Same Performance Changes after Live High-Train Low in Normobaric vs. Hypobaric Hypoxia.

Jonas J. Saugy,Roberto Cejuela,Laurent Schmitt,Grégoire P. Millet,Guillaume Constantin,Raphael Faiss,Anna Hauser,Jon P. Wehrlin,Neil Robinson,Jérémie Rosset

doi:10.3389/fphys.2016.00138

Abstract

Purpose: We investigated the changes in physiological and performance parameters after a Live High-Train Low (LHTL) altitude camp in normobaric (NH) or hypobaric hypoxia (HH) to reproduce the actual training practices of endurance athletes using a crossover-designed study.Methods: Well-trained triathletes (n = 16) were split into two groups and completed two 18-day LTHL camps during which they trained at 1100–1200 m and lived at 2250 m (PiO2 = 111.9 ± 0.6 vs. 111.6 ± 0.6 mmHg) under NH (hypoxic chamber; FiO2 18.05 ± 0.03%) or HH (real altitude; barometric pressure 580.2 ± 2.9 mmHg) conditions. The subjects completed the NH and HH camps with a 1-year washout period. Measurements and protocol were identical for both phases of the crossover study. Oxygen saturation (SpO2) was constantly recorded nightly. PiO2 and training loads were matched daily. Blood samples and VO2max were measured before (Pre-) and 1 day after (Post-1) LHTL. A 3-km running-test was performed near sea level before and 1, 7, and 21 days after training camps.Results: Total hypoxic exposure was lower for NH than for HH during LHTL (230 vs. 310 h; P < 0.001). Nocturnal SpO2 was higher in NH than in HH (92.4 ± 1.2 vs. 91.3 ± 1.0%, P < 0.001). VO2max increased to the same extent for NH and HH (4.9 ± 5.6 vs. 3.2 ± 5.1%). No difference was found in hematological parameters. The 3-km run time was significantly faster in both conditions 21 days after LHTL (4.5 ± 5.0 vs. 6.2 ± 6.4% for NH and HH), and no difference between conditions was found at any time.Conclusion: Increases in VO2max and performance enhancement were similar between NH and HH conditions.

Highlights

Endurance athletes commonly use altitude training camps with several hypoxic methods to achieve maximal sea-level performance enhancement (Millet et al, 2010)
Increases in VO2max and performance enhancement were similar between NH and hypobaric hypoxia (HH) conditions
SpO2 values were similar between two groups during the control nights, but values were higher in NH than in HH during the entire camp (D1–D18; 92.4 ± 1.2 vs. 91.3 ± 1.0%, for NH and HH, P < 0.001)

Summary

Introduction

Endurance athletes commonly use altitude training camps with several hypoxic methods to achieve maximal sea-level performance enhancement (Millet et al, 2010). More than 15 years of research have revealed that LHTL is an effective training method to enhance sea-level performance in endurance athletes, and it provided 1–3% additional benefit compared with similar normoxic training, not confirmed by all studies (Siebenmann et al, 2012) These altitude-training camps are conducted under “real” [i.e., hypobaric hypoxia, HH (Stray-Gundersen and Levine, 2008; Chapman et al, 2014; Saugy et al, 2014)] or simulated altitudes [i.e., normobaric hypoxia, NH (Dehnert et al, 2002; Clark et al, 2009; Garvican et al, 2011; Schmitt and Millet, 2012)]. Pre-acclimatization effectiveness (Fulco et al, 2013) and acute mountain sickness (AMS) scoring (Dipasquale et al, 2015) are logically higher in HH

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