that is interesting. I have not experienced the chills or cold symptoms mentioned but I am cutting it back anyway. The only drawback is the cardio makes me feel good so its hard for me to make my self miss it.
I don't know it's impact on cortisol or if that's even been studied. Whether or not you'd feel as well after is also at question. However, if you just took that cardio time to go for a walk in the woods that is shown to be a mood boost. Could cut back to 1 min full go for the physical benefits and some nice nature strolls with minimal impact to see if that works for ya.