Читать книгу Sleep: The secret to sleeping well and waking refreshed - Prof. Idzikowski Chris - Страница 60

Caffeine is a very powerful stimulant that is known to cause the delay of sleep onset. Studies have shown that a dose equivalent to one cup of coffee taken at bedtime can both increase the time taken to fall asleep and decrease sleep quality, especially in non-REM deep sleep (see page 19). In a few individuals, a dose of coffee in the morning can also have an effect the following night, indicating that extremely low concentrations of caffeine can affect sleep. Like all stimulants, caffeine may make you feel increasingly alert during the day, but, as well as causing insomnia, prolonged, high-dose usage (more than six cups of coffee a day) can lead to the following nasty side-effects: