Alterations in autonomic cardiac modulation in response to normobaric hypoxia
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Giles_2016_Alterations_in_Auto ...
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Abstract
Purpose: The present study aimed to determine if autonomic cardiac modulation was influenced by acute exposure to normobaric hypoxia. Method: Ten healthy male lowland dwellers completed five block-randomised single-blinded, crossed-over acute exposures to a normobaric hypoxic environment, each separated by 24 hours’ recovery (20.3%, 17.4%, 14.5%, 12.0% and 9.8% FIO2). Supine recordings were made of arterial oxygen saturation and electrocardiogram (ECG). RR intervals from the ECG trace were analysed for time (SDNN, lnRMSSD), frequency (lnVLF, lnLF, lnHF, lnTP, LFnu, and HFnu), and nonlinear (DFA-α1 and SampEn) heart rate variability components. Results: A significant reduction in arterial SaO2 occurred with reduced FIO2, along with a rise in heart rate (Cohen’s d = 1.16, 95% Confidence Interval [2.64–6.46]), significant at 9.8% FIO2. A decrease in autonomic cardiac modulation was also found as shown by a statistically significant (at 9.8% FIO2) decrease in lnTP (d = 1.84 [1.74–1.94]), and SampEn (d = 0.98 [0.83–1.12]) and an increase in DFA-α1 (d = 0.72 [0.60–0.84]) from normoxia at 9.8% FIO2. Conclusion: The decrease in variability indicated a reduction in autonomic cardiac modulation. There appears to be a threshold ∼9.8% FIO2 (∼6000 m equiv.), below which significant alterations in autonomic control occur.Citation
Giles, D. et al (2016) 'Alterations in autonomic cardiac modulation in response to normobaric hypoxia', European Journal of Sport Science, 16 (8):1023Publisher
Taylor and FrancisJournal
European Journal of Sport ScienceDOI
10.1080/17461391.2016.1207708Additional Links
https://www.tandfonline.com/doi/full/10.1080/17461391.2016.1207708Type
ArticleLanguage
enISSN
1746-1391EISSN
1536-7290ae974a485f413a2113503eed53cd6c53
10.1080/17461391.2016.1207708
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Except where otherwise noted, this item's license is described as Archived with thanks to European Journal of Sport Science