Submitted on November 21, 2006
Accepted on November 19, 2007
The Effect of Intermittent Hypobaric Hypoxic Exposure and Sea Level Training on Submaximal Economy in Well Trained Swimmers and Runners
Martin J. Truijens1, Ferran A. Rodriguez2, Nathan E. Townsend3, James Stray-Gundersen4, Christopher J. Gore5, and Benjamin D. Levine6*
1 Faculty of Human Movement Sciences, Vrije Universiteit, Netherlands
2 Institut Nacional d'Educacio Fisica de Catalunya, Universitat de Barcelona, Barcelona, Spain
3 New South Wales Institute of Sport, Sydney, Australia
4 Institute for Exercise and Environmental Medicine, Prebyterian Hospital, University of Texas at Southwester/IEEM, Dallas, Texas, United States
5 Exercise Physiology Laboratory, School of Education, Flinders University, Adelaide, Australia
6 Institute for Exercise and Environmental Medicine, Presbyterian Hospital, University of Texas at Southwestern/IEEM, Dallas, Texas, United States
* To whom correspondence should be addressed. E-mail: benjaminlevine{at}texashealth.org.
To evaluate the effect of intermittent hypobaric hypoxia combined with sea-level training on exercise economy, 23 well-trained athletes (13 swimmers, 10 runners) were assigned to either hypobaric hypoxia (simulated altitude of 4000-5500m) or normobaric normoxia (0-500m) in a randomized, double-blind design. Both groups rested in a hypobaric chamber 3 h/day, 5 days/wk for 4 weeks. Submaximal economy was measured twice PRE and POST the treatment period using sport specific protocols. Economy was estimated both from the relationship between oxygen uptake (VO2) and speed, and from the absolute VO2 at each speed using sport specific protocols. VO2 was measured during the last 60s of each (3-4 minute) stage using Douglas bags. Ventilation (VE), heart rate (HR), and capillary lactate ([La-]) were measured during each stage. Velocity at VO2max (vVO2max) was used as a functional indicator of changes in economy. The average VO2 for a given speed of the PRE values was used for POST test comparison using a two-way, repeated measures ANOVA. Typical error of measurement of VO2 was 4.7% {95% confidence limits 3.6 to 7.1}, 3.6% {2.8 to 5.4} & 4.2% {3.2 to 6.9} for speeds 1, 2 & 3 respectively. There was no change in economy within or between groups (ANOVA interaction p=0.28, p=0.23 & p=0.93 for speeds 1, 2 & 3). No differences in submaximal HR, [La-], VE or vVO2max were found between groups. It is concluded that four weeks of intermittent hypobaric hypoxia did not improve submaximal economy in this group of well-trained athletes.
