How does increasing humidity affect physiological responses and performance? 🧐
In short...negatively.
Elevated Humidity Impairs Evaporative Heat Loss and Self-Paced Exercise Performance in the Heat
Study Details
This new study recruited 12 trained male cyclists to complete four 700‐kJ time trials at different humidities 🚴♂️
1️⃣ Low (32.9% relative humidity)
2️⃣ Moderate (50.5% relative humidity)
3️⃣ High (69.9% relative humidity)
4️⃣ Very High (88.4% relative humidity)
All trials were completed at ~33°C 🌡️
Performances were also self-paced (different to many previous studies) therefore reflecting real-world practice more accurately ✅
Key Findings
Sweating efficiency significantly decreased with elevated humidity 📉
👉 44% drop at High humidity
👉 68% drop at Very High humidity
(both vs low humidity sweat efficiency)
Power output was similar between Low and Moderate but was significantly lower in…
👉 Very High vs all other conditions
👉 High vs Low / Moderate humidities
Peak core temperature was significantly higher in Very High (39.49°C)…
…vs Low (38.97°C), Moderate (39.04°C) and High (39.12°C) 🥵
Mean skin temperature was also significantly elevated with increasing humidity 📈
Conclusion
Evaporative potential and sweat efficiency are significantly reduced in humid environments leading to impaired performance 🚨
🧊 Targeted preparation strategies (e.g. hydration, cooling, heat acclimation)
💦 Active during exercise strategies (e.g. sweat removal with towels, water dousing)
…must be employed to maintain performance in these conditions ✅