Do you know if the subjects were (fully) acclimated to warm, humid conditions? There is significant adaptation possible (e.g. https://onlinelibrary.wiley.com/doi/full/10.1111/sms.12408).
Written by Rex Kerr
One who rejoices when everything is made as simple as possible, but no simpler. Sayer of things that may be wrong, but not so bad that they're not even wrong.