Hot Flashes & Night Sweats

Sudden waves of heat, flushing, and sweating, including the night sweats that disturb sleep, are a familiar experience around the menopause transition. They can have other causes too, so they are best understood in context. This page explains the possible links and why a clinician's assessment matters more than self-diagnosis.

How hot flashes can relate to hormones

The body keeps its core temperature within a narrow range, and the brain region that manages this is sensitive to changing hormone levels. As ovarian hormone production shifts around menopause, this temperature control can become more reactive, so small changes trigger the sensation of sudden heat, flushing, and sweating that people call a hot flash. When this happens during sleep it is felt as a night sweat.

These episodes are extremely common during the menopause transition and are a normal part of that process for many people. Because similar sensations can arise for other reasons, a hot flash is best understood as a clue rather than a diagnosis.

Which hormones and conditions may be involved

Several factors can contribute. None can be diagnosed from the symptom alone, but a clinician may consider:

• The menopause transition. Changing oestrogen levels are the most common reason for hot flashes and night sweats.
• Thyroid hormones. An overactive thyroid can cause heat intolerance and sweating that may feel similar.
• Other hormonal changes. Some treatments that lower sex-hormone levels can also produce flashes.
• Blood sugar. Low blood sugar can cause sweating and a flushed, unwell feeling.

Blood tests a clinician might consider

Around the typical age of menopause, hot flashes are often diagnosed from the history alone without routine hormone testing. When the picture is less clear, a clinician might consider:

• Thyroid tests such as TSH if thyroid overactivity is suspected.
• Sex-hormone tests in specific situations, interpreted carefully because levels fluctuate.
• Blood glucose if sweating episodes suggest a blood-sugar cause.
• General tests when night sweats are persistent and unexplained.

You can read more about individual tests in our blood tests section and about the messengers themselves in the hormones section. Related conditions are covered in the conditions section, and options are discussed in treatments. See also cold or heat intolerance.

Non-hormonal causes to keep in mind

Not every flush or sweat is hormonal. A warm room, spicy food, alcohol, caffeine, anxiety, fevers and infections, and certain medicines can all cause flushing or sweating. Persistent night sweats that soak through bedding, especially with weight loss or feeling unwell, deserve medical attention because they can occasionally signal other conditions. Because these explanations are common, a careful history usually comes first.

When to see a clinician

It is reasonable to seek medical advice when hot flashes are frequent or disruptive, when night sweats are drenching or persistent, or when they come with other symptoms such as unintended weight loss, fevers, or feeling unwell. A clinician can take a history, examine you, and decide whether any tests are warranted, and can discuss options for managing bothersome symptoms. This page is educational and is not a substitute for personalised medical advice.