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Drinking a coffee before taking a quick catnap could improve the performance and alertness of people who work nightshifts and counteract sleep inertia, new research from the University of South Australia has found.

The small pilot study tested the impact of 200 milligrams of caffeine (equivalent to 1-2 regular cups of coffee) consumed by participants right before a 3.30am 30-minute nap, then compared the results with a group that took a placebo.

Participants taking a ‘caffeine-nap’ showed significant improvements in both performance and alertness, indicating the potential of the combination to counteract sleep grogginess.

Lead researcher Dr Stephanie Centofanti, from UniSA’s Sleep and Chronobiology Laboratory, believes the finding could help counteract sleep inertia commonly experienced by shiftworkers.

In Australia, more than 1.4 million people work shift work, with more than 200,000 routinely working night or evening shifts.

“Shift workers are often chronically sleep-deprived because they have disrupted and irregular sleep patterns,” Dr Centofanti says.

“As a result, they commonly use a range of strategies to try to boost their alertness while on nightshift, and these can include taking power naps and drinking coffee – yet it’s important to understand that there are disadvantages to both.”

Dr Centofanti suggests many shiftworkers who nap during a night shift when they feel tired experience ‘sleep inertia’ – grogginess after just waking up – which can impair their performance and mood for up to an hour after the nap.

Caffeine is also used by many people to stay awake and alert, but similarly, Dr Centofanti says too much can harm a person’s overall sleep and health and points out that it takes a while for its benefits to kick in.

“If you use it to perk you up after nap, it can take a good 20-30 minutes to kick in, so there’s a significant time delay before you feel the desired effect.”
Researchers found drinking a coffee followed by a catnap provided an unlikely combination that could improve attention and reduce sleep inertia.

“A ‘caffeine-nap’ (or ‘caff-nap’) could be a viable alternative,” Dr Centofanti says.

“By drinking a coffee before taking a nap, shiftworkers can gain the benefits of a 20-30 minute nap then the perk of the caffeine when they wake. It’s a win-win.”
Dr Centofanti says the study revealed a promising fatigue countermeasure for shift workers and that the next step for researchers would involve testing more people to strengthen results.