A hot shower on a cold morning is just one of many common habits that can result in a headache, reports the Daily Mail.
"In all headaches, and that includes migraines, the physiological explanation is the same," explains neurologist Giles Elrington.
"An electrical circuit at the back of the brain – known as the trigemino-cervical neurovascular pathway – fires off incorrectly, generating pain in the head. Think of a fire alarm ringing without the fire."
While it may feel comforting to get into a scalding shower on a chilly day, the sudden change in temperature is thought to affect blood pressure. Although the discomfort is usually short-lived, blood pressure changes in the head can bring on a sharp, stabbing pain.
"Cold extremes – such as swimming in cold water or eating ice-cream – may also trigger the pain," adds neurologist Michael Gross.
Other everyday events can trigger headaches or make migraines worse. Not getting enough sleep, too much exertion, foods high in preservatives, tight hairdos, cigarette smoke, warm weather and even sex are all thought to be possible contributors to headaches.