If you've had one, there's no mistaking it: the sudden, intense, hot feeling on your face and upper body, perhaps preceded or accompanied by a rapid heartbeat and sweating, nausea, dizziness, anxiety, headache, weakness, or a feeling of suffocation. Some women experience an "aura," an uneasy feeling just before the hot flash that lets them know what's coming. The flash is followed by a flush, leaving you reddened and perspiring. You can have a soaker or merely a moist upper lip. A chill can...