Depending on coffee to wake you up each day is the wrong answer for your chronic daytime sleepiness. A new study reports that caffeine’s effect on alertness and performance dwindled after 2 days.

Participants in the study were restricted to 5 hours of sleep per night for 5 nights. Each day they were given 200 mg of caffeine at 8 a.m. and again at noon. While awake they completed hourly cognitive tests.

Results show that caffeine improved performance only for the first two days of the simulated work week.

During the last 3 days of sleep restriction, alertness and performance declined. Those in the coffee group also rated themselves to be “more annoyed” than those in the placebo group over the final days of the study.

The research was conducted by the Walter Reed Army Institute of Research. Results were presented in June at the SLEEP 2016 annual meeting in Denver.

This study is a reminder that caffeine is no substitute for a good night’s sleep! The American Academy of Sleep Medicine recommends that adults should sleep 7 or more hours per night on a regular basis to promote optima