Coffee Before Sleeping At Night Is Just Fine, But Cigarettes And Alcohol Will Reduce Your Sleep

Ever gone out for coffee well past dinner and then couldn't sleep when you got home? How annoying is that, am I right?

Well as it turns out, your inability to sleep may not be because of the coffee, but rather it could just all be in your head, according to a new study.

Researchers from Florida Atlantic University and Harvard Medical School say that drinking coffee or caffeinated tea just before bed doesn't affect the quality of your sleep at all. They studied 785 people for a total of 5,164 days and nights, analysing their sleep cycles while also recording how much caffeine, alcohol, and nicotine they consumed.

Their sleep was monitored using sleep diaries, as well as fitness trackers, recording how long they slept, their sleep efficiency, and how quickly they woke up after drifting off.

The study found that while nicotine and alcohol did disrupt sleep, caffeine did not. A pre-bed cigarette could take at least 42 minutes off your total sleep duration, especially bad for insomniacs, but coffee did nothing whatsoever.

"This study represents one of the largest longitudinal examinations of the associations of evening use of alcohol, caffeine, and nicotine with objectively measured sleep outcomes," Dr Christine Spadola of Florida Atlantic University said. "A night with use of nicotine and/or alcohol within four hours of bedtime demonstrated worse sleep continuity than a night without."

"We did not observe an association between ingestion of caffeine within four hours of bed with any of the sleep parameters."

Of course, the researchers were surprised at the result given previous beliefs about caffeine and sleep. And yet nicotine was the biggest culprit, with its use associated with an average 42.47-minute reduction in sleep duration.

It's not necessarily universal though. The data indicated that some people might in fact lose sleep over a nighttime cuppa. On average though, most people are unaffected.