This was interesting and somewhat surprising considering night sweats are a common complaint among perimenopausal women. However, what the researchers called the “lowest frequency” of menopause hot flashes was still substantial, considering it was five hot flashes in just one night of sleep. Based on an eight-hour night of sleep, that amounts to more than one hot flash every 90 minutes.
How to explain these results? Human core body temperature naturally follows a circadian rhythm, meaning that throughout the course of a 24-hour day, it naturally increases during the daylight hours until it peaks in the late afternoon/early evening (around 6:30 PM), then it declines to an all-time low in the early morning before the sun comes up. And, external factors—including physical exercise, emotional stress, being overdressed, an overheated house, sleeping with a warm bed partner and/or warm covers, and having an emotionally charged dream—all can raise core body temperature enough to trigger a cooling response, particularly if your zone of tolerance has narrowed.