I am 51 years old, yes fall into the hot flash age bracket. But... My hot flashes as one may want to call them are very cyclical...every 42 minutes most of the time. Get them approx 3 times a year, lasts 3-5 weeks...day and night, lasts 3-6 minutes. Before the hot flash ...I am shivering, queasy, then hot, then have a headache. It is almost like an aura. My GP checked some blood work (lots of numbers and letters) indicative for couple of different tumors, and hormone levels...all normal. I am on levothyroxine for hypothyroid...levels fine. Are these age related hormonal hot flashes or do I need to get something else checked out?