Incremental strength test in normoxia and hypoxia conditions: effects on heart rate variability
It is apparent that exposure to high altitude is an environmental stressor that elicits a robust sympathoadrenal response that contributes to many of the critical adjustments and adaptations of body systems.
Background:
It is apparent that exposure to high altitude is an environmental stressor that elicits a robust sympathoadrenal response that contributes to many of the critical adjustments and adaptations of body systems.
Objectives:
To determine the impact of incremental strength test under hypoxia condition on heart rate variability.
Design
: A within-subject experimental design.
Participants
: High level Judokas competing at national and international levels (n=6). Main outcome measures: Temporal domain heart rate variability (SDNN, RMSSD, HRV Index) and Frequency domain heart rate variability (VLF, LF, HF frequency components and balance LF/HF) on shortterm (5min). All outcomes measures were assessed at two conditions: normoxia (NOR) (Granada) and at moderate hypoxia (HYP) (CAR, Sierra Nevada), before and after incremental strength test, consisted on an increasing loads (F-V curve) in the bench press. Results: In baseline conditions, there was not differences between two conditions in different parameters and a tendency to increase (P=0.06) in HF, HYP conditions respect NOR. After incremental strength test, we found both significative increase (P< 0.05) of LF domain and (P<0.02) balance LF/HF in HYP conditions respect normoxia conditions.
Conclusions:
The increase LF component, and LF/HF ratio suggests that a single exposure to hypoxic training increased the response of the autonomic nervous system mainly through increased sympathetic activity. In future studies we are focusing on the relationship between increased sympathetic activity and performance during strength tests.
