If you find it relaxing then do it to relax, but don’t over do it. Regarding what you heard on the podcast or read in the forum pertaining to saunas, that concerns heat adaption training.
Excessive heat is a stressor to the body but likely not enough to ruin your recovery week unless you’re spending an exorbitant amount of time in the sauna.
Heat adaptation will go away after only like a week or 2. So unless you have a hot race coming up, the added stresses you put on your system won’t be of much benefit.
I’ve always enjoyed using the sauna for half an hour after heavy rides or gym sessions. Definitely find it relaxing. Same before a race. (Seems like some of best power records are coming from relaxing in the sauna the day before + caffeine hit pre race)
Fairly regular sauna user here and have noticed a few things over time. I sauna in the evening and do TR rides early in the morning. I’ve noticed a marked RPE increase in all types of rides the morning after a sauna. Heart rate is elevated as well. While in the sauna I drink about 24 oz of water and still notice a drop in body weight. The next morning I’ll hop on the tanita scale and body water percentage is back within “normal” ranges given measurement tolerances.
Based on what I’ve experienced sauna’s provide the best benefit when kept short an endurance type ride is scheduled the next morning.