The hot flash has almost become synonymous with menopause. And rightly so – it is one of the most common menopause-related symptoms.
Up to 75 percent of North American women experience hot flashes during peri-menopause. This number is even higher (90 percent) among U.S. women who have had undergone a hysterectomy. While hot flashes are very common, women experience hot flashes differently and in varying degrees of severity.
What Does a Hot Flash Feel Like?
If you haven’t experienced a hot flash, imagine it as a rapid, spontaneous feeling of warmth, often to the point of sweating a great deal. Typically, your face, neck, and chest feel the most heat, then immediately afterward you might swing to being chilled. The amount of time between hot flashes varies by person but can range from one or two hot flashes per day to one an hour, and each one typically lasts a few minutes. When these hot flashes strike at night and result in sweating, they are called night sweats.
Hypothalamus and the Heat From Within
During peri-menopause, your body’s “thermoneutral zone” narrows. The “thermoneutral zone” is a range of temperatures that is considered “neutral” by your body. Typically, the “thermoneutral zone” is fairly wide, but during peri-menopause, the zone narrows. This means that your body detects feelings of being overheated or overly cold more sensitively than usual.
When your body detects that your body is overheated outside of the “thermoneutral zone”, your body works in overdrive to cool you down. (The specific portion of your brain called the hypothalamus is what regulates body temperature.) To cool down, the hypothalamus tells the blood vessels near your skin to expand, allowing more blood to flow through them and letting out heat in the process. This excess heat from blood flow is what leads to sweating, which also helps your body begin to cool off (just like when you sweat during exercise, except it’s triggered by your hypothalamus rather than by physical activity).
Unfortunately, scientists are not sure why the “thermoneutral zone” is so narrow during peri-menopause, but the physical response is the same one that’s in place to protect us from dangerous overheating.