Do your hot flashes make you feel like your body is a five-alarm fire? Hot flashes can be so strong that women have been known to stand in front of the refrigerator with the door open or even stick their head in the freezer! According to Robert Freeman, a researcher at Wayne State University, hot flashes are more likely to happen in the morning or in the evening, and while most hot flashes last about five minutes, the cascade of events that lead up to the ultimate unpleasantness often take twenty minutes or more.