While drinking coffee helps many to Wake up in the morning and improve performance, British researchers found that after three nights of poor sleep caffeine loses its power. Poor sleep was defined as sleep for 5 hours a day or less. It was at this point, after three sleepless nights, caffeine can no longer improve the care and productivity of employees, experts say.
The researchers analyzed 48 healthy people who have not slept more than 5 hours per night for 5 days. Participants received either 200 mg caffeine or placebo twice a day. The researchers then conducted a series of cognitive tests with volunteers. “We were particularly surprised that the performance advantage provided by the two daily doses of caffeine 200 mg was lost after three nights of sleep restriction,” said Dr. Tracy Jill Doty, the lead author of the study. “These results are important because caffeine is a stimulant, widely used to overcome the performance degradation resulting from limited sleep.
