Cycling Time Trial Is More Altered in Hypobaric than Normobaric Hypoxia.
Med Sci Sports Exerc
; 48(4): 680-8, 2016 Apr.
Article
em En
| MEDLINE
| ID: mdl-26559447
ABSTRACT
PURPOSE:
Slight physiological differences between acute exposure in normobaric hypoxia (NH) and hypobaric hypoxia (HH) have been reported. Taken together, these differences suggest different physiological responses to hypoxic exposure to a simulated altitude (NH) versus a terrestrial altitude (HH). For this purpose, in the present study, we aimed to directly compare the time-trial performance after acute hypoxia exposure (26 h, 3450 min) by the same subjects under three different conditions NH, HH, and normobaric normoxia (NN). Based on all of the preceding studies examining the differences among these hypoxic conditions, we hypothesized greater performance impairment in HH than in NH.METHODS:
The experimental design consisted of three sessions NN (Sion FiO2, 20.93), NH (Sion, hypoxic room FiO2, 13.6%; barometric pressure, 716 mm Hg), and HH (Jungfraujoch FiO2, 20.93; barometric pressure, 481 mm Hg). The performance was evaluated at the end of each session with a cycle time trial of 250 kJ.RESULTS:
The mean time trial duration in NN was significantly shorter than under the two hypoxic conditions (P < 0.001). In addition, the mean duration in NH was significantly shorter than that in HH (P < 0.01). The mean pulse oxygen saturation during the time trial was significantly lower for HH than for NH (P < 0.05), and it was significantly higher in NN than for the two other sessions (P < 0.001).CONCLUSION:
As previously suggested, HH seems to be a more stressful stimulus, and NH and HH should not be used interchangeability when endurance performance is the main objective. The principal factor in this performance difference between hypoxic conditions seemed to be the lower peripheral oxygen saturation in HH at rest, as well as during exercise.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Ciclismo
/
Desempenho Atlético
/
Altitude
/
Hipóxia
Tipo de estudo:
Clinical_trials
Limite:
Adult
/
Humans
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Male
Idioma:
En
Revista:
Med Sci Sports Exerc
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
França