I have used my portable far infrared sauna for over a year now and have found I need to heat my core energy temperature (due to low blood pressure) through a cup of hot tea or exercise before using my sauna in order to start sweating out the toxins. At first I was starting out at at level 4 (pretty hot) in order to start sweating and then I figured I was litterly roasting myself (like a turkey) and had to heat up my core temperature first. Now, I exercise first and then get right into the sauna and do 10 minutes on 3 and 30 minutes on 2 and it works great.