I have at times a sudden rise in body temperature thats comes on at random times and completely out of the blue. It mostly happens in the evening for no apparent reason. These hot flushes seem to happen for a short period and quickly go. I am a male in my mid-forties with resonable fitness. I don t sweat during these times of increased body temp. I ve been experiencing these symptoms over the last couple of years. I been working nights for 6 years.