Reaching for a cup of coffee or taking a brief nap are two proven ways to combat tiredness while working nights.
But research has found they may be counterproductive. This is because they can lead to even more tiredness and make it harder to sleep once you go to bed. And as tired workers make mistakes, they can also result in an increase in workplace accidents.
This is important because about 25 per cent of North America’s workforce is engaged in shift work, a figure that is expected to rise in today’s gig economy.
But the constant changes in schedule can upset a worker’s circadian rhythm — a natural process that regulates the sleep-wake cycle. This, in turn, can lead to sleep deprivation, disruption of family and social life, insomnia and even heart disease.
Although napping and drinking coffee are common energy boosters, they can also be potential hazards. Drinking too much coffee can cause further sleep deprivation, while naps can result in sleep inertia — the feeling of fatigue in the hour following.
While coffee can help increase alertness, it takes 20 to 30 minutes to reach the peak effect, which means it might not be as useful when consumed after a nap.
Drinking coffee before a nap is key
But what happens when coffee is consumed before a nap? A new pilot study published in The Journal of Biological and Medical Rhythm Research tries to find out.
Six day-shift workers recreated their routines in a sleep laboratory over two 36-hour visits. Five minutes before a 30-minute nap, they drank 200 mg of caffeine, the equivalent of one to two regular cups of coffee, or the same amount of decaffeinated coffee.
Researchers found the “caffeine-nap” resulted in less fatigue and improved alertness in the 45 minutes following, compared with when the workers drank decaf. This suggests a caffeine-nap might be an effective way to reduce sleep inertia on the job.
However, as the study’s authors noted, the effects may depend on the individual’s sensitivity to caffeine and how easy he or she finds it to nap.
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