What Causes Hot And Cold Flashes Simultaneously?

I've struggled with hot flushes followed by extreme cold flushes throughtout the day and at night for 16 years. I live healthily and exercise and have tried all sorts. You see lots of info for hot flushes but as yet I have been unable to find the help I need. My Dr. says it is hormones and can go on until I am 70. Could it be something else? Thanks. Margy