# Real-time thermoregulatory and cardiovascular monitoring of non-acclimatised mountaineers in extreme cold: a 10-day field expedition study

## TL;DR

This study monitored the body temperature and heart rate of mountaineers in extreme cold to improve safety through real-time data tracking.

## Contribution

The study introduces a wearable system for real-time physiological monitoring in extreme cold environments.

## Key findings

- Cross-country skiing increased core temperature and heart rate more than snowshoe walking.
- Quinzhee camping provided better insulation than tent camping, as shown by higher core temperatures.
- Real-time monitoring enabled actionable alerts for safety during cold expeditions.

## Abstract

The primary aim of this study was to characterise the thermoregulatory and cardiovascular responses of non-acclimatised mountaineers during different exercise modalities and camping conditions in extreme cold. A secondary aim was to assess the feasibility of real-time transmission of physiological data to enhance safety during cold expeditions.

This study assessed thermoregulatory and cardiovascular responses of 18 non-acclimatised mountaineers from the United Arab Emirates during a 10-day winter expedition in Skeikampen, Norway. Participants performed daily cross-country skiing or snowshoe walking (∼5–6 h/day) and experienced two camping conditions (quinzhee and tent). Core temperature (Tc) was measured via ingestible telemetric pills, and heart rate (HR) via chest straps. Data were transmitted in real-time using a wearable ecosystem comprising Bluetooth gateways and eSIM-enabled smartwatches.

Cross-country skiing elicited significantly higher mean Tc (+0.20 °C, p < 0.01) and HR (+12.8 bpm, p < 0.01) than snowshoe walking. Peak Tc during quinzhee camping was significantly higher than during tent camping (+0.55 °C, p = 0.03), suggesting superior insulation. No cases of hypothermia were recorded. Real-time data transmission enabled continuous remote monitoring, with actionable alerts triggered when Tc dropped below safety thresholds.

This study demonstrates the feasibility of real-time physiological monitoring in extreme cold, offering practical insight into activity-specific thermoregulatory strain. The findings underscore the importance of shelter design, physical activity selection, and wearable monitoring to enhance safety and decision-making in cold environments.