According to The Telegraph, researchers have discovered that caffeine eventually loses its ability to improve alertness and concentration.
The experiment, involving 48 healthy participants, found that two cups of coffee helped people maintain their performance for two days after less than five hours of sleep per night.
However, by the third night, the same people on the same amount of sleep struggled to concentrate and became increasingly moody despite consuming caffeine.
Speaking about the findings, Dr. Tracy Jill Doty of the Walter Reed Army Institute of Research, said:
“We were particularly surprised that the performance advantage conferred by two daily 200mg doses of caffeine was lost after three nights of sleep restriction.”
“These results are important because caffeine is a stimulant widely used to counteract performance decline following periods of restricted sleep.
“The data from this study suggests that the same effective daily dose of caffeine is not sufficient to prevent performance decline over multiple days of restricted sleep.”
In other words, you might find that your three cups of coffee by lunchtime on Mondays won’t quite give you the same kick after a Friday, Saturday, and Sunday on the town interrupted sleep.
