A hot flash is a sudden wave of heat that spreads through your upper body, typically your face, neck, and chest, lasting anywhere from a few seconds to several minutes. It happens when your brain’s internal thermostat malfunctions, usually due to shifting hormone levels, and triggers your body’s cooling mechanisms at the wrong time. About 3 in 4 people experience hot flashes in the years surrounding menopause, but they can also affect men and younger people under certain circumstances.
What Happens in Your Body During a Hot Flash
Your brain constantly regulates body temperature within a narrow comfort zone. Below the bottom of that zone, you shiver. Above the top, you sweat. In between, your body makes small adjustments by changing blood flow to your skin. This comfort zone is normally wide enough that minor temperature shifts don’t trigger a major response.
When estrogen levels drop, as they do during perimenopause and menopause, the brain’s temperature-regulation center becomes overly sensitive. The comfort zone narrows dramatically, so even a tiny increase in core body temperature, one that wouldn’t have registered before, now crosses the upper threshold. Your brain interprets this as overheating and launches a full cooling response: blood vessels near the skin dilate (causing the flush and redness), sweat glands activate, and your heart rate can jump by 8 to 16 beats per minute. You feel a rush of intense warmth even though your actual body temperature has barely changed.
This narrowing of the comfort zone is driven by increased activity in the sympathetic nervous system, the same system responsible for your fight-or-flight response. Estrogen normally helps regulate the brain receptors involved in this process, so when estrogen withdraws, the system becomes unstable.
What a Hot Flash Feels Like
Most people describe the sensation as a sudden warmth rising through the chest, neck, and face. Your skin may visibly redden, and you might break into a sweat that ranges from mild dampness to soaking through clothing. Some people feel anxious or have a racing heart during an episode. Afterward, as your body overcorrects, you may feel chilled. The whole experience typically lasts one to five minutes, though the lingering discomfort can take longer to fade.
When hot flashes happen during sleep, they’re called night sweats. The underlying mechanism is the same, but the effect on sleep quality can be significant. You may wake up drenched, needing to change clothes or sheets, and the repeated disruptions can lead to chronic fatigue, irritability, and difficulty concentrating during the day.
How Long Hot Flashes Last
Hot flashes most commonly begin during perimenopause, the transitional years before menstruation stops entirely. For some people, they last only a few months. For others, they persist for years, sometimes continuing well past menopause. There’s no reliable way to predict how long yours will last, but the intensity and frequency tend to change over time, often peaking in the first year or two after the final menstrual period before gradually tapering.
Causes Beyond Menopause
Menopause is the most common cause, but it’s far from the only one. Hot flashes can be triggered by anything that disrupts hormonal balance or affects the brain’s temperature regulation.
- Cancer treatments: Chemotherapy, hormone therapy, and certain medications used in cancer care frequently cause hot flashes. Men undergoing prostate cancer treatment are particularly affected, since these treatments often suppress testosterone or involve estrogen-based drugs.
- Medications: Drugs prescribed for anxiety, depression, high blood pressure, and infertility can all trigger hot flashes as a side effect.
- Thyroid disorders: An overactive thyroid raises your metabolic rate and can produce symptoms that closely mimic menopausal hot flashes.
If you’re experiencing hot flashes and you’re not in the typical age range for menopause, or if you’re male, it’s worth investigating other possible causes rather than assuming they’ll resolve on their own.
Common Triggers That Make Them Worse
Even when the underlying cause is hormonal, specific foods and habits can increase the frequency or intensity of episodes. Caffeine is one of the most common culprits. It stimulates the nervous system in ways that can provoke hot flashes and night sweats, creating a frustrating cycle: poor sleep leads to more coffee, which leads to more night sweats, which leads to worse sleep.
Alcohol, especially more than one drink per day, increases both the frequency and intensity of hot flashes. Spicy foods can set off individual episodes. Even drinking hot beverages, regardless of caffeine content, can be enough to push your body past that narrowed temperature threshold and trigger a flash. Tight clothing, warm rooms, and emotional stress are also well-known triggers.
Treatment Options
Hormone therapy remains the most effective treatment for menopausal hot flashes. It works by replacing the estrogen your body has stopped producing, which widens the thermoregulatory zone back toward its normal range. However, hormone therapy carries risks that vary depending on your age, health history, and the type of hormones used, so it’s not right for everyone.
For people who can’t or prefer not to use hormones, the FDA approved a new option in 2023: a medication called Veozah (fezolinetant) that works directly on brain receptors involved in temperature regulation. It blocks a specific receptor that plays a key role in triggering hot flashes, without using any hormones. In clinical trials, it significantly reduced the frequency and severity of moderate to severe hot flashes. It’s a once-daily pill, though it requires liver monitoring because it can cause elevated liver enzymes in some people. Other potential side effects include abdominal pain, diarrhea, insomnia, and back pain.
Some antidepressants, originally developed for mood disorders, also reduce hot flash frequency and are sometimes prescribed off-label for this purpose. Lifestyle adjustments like dressing in layers, keeping your bedroom cool, reducing caffeine and alcohol, and managing stress can meaningfully reduce how often and how severely hot flashes hit. These strategies won’t eliminate them entirely for most people, but they can make the difference between disruptive episodes and manageable ones.