I have fairly severe sciatic pain in lower back near backbone area on both sides. I am a female, 87 years old and physically very active -sports & exercise classes. Is it safe to use the hot, cold, hot tratment and if so, what should the timing (minutes) be for each part. Have massaged the area with my fingers and this has helped quite a lot so should I just carry on with the heat/cold scenario, and if so, about how many minutes for each part. Thanks you for any help you can give as I lead a fairly active life and hope to continue doing so if I can get the pain reduced. Sheila M.