Monday, December 2, 2013

Caffeine: Yes No and In Between

The Journal of Clinical Sleep Medicine released a study this week examining the effects of caffeine on sleep. Specifically -- are timing and dose important?

If you must know -- yes, timing and dose matter -- but first I want to just explore what caffeine is.

Caffeine, at it's most basic, is a nervous stimulant. That is to say, it stimulates the nervous system, getting all of your neurons firing and excited. For some people this could be a jittery effect, others may feel more alert, and some others may not even notice a difference (I would direct you to read more about the study below). Tolerance to caffeine can occur over time. This means that you are more likely to notice the impact of caffeine if you do not regularly drink coffee and then one day have a rather large dose.

The study, (you can read the abstract here) examined a few different doses (0, 400 or 600mg), at a few different times - either at bedtime, three hours before bed, or six hours before bed. They found that yes, indeed, consumption of caffeine -- even six hours before bed -- can impact your sleep. In fact, the participants that had 400mg of caffeine (equivalent to about 2-3 cups of coffee) six hours before bed lost an hour of sleep! What's more -- subjectively, the participants didn't even seem to notice that they had lost that precious hour!

The study itself was small, only 12 participants, and very short term, only 4 days, but the findings are interesting, and certainly grounds for thought (excuse the pun), especially if you enjoy a cup of coffee on your way home from work or with your dessert.

What's the take-away here? Caffeine can impact your wakefulness and sleep cycles, even if you don't notice it. So if you choose to do so, make sure you have plenty of time before bed, lest you disturb your sleep cycle.

For a press release about the study, please see the American Academy of Sleep Medicine website at http://www.aasmnet.org/articles.aspx?id=4331

- Les, MS RD LD

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