Sleep Health | Sleep Review
A new study examining the effects of repeated sleep loss during a simulated work week found that consuming caffeinated coffee during the day helps minimize reductions in alertness and cognitive function compared to decaffeinated coffee.
While this effect occurred in the first 3 to 4 days of restricted sleep, no difference was seen between normal and decaf coffee drinkers on day five (the last day in the study). This suggests that coffee’s positive effects for people with impaired sleep are only temporary, the authors say.
“Previous research suggests that acute consumption of caffeinated coffee may reduce the effects of sleep deprivation on attention and cognitive deficits in the short term,” said Denise Lange, co-author of the study, in a press release. “This study is one of the first to investigate whether this effect can be translated into a real-life situation in which caffeinated beverages are often consumed daily by people with chronic sleep restrictions. Our study shows that moderate coffee consumption can mitigate some of the effects of decreased sleep for a few days. However, this is no substitute for a good night’s sleep in the long run. “
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The study was carried out at the Institute for Aerospace Medicine in Cologne. Twenty-six participants who carried a specific genotype of the gene coding for the adenosine A2A receptor were randomly assigned to groups who drank either caffeinated coffee (with 300 mg caffeine) or decaffeinated coffee under double-blind conditions. For five days, all participants’ sleep was limited to five hours per night, and each day they rated their subjective sleepiness and were tested for alertness, alertness, reaction time, accuracy, and memory.
The study was published in Progress in Neuro-Psychopharmacology & Biological Psychiatry.
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