Headache when it rains? You may have 'weather change sickness'

The rainy season is coming to Japan. And for some people that means feeling a bit sick, with headaches and other body discomfort.
The cause may be "weather change sickness."
It's not the official name for the symptoms, but it's starting to become commonly used in Japan. We'll explain what the condition is and how to deal with it.

Symptoms of weather change sickness

We asked people on the street about weather change sickness and found more than few who are suffering from it.

This woman says she starts to get a headache soon after she wakes up, and then she knows rain is coming.
Others also say when it rains they feel dopey, or have diarrhea.

Dr. Sato Jun of Aichi Medical University Hospital is an expert on weather change sickness.

Aichi Medical University Hospital has a patient department dedicated to weather change sickness.
Dr. Sato Jun has studied the relations between sickness and weather and its mechanisms for over 30 years.
Patients from across Japan come to the hospital to seek help. Most come at this time of the year, when the rain season is about to start.

"Now is the worst time for people with weather change sickness. From spring to the rainy season there's change in atmospheric pressure, temperature, and humidity," Dr. Sato says.

A patient says her condition is so bad she even has to take time off work. But since she started seeing Dr. Sato, taking Chinese herbal medicine, and exercising, her symptoms have eased. She says she feels better now that she knows the cause of her sickness.

How it works

Dr. Sato says atmospheric pressure is the trigger for weather change sickness. That's picked up by a sensor in your ears that maintains your balance.

When it senses the pressure change, it stimulates the nerves that send out a neural transmitter substance.
That leads blood vessels in the brain to expand and release inflammatory substances, causing headaches.
Stiff shoulders and a sense of fatigue are also triggered by the inner ear sensing change in atmospheric pressure and disturbing the autonomic nervous system.

How to tell you may have it

Dr. Sato came up with this checklist from symptoms that were common to his patients.
He says you may be suffering from weather change sickness if you have more than 5 of the signs.

See a doctor before you decide

Dr. Sato also warns to not rely on medicine too much. "After taking medicine for a while, there are cases where people get more headaches. If your headache lasts two to three days, you should first consider the possibility there may be some problem in your brain. Once an examination has eliminated that possibility, then you may judge if you have weather change sickness."

How to prepare

A weather company in Japan has started offering predictions on weather change sickness. The forecast shows four levels indicating your risk of experiencing symptoms based on the change in atmospheric pressure.

Dr. Sato recommends exercises to improve blood flow around your ears and adjust the autonomic nerve.
Stretch the upper, middle, lower part of your ears, spending 5 seconds on each area. Giving both a 5-second pinch may also help.

Sato also says if you're suffering from lasting effects, make notes on the weather and the symptoms to tell your doctor.