Summary
Meta-analysis confirms that acute high-altitude exposure reduces parasympathetic HRV indices and shifts autonomic balance toward sympathetic dominance, though individual responses vary significantly.
Methods
Systematic review and meta-analysis of altitude-HRV studies
Key Findings
- RMSSD and pNN50 decrease at altitude (parasympathetic drop)
- Shift from vagal to sympathetic predominance
- Individual variability in responses significant
- Acclimatization duration affects adaptation
Limitations
Heterogeneity in altitude levels, exposure durations, study designs
What This Means for You
Expect lower HRV when traveling to altitude. This is a normal physiological response to hypoxia. Give yourself time to acclimatize, and don't interpret altitude-suppressed HRV as overtraining or illness. Your HRV should normalize as you adapt.
Source
Read the original paper in Frontiers in Physiology ↗
Added to HRV Zone: 2026-01-23