There are 3 types of insomnia.
1. Difficulty falling asleep (hypnagogic disorder) - being unable to fall asleep for more than 2 hours after going to bed
2. Middle waking – Waking up more than 2 times before getting up in the morning
3. Early waking – waking up more than 2 hours earlier than a scheduled wake-up time
If you have any type of above conditions more than 2 times a week for more than 1 month, you are considered having insomnia.
One fourth of People aged 60 years or older wakes up during the night.
What kinds of diseases are caused by insomnia?
If you don’t sleep, ghrelin which is a type of hormone is secreted, resulting in obesity.
People who have insomnia have double possibility to have diabetes and high blood pressure.
What is a drink effective to improve the quality of sleep?
A drink contains theanine which increases alpha-wave in the brain according to the recent research.
Alpha-wave increases at the time of relaxation so increase of alpha-wave can improve the quality of sleep.
According to a research, waking-up time during the night of people intaking theanine decreased by 40 % compared to people not intaking theanine. Rested feeling in the morning was also 20 % higher.
The drink containing theanine and effective to improve the quality of sleep is Green tea extracted by cold water.
It is important to extract green tea using not hot water but cold water.
When green tea is extracted by hot water, major extracted substances are caffeine, catechin, theanine and arginine. But when green tea is extracted by cold water, only theanine and arginine are extracted. Caffeine is hardly extracted.
0.5 degrees C (33 degrees F) is most effective, so it is better to use iced water to extract.
It is important to slowly extract green tea in iced water for 2 to 3 hours. It is effective to drink a glass of the green tea 1 hour before going to bed.