With my asthma, it doesn't even require heat to cause other issues. I am very attuned to my body and its responses to environmental stimuli as it relates to my condition. I have noticed that my body temperature begins to rise soon after starting to wear the mask even in an air conditioned office.
My employer is currently requiring temperature scans to enter the building and wearing of masks while on site. Thankfully, my role has been primarily WFH since mid-March because on the few occasions it has been necessary for me to go into the office, I have been miserable with the mask for even a short time. Yesterday was one such time I needed to go into the office briefly and I decided to perform an informal experiment. I asked the employee doing the temperature scan to write down my reading on entering the building and then to check me again as I exited. In just 20 minutes of non-exertion wearing a mask in a comfortable indoor environment, my scannable temperature rose 0.9 degrees. It takes an hour and a half mowing the lawn (self-propelled walk behind mower) in the hot sun to do the same.
Masks = bad news for me.