What Causes Fluctuations In Body Temperature And Pulse Rate?

Thank You. Can anything be done with low body temperature, usually around 96.1, sometimes a bit lower. I also have a slow pulse rate around 69. I have been tested for thyroid, seemingly in the normal range. Can the body temperature be raised to a normal 96.8? Is it unhealthy to have a low body temperature? I appreciate your help.Gerri