température

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.

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With many North Americans turning to green tea for its touted health benefits, green tea powder has become a popular ingredient in many beverages. The beneficial compounds contained in the powder, however, may be more sensitive to heat and humidity than previously thought, reports a new study published in the Journal of Agricultural and Food Chemistry.

Researchers at Purdue University in Indiana looked at over 1,800 samples prepared from green tea powder, which were stored at varying temperatures and humidities for up to 16 weeks. Each sample was then analyzed to see how many catechins remained – the compound which gives green tea its beneficial antioxidants.

The researchers found that increased temperature, – and to a smaller degree, humidity – speed up the degradation of catechins.

"People drink green tea for health benefits, so they want the catechins to be present," said lead author Lisa Mauer. "The instant powder beverages are becoming more popular for consumers, and it’s important to know how storage can influence nutrition of your products."

Mauer hopes that the study results will help the industry develop better guidelines on how to store these powders.

Some green tea powder manufacturers recommend refrigerating the powder in an air-tight, light-tight container. When making tea, scoop out a serving and immediately replace the tin in the refrigerator. Once opened, they recommend using the powder within 2 to 4 weeks for maximum freshness and best taste.