Effect of acute normobaric hypoxia on the ventilatory threshold

Eur J Appl Physiol. 2014 Aug;114(8):1555-62. doi: 10.1007/s00421-014-2882-1. Epub 2014 Apr 23.

Abstract

Purpose: This study investigated the response of the ventilatory threshold (VT) to acute normobaric hypoxia and compared the agreement between software-based algorithms which use automatic detection to identify the VT. Results were used to examine whether the VT can be used as a physiological parameter to prescribe and monitor exercise intensity in hypoxic exercise training programs.

Methods: Fourteen untrained individuals (7 women, 7 men; age 22 ± 2 years, [Formula: see text]O2peak 46 ± 7 mL kg(-1) min(-1)) completed five identical graded exercise tests (randomized order) on a cycle ergometer to measure VT at sea-level (SL) and in response to four normobaric hypoxic conditions (FIO2: 0.185, 0.165, 0.142, 0.125) equivalent to 1,000, 2,000, 3,000 and 4,000 m. Data were analyzed using a one-way analysis of variance (ANOVA) with repeated measures.

Results: The VT was similar across all conditions (SL = 1.98 ± 0.46, 1,000 m = 2.03 ± 0.61, 2,000 m = 2.27 ± 0.62, 3,000 m = 1.84 ± 0.50, 4,000 m = 2.29 ± 0.58 L min(-1)) for all algorithms used despite a reduction in arterial oxygen saturation at 3,000 (P ≤ 0.01) and 4,000 m (P ≤ 0.01) compared with SL values.

Conclusion: The VT appears to be a suitable physiological parameter for exercise prescription in normobaric hypoxia up to an altitude of 4,000 m.

Publication types

  • Evaluation Study

MeSH terms

  • Altitude*
  • Exercise*
  • Female
  • Humans
  • Hypoxia / physiopathology*
  • Male
  • Oxygen Consumption
  • Pulmonary Ventilation*
  • Young Adult