. J. Respir. Crit. Care Med., November 15, 2009; 180(10): 1002 - 1009. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. S. Lee, M. S. Badr, and J. H. Mateika Progressive augmentation and ventilatory long-term facilitation are enhanced in sleep apnoea patients and are mitigated by antioxidant administration J. Physiol., November 15, 2009; 587(22): 5451 - 5467. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. H. Mateika and G. Narwani Intermittent hypoxia and respiratory plasticity in humans and other animals: does exposure to intermittent hypoxia promote or mitigate sleep apnoea? Exp Physiol, March 1, 2009; 94(3): 279 - 296. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. N. Ainslie, M. Hamlin, J. Hellemans, P. Rasmussen, and S. Ogoh Cerebral hypoperfusion during hypoxic exercise following two different hypoxic exposures: independence from changes in dynamic autoregulation and reactivity Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2008; 295(5): R1613 - R1622. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Wadhwa, C. Gradinaru, G. J. Gates, M. S. Badr, and J. H. Mateika Impact of intermittent hypoxia on long-term facilitation of minute ventilation and heart rate variability in men and women: do sex differences exist? J Appl Physiol, June 1, 2008; 104(6): 1625 - 1633. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
