We have a jacuzzi and I run VERY HOT baths. I tend to tolerate them hotter than my husband (he is the cancer patient). Now that he's out of chemo he's enjoying the tub again, but the heat was too much for him during chemo so I would advise caution for someone who is actively treating.
I often find that when I feel like I am catching something I can take lots of Vitamin C, take a really hot soak to detox, and get into bed early and wake up better the next morning.