Experiencing hot flashes or waking up with night sweats in the days leading up to or during your period is a common phenomenon. This sensation of being excessively warm is not a sign of illness, but rather a normal, cyclical temperature fluctuation driven by changes in reproductive hormones. This regular adjustment in your body’s baseline temperature is a natural part of the menstrual cycle.
The Direct Role of Progesterone in Warming
The primary cause of this cyclical warmth is the hormone progesterone, which becomes dominant following ovulation. The ovarian follicle transforms into the corpus luteum, which secretes large amounts of progesterone during the luteal phase. Progesterone is thermogenic, meaning it generates heat and raises the body’s basal body temperature (BBT).
This hormonal surge causes a measurable increase in BBT, typically elevating it by about 0.5 to 1.0 degree Fahrenheit (0.3 to 0.7 degrees Celsius). This elevated temperature is maintained throughout the luteal phase, which generally lasts for about two weeks. The sustained increase in your core temperature is the underlying mechanism that creates the feeling of being hotter than usual. This temperature elevation persists until progesterone levels fall, signaling the start of menstruation.
How Hormones Affect the Body’s Thermostat
While progesterone is responsible for the temperature increase, its effect is mediated through the hypothalamus. This small region in the brain functions as the body’s thermostat, setting the ideal core temperature. The presence of elevated progesterone signals the hypothalamus to raise this thermal set point.
By raising the set point, the body conserves heat to match the new, higher temperature. Just before the period begins, the sharp drop in progesterone causes the thermal set point to suddenly fall back to its lower, pre-ovulation level. The body then rapidly dumps the excess heat, which can trigger sudden bursts of warmth, known as hot flashes, and intense sweating, especially at night.
Distinguishing Normal Heat from a Fever or Underlying Issue
It is important to distinguish this normal, cyclical temperature elevation from a true fever, which indicates an infection or illness. The progesterone-driven rise in basal body temperature is mild and temporary, resolving once menstruation begins. A true fever is usually a sustained temperature of 100.4°F (38°C) or higher, often accompanied by systemic symptoms like chills, body aches, or sore throat.
If you experience a significantly high temperature, such as 102°F (38.9°C) or more, or if the warmth is accompanied by extreme pain, heavy bleeding, or vomiting, medical consultation is necessary. Conditions like a thyroid disorder or Premenstrual Dysphoric Disorder (PMDD) can exacerbate cyclical temperature sensitivity.
Simple Strategies for Relief
Since this cyclical warmth is a natural hormonal event, relief focuses on managing symptoms and staying comfortable. Adjusting your sleep environment is effective, such as lowering the thermostat or using cooling sheets and pillows. Layering bedding allows you to quickly remove covers if a night sweat begins, preventing overheating.
Staying adequately hydrated is important, as drinking cool water helps lower your core temperature from the inside. Manage external triggers by avoiding spicy foods, alcohol, and caffeine, particularly before bedtime, as these substances stimulate heat production. Wearing loose-fitting clothing made from breathable materials like cotton or bamboo helps the body dissipate heat efficiently.