What are the symptoms of caffeine overdose?
Caffeine stimulates the central nervous system and can produce a variety of effects elsewhere in the body. The symptoms of a caffeine overdose (“caffeinism”) will vary, according to individual differences and the amount consumed. Doses ranging from 250 to 750 mg (2 to 7 cups of coffee or tablets of NoDoz) can produce restlessness, nausea, headache, tense muscles, sleep disturbances, and irregular heart beats. Doses of over 750 mg (7 cups of coffee) can produce a reaction similar to an anxiety attack, including delirium, ringing ears, and light flashes. These amounts of caffeine may come from a single dose or from multiple doses at short intervals. Besides caffeine’s effects, the essential oils of coffee may cause gastrointestinal irritation and diarrhea, and the high tannin content of tea can result in constipation. Caffeine and Sleep Studies of the effect of caffeine on sleep have shown that one strong cup of coffee, drunk 30-60 minutes before going to sleep, can cause restlessness an
