Autonomic Adaptations in Andean Trained Participants to a 4220-m Altitude Marathon

• Autores: Jérémy Cornolo, Catherine Privat, Fabiola León Velarde, Julien V. Brugniaux, Jose-Luis Macarlupu
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 37, Nº. 12, 2005, págs. 2148-2153
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Purpose: Both training and chronic hypoxia act on the autonomic nervous system. Because trained Andean high-altitude natives could perform a high-altitude marathon (4220 m above sea level) in 02:27:23 h, we hypothesized that living in chronic hypoxia does not limit the training-induced benefits on the autonomic modulation of the heart.

    Methods: Trained (N = 13) and sedentary (N = 11) Andean high-altitude natives performed an active orthostatic test. Eight of the trained subjects repeated the test 6-8 and 20-24 h after the end of a high-altitude marathon. Resting heart rate (HR) and the autonomic modulation of the heart were assessed by time domain and spectral analysis of HR variability (HRV): sympathetic (RR low frequency (LF)) and parasympathetic (RR high frequency (HF)) modulations, and sympathovagal balance (RR-LF:HF ratio).

    Results: Trained subjects exhibited a higher total power of HRV and a lower resting HR (+30%, P < 0.005) than sedentary subjects secondary to a higher and dominant parasympathetic modulation on sympathetic activity (RR-HF, RR-LF:HF ratio). At 6-8 h after the marathon, total power of HRV decreased (-69%), whereas resting HR increased from basal level (+22%), mainly because of a rise in sympathetic modulation (RR-LF, RR-LF:HF ratio). From 8 to 24 h of recovery, sympathetic modulation fell (RR-LF, RR-LF:HF ratio) and all HRV parameters were restored. Responses to the active standing position did not change between each recording session.

    Conclusion: Living in chronic hypoxia does not limit the training-induced benefits on the autonomic control of the cardiovascular system in Andean high-altitude natives. The sympathetic predominance on the heart observed 6-8 h after the high-altitude marathon disappeared after 1 d of recovery. Therefore, living at high altitude does not impair the autonomic response to training