context: There's a reason why menopause comes to mind when you hear the words "hot flash." Over 75% of menopausal women do feel the heat. But that's not the only reason you could lose your cool. It could be a reaction to spicy food or signs of an illness. And you don't have to be female to have one. Men get them, too. The technical term is vasomotor symptom. It comes along with a drop in your body's level of the hormone estrogen. Another name you might hear is night sweats. They are hot flashes that wake you up after you've gone to bed. For most people, a hot flash isn't just a rise in body temperature, it's a mix of things: A sudden warmth that's most intense across your head and chest Reddened skin Sweating, either light or heavy Rapid heartbeat Anxiety Flashes aren't just a menopause thing, but that is when you're most likely to have them. They differ from woman to woman, but they start before or during menopause. There are no rules for how often they hit or how long they last. You might have several a day or none. They can last anywhere from 30 seconds to 10 minutes. They can happen once an hour or once a day. There's no rule for how long you'll have them, either. For years, the answer was 6 months to 2 years. But a new study of women nationwide says it may be more like 7 to 11 years. Plus, the earlier into menopause you start to have them, the longer they're likely to continue. You might also have them longer if you smoke, are overweight, stressed, depressed, or anxious. Your heritage can also play a role. African- American women have them for about 11 years. But for Asian women, it's about half that time. Things that can set off a menopausal hot flash include: A workout in hot weather Spicy food Alcohol Smoking Hot weather Tight clothing Stress Eating a lot of sugar Whether it's a symptom or medication side effect, these health conditions -- or their treatments -- can also lead to hot flashes. Breast cancer. Treatments like chemotherapy, radiation, ovary removal, and antiestrogen therapy can bring on what's called chemical menopause. And with it comes lower estrogen levels and symptoms like hot flashes. Hot flashes that result from breast cancer treatment can be more frequent and severe than natural ones. If you've been through menopause already and had hot flashes then, you'll probably get them again if you take tamoxifen to treat your cancer. They'll be about as severe and happen about as often as the first time around. Pregnancy or recent childbirth. There's a lot we don't know about hot flashes, and the fact that they can happen to menopausal women as well as expectant and new mothers proves how mysterious they are. Once study found they peaked at week 30 for pregnant women and week 2 after giving birth for new moms. But as with menopause, this is a time when hormone levels shift dramatically and women put on extra weight. Multiple sclerosis ( MS). Heat can make your symptoms worse, whether it's hot and humid outside or you have a fever. You might notice what's called Uhthoff's sign, changes in vision when you get too hot. Any problems should go away once you cool back down. Some people with MS also have hot flashes that aren't linked to hormones. Your doctor might call them paroxysmal symptoms. It sounds scary, but it just means your autonomic nervous system, which controls your organs, blood vessels, and some muscles, isn't working like it should. Let your doctor know. Prostate and testicular cancer. Men with prostate cancer sometimes get a treatment called androgen suppression therapy. It lowers their levels of the hormone testosterone, which helps radiation therapy work better. But it can also cause hot flashes. If your treatment is temporary, the flashes should go away a few months after it stops. But for some men, it's permanent. Your doctor will prescribe medications to ease your symptoms. Men who've had their testicles removed to treat cancer may also get hot flashes. Thyroid disease. When your body creates too much thyroid hormone (your doctor will call this hyperthyroidism) it can really turn up the heat. It might even bring on early menopause (before you turn 40 or in your early 40s). There are medications to treat this problem. Once you get it under control, your hot flashes will ease up. Menopause might get back on schedule, too.