It is best not to drink coffee at night, but according to the nature of each person’s work to decide, for example, some people belong to the night work, drinking coffee at night may not have a significant impact on sleep. If the majority of people are working at night is to sleep, this time to drink coffee will cause excitement. Some will also appear to drink coffee after the tachycardia, panic, some will have nausea. Coffee is best to drink mainly during the day, and do not drink more than 2 cups of coffee per day, coffee time is best at noon or in the morning, do not drink coffee after night, but some journalists, ambulatory workers are mainly at night, coffee can be drunk at night.