A hot flash isn't your body overheating. It's your body responding to a false alarm. The hypothalamus — the part of the brain that regulates temperature — becomes more sensitive as oestrogen fluctuates, and narrows the range it considers comfortable.

Drift slightly above that narrowed range and the brain reacts as though you're genuinely overheating: blood vessels near the skin open, you flush, you sweat. The whole sequence usually lasts one to five minutes and then passes. That's why it comes from nowhere, and why the room temperature has so little to do with it.

It also explains the versions nobody warns you about — chills instead of heat, feet that dictate your whole body temperature, an internal thermostat that seems permanently set too high. It's the same regulation problem pointing in a different direction.

And if you don't get hot flashes at all: you can still be in perimenopause. Around a third of women never get them. Being told that heat is the symptom is one of the most common reasons women get sent home without help. If flashes disrupt your work or sleep, talk to a doctor about all your options including hormone therapy — a supplement is support during the transition, not a substitute for medical care.*