How caffeine kills your sleep
16-04-2014
We all know that caffeine and sleep are not a good mix but new research suggests that it is worse than we previously suspected. Yes it is bad news for all those coffee drinkers out there, and there are a lot of us. In the past the general rule of thumb was that you should not ingest any caffeine four hours before bedtime. A new study has found that caffeine has a significant impact on your sleep if ingested up to six hours before you go to bed.
Caffiends
Chances are that at some point in the day you will ingest caffeine. Most of us like to start the day with a hot caffeine drink, be it coffee or most normal teas. Then during the day you may have some in your soft drink or even the chocolate bar you eat. Caffeine is found in many plants, it acts as a natural pesticide. Humans have been using it to wake up for many years, but the flip side is that while it can be useful at certain times of the day, its stimulating capacity can become a hindrance the closer to bedtime that we ingest it.
Six hours takes one hour off
A new study has found that any caffeine eaten or drunk within six hours of bedtime can reduce the length of sleep by an hour. You may be losing a precious hour of sleep because of that can of coke you have with dinner or because of that late night chocolate bar.
The study
We have known about the danger of caffeine near bedtime for a long time but this study was one of the first to really dig into the impacts. Published in the Journal of Clinical Sleep Medicine, the study looked at the impacts of around 400 milligrams of caffeine, which equates to about two or three normal cups of coffee, taken six hours before bedtime, three hours before bedtime and at bedtime.
The findings
Unsurprisingly they found that the caffeine had a negative impact on sleep when taken at bedtime and three hours before. More surprising though was that it also negatively affected people’s sleep when taken six hours beforehand.
“Even at six hours, caffeine reduced sleep by more than one hour,” Dr Drake, author of the study and member of the Henry Ford Sleep Disorders and Research Centre in Detroit stated, “The present results suggest the common practice of afternoon consumption of caffeine should at a minimum be restricted to before 17:00, particularly with regard to the moderate-large doses of caffeine commonly found in increasingly popular premium coffees and energy drinks.”
Drake and his research team used 12 healthy people with an average age of 39 for their study. They were asked to continue with their normal sleep schedules of going to bed between 11:00pm and 1:00am and waking up between 6:00am and 9:00am. They were then given three caffeine pills a day for four days and asked to have them at six, three and zero hours before they went to bed. The pills were a mix of 400 milligrams of caffeine and placebo, with the pill timings mixed up as the study progressed.
Each person filled in a sleep diary and they were hooked up to a monitor that recorded their EEG to detect sleep disturbance.
The take home
Losing an hour of sleep in a night might not sound like much but after only a few days this can start to have a range of serious consequences. 400 milligrams is not much caffeine, you should be safe with a weak cup of tea or a chocolate bar, but avoid coffee or soft drinks for at least six hours before sleep.
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