2011, Volume 3, Issue 1

The Impact of 32 Days’ Exposure to Hypobaric Hypoxia on Physiological Cost of Sub-Maximal Work Performed at the Sea Level



Sylwester Kujach1, Tomasz Grzywacz2, Ewa Ziemann3, Robert Szymczak4, Marcin Łuszczyk5, Radosław Laskowski2

1Department of Physiology, Jedrzej Sniadecki Academy of Physical Education and Sport in Gdansk
21. Department of Physiology, 1. Jedrzej Sniadecki Academy of Physical Education and Sport in Gdansk; 2. Kazimierz Górski Higher School of Sports
3Department of Physiotherapy, Warsaw School of Social Sciences and Humanities
4Clinical Department of Emergency Medicine, Medical University of Gdansk
5Jedrzej Sniadecki Academy of Physical Education and Sport in Gdansk


Author for correspondence: Radosław Laskowski; 1. Department of Physiology, 1. Jedrzej Sniadecki Academy of Physical Education and Sport in Gdansk; 2. Kazimierz Górski Higher School of Sports; email: lasradek@awf.gda.pl


Full text

Abstract

Background: Many papers showed that long-lasting exposure to hypobaric hypoxia changed the metabolic cost of work and substrate contribution, elevating exercise energy expenditure and carbohydrates utilization. Only few of them have shown how long this adaptive changes are maintained. The aim of the study was to assess the impact of prolonged sojourn at high altitude on the physiological cost of sub-maximal work performed at the sea level. 
Materials and methods: Eight members of two high altitude expeditions (Lenin Peak 7,134 m a.s.l. and Somoni Peak 7,495 m a.s.l.), 7 males and 1 female, mean age 26 (±4.1) years, volunteered for this study. Aerobic performance was measured by a direct method (breath-by-breath) using an expiratory gas analyser (Oxycon Pro, Jaeger) with an incremental exercise test till exhaustion. The sea level examinations were performed 7 days before the expedition (BEx) and 7 days after (AEx) the last day at over 2,500 m a.s.l. Participants spent 32 (±3) days over 2,500 m a.s.l. at the mean altitude of 4,712 m a.s.l. (±499 m).
Results: Prolonged sojourn at high altitude has changed the ventilatory parameters of submaximal work measured at the sea level. The sojourn resulted in an increase in the ventilatory volume (tidal volume, minute ventilation and breath frequency) during the sub-maximal work performed with the same workload. However, the respiratory exchange ratio remained at a high level compared to the baseline.
Conclusions: We suggest that the adaptive changes introduced during the sojourn remain at the sea level and cause increased carbohydrate metabolism.


Key words: hypobaric hypoxia, high altitude, metabolic cost