Is Continuous Monitoring of Skin Surface Temperature a Reliable Proxy to Assess the Thermoregulatory Response in Endurance Horses During Field Exercise?
Authors: Verdegaal Elisabeth-Lidwien J M M, Howarth Gordon S, McWhorter Todd J, Delesalle Catherine J G
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Hyperthermia significantly impacts both performance and welfare in endurance horses, yet field-based assessment of thermoregulatory stress has remained challenging because surface skin temperature monitoring has not been systematically compared with core temperature during actual competition. Verdegaal and colleagues evaluated 13 endurance horses across four field rides (40–80 km total), using infrared thermography to continuously record skin temperature every 15 seconds alongside core temperature data from gastrointestinal telemetry pills, with ambient temperatures ranging from 6.7–18.4°C. Despite widespread use in practice, skin temperature proved an unreliable indicator of core thermoregulatory response: no meaningful relationship existed between skin and core temperature profiles during exercise or recovery, maximum skin temperature was reached in just 67 minutes at 30.3°C compared to 139 minutes and 39°C for core temperature, and skin temperature changes failed to differentiate meaningfully between work and rest periods. Weather conditions, evaporative cooling patterns, and regional blood flow changes can all alter skin surface readings independently of true core temperature, whilst the horses demonstrated substantial individual variation in both thermal profiles. For practitioners relying on surface temperature monitoring to assess endurance horses during competition, these findings suggest that skin temperature alone is insufficient as a welfare indicator; multimodal assessment incorporating resting heart rate recovery, respiratory patterns, and clinical observation remains essential to accurately evaluate thermoregulatory strain.
Read the full abstract on PubMed
Practical Takeaways
- •Relying solely on surface skin temperature monitoring is insufficient for assessing heat stress or welfare during endurance rides; core temperature measurement provides more reliable data on thermoregulatory burden
- •Individual horses show very different patterns of heat response, so one-size-fits-all cooling or pacing strategies may not be optimal—get to know your horse's normal temperature profile
- •Environmental factors (wind, humidity, shade) significantly influence skin temperature readings independent of actual metabolic heat load, so field conditions must be considered when interpreting temperature data
Key Findings
- •Surface skin temperature (Tsk) showed no correlation with core temperature (Tc) during exercise and recovery in endurance horses
- •Time to maximum Tsk (67 min) was significantly faster than Tc (139 min), with lower maximum Tsk (30.3°C) than Tc (39°C)
- •Multiple environmental and physiological factors modulate Tsk independently of Tc, making it an unreliable sole indicator of thermoregulatory stress
- •Significant inter-individual variability in temperature profiles emphasizes need for individualized monitoring approaches