It’s the perfect excuse to enjoy a cup of coffee during the day and a glass of wine in the evening. Both together can make you feel less sleep deprived than if you took either alone.
It is known that coffee during the day can make it harder to fall asleep.
But one study suggests that drinking an alcoholic drink before bed can also help you sleep longer, offsetting some of the effect of the caffeine.
Meanwhile, an evening drink can lead to poor quality sleep, but coffee could make this easier, by increasing alertness.
The best night’s sleep is always achieved by avoiding both coffee and alcohol.
An evening drink can lead to poor quality sleep, but coffee can make this easier to deal with by increasing alertness
But for those who can’t resist, the new research suggests that coffee during the day and an evening drink can help balance each other out.
The findings come from a six-week study of 17 people, which found that each small daily cup of coffee or a similar caffeinated drink reduced the average amount of sleep a person got by about 10 minutes a day – or an hour a week.
However, for every cup, plus a standard alcoholic drink a person drank per day, the results suggest he or she would see a reduction in sleep of around just five minutes per day, or half an hour per week.
An alcoholic drink, which tends to increase drowsiness, could therefore offset some of the effect of a cup of coffee earlier in the day.
The study found that each additional standard alcoholic drink per day, such as a small glass of wine or half a pint of beer, caused a more restless night’s sleep, based on people’s ratings of how well they slept from zero to 100.
But if they also drank caffeine that day, people rated their sleep quality less poorly.
Researchers believe coffee may help mask daytime sleepiness caused by alcohol’s effect on sleep.
Frank Song, who led the research at the University of Washington, said: ‘We see evidence that people are drinking coffee and alcohol in an attempt to ‘balance’ their sleep.
‘Drinking alcohol after coffee can make it easier to fall asleep, and coffee can make people feel less sleepy if they drink alcohol later in the day.
‘However, they should be aware that they are still likely to get poorer quality of sleep, and both alcohol and caffeine are generally best avoided.’
The study, published in the journal PLOS One, looked at financial traders as an example of busy, working people who often rely on both caffeine and alcohol.
Every day for six weeks, the male volunteers completed a daily survey, including how long and how well they slept.
The apparently positive effect of alcohol being a sedative that causes drowsiness is that people lost less sleep after drinking it with caffeine, rather than drinking caffeine alone.
The more negative effect is that alcohol suppresses the important REM (rapid-eye-movement) sleep at the beginning of the night, making sleep worse after a drink.
But although people rated their sleep three points worse on the 100-point scale after each drink of alcohol, this effect was somewhat reduced for each small cup of caffeinated drink they drank on the same day.
Caffeine, which stays in the body for hours, can mask the drowsiness a person feels after a bad night’s sleep following a nightcap.
The study only looked at the sleep duration and quality that people reported, rather than using sleep trackers, so more research is needed.
Researchers also didn’t track exactly when people consumed caffeine or alcohol in a day.
But they conclude that the results may help explain why people ‘self-medicate’ with both alcohol and coffee to feel less tired.