Summary
Study found RMSSD correlates with cognitive performance during heat exposure, with a cubic relationship suggesting HRV can predict when heat stress begins impairing mental function.
Methods
Cognitive testing at 32°C, 36°C, 38°C, and 41°C with continuous ECG
Key Findings
- HRV time-domain indices vary with temperature and exposure time
- RMSSD most correlated with cognitive performance
- Cubic relationship between RMSSD and cognition
- HRV can predict heat-related cognitive impairment
Limitations
Laboratory conditions, healthy young adults
What This Means for You
In hot environments, your HRV drops—and so does your mental performance. If you're working or competing in heat, tracking HRV may help identify when you need to cool down before your thinking becomes impaired.
Source
Read the original paper in Indoor and Built Environment ↗
Added to HRV Zone: 2026-01-23