Caffeine has no advantage after 3 nights of sleep restriction
A new study published in journal Sleep found that after restricting sleep to 5 hours per night, use of caffeine does not improve alertness or performance after three nights.
Researchers found that caffeine loses its ability to improve alertness and performance after just three nights of poor sleep.
Two cups of coffee a day was helpful to maintain performance for two days even after getting less than five hours sleep a night.
But by the third night onwards, coffee lost its effectiveness and those who were sleep deprived struggled to stay alert and became increasingly grumpy.
‘We were particularly surprised that the performance advantage conferred by two daily 200 mg doses of caffeine was lost after three nights of sleep restriction,’ said lead author Tracy Jill Doty, PhD, research scientist at Walter Reed Army Institute of Research.
‘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.’
A shot of espresso has 75 mg of caffeine while a regular cup of strong coffee around 200 mg.
To improve performance, proper sleep may be more important than a few cups of coffee (caffeine) !
