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The effect of hypoxia and exercise on heart rate variability, immune response, and orthostatic stress
Author(s) -
Koelwyn G. J.,
Wong L. E.,
Kennedy M. D.,
Eves N. D.
Publication year - 2013
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12003
Subject(s) - hypoxia (environmental) , medicine , heart rate , heart rate variability , orthostatic vital signs , orthostatic intolerance , cardiology , blood pressure , chemistry , oxygen , organic chemistry
Hypoxia with exercise is commonly used to enhance physiological adaptation in athletes, but may prolong recovery between training bouts. To investigate this, heart rate variability ( HRV ), systemic immune response, and response to an orthostatic challenge were measured following exercise in hypoxia and air. Eleven trained men performed a 10‐km cycling time trial breathing hypoxia (16.5 ± 0.5% O 2 ) or air. HRV and the heart rate response to an orthostatic challenge were measured for 3 days before and after each trial, while venous blood samples were collected pre‐, 0, 2, and 24 h post‐exercise. Hypoxia had no significant effect compared with air. Subgroup analysis of those who had a drop in oxyhemoglobin saturation ( SpO 2 ) > 10% between hypoxia and air compared with those who did not, demonstrated a significantly altered HRV response (△ HF nu: −2.1 ± 0.9 vs 8.6 ± 9.3, △ LF nu: 2.1 ± 1.0 vs −8.6 ± 9.4) at 24 h post‐exercise and increased circulating monocytes (1.3 ± 0.2 vs 0.8 ± 0.2 × 10 9 /L) immediately post‐hypoxic exercise. Exercise and hypoxia did not change HRV or the systemic immune response to exercise. However, those who had a greater desaturation during hypoxic exercise had an attenuate recovery 24 h post‐exercise and may be more susceptible to accumulating fatigue with subsequent training bouts.