Caffeine, the word can conjure up a lot of mixed reactions ranging from ‘I love my morning fix’ to ‘it’s a poison that’s sure to kill you’.
Don’t you just love the world of hyperbole?
But what’s often overlooked is caffeine’s possible impact on sleep and sleep quality. Is there any truth to the notion that caffeine can interfere with sleep, even when people claim they can have a coffee and go to bed and not be affected?
Caffeine and sleep. Are the two poor bed fellows?
While it’s true that caffeine is habit forming, that, in and of itself, doesn’t automatically mean it’s ‘bad’. Moderate caffeine consumption of up to 400 mg per day (or the amount in three, 8 ounce/250ml cups of coffee) has historically been deemed safe for the majority of people although current research in genomics suggests that this amount may be too much for about about half the population. Those who are genetically termed ‘slow metabolizers’ can’t breakdown and excrete caffeine as quickly as ‘fast metabolizers’ and are, therefore, at an increased risk for high blood pressure and cardiovascular disease.
You can determine whether or not you’re a fast or slow metabolizer with a simple genetic test using a saliva sample with Nutrigenomix. For more information, see the Sample Report for 45 Gene Test or the video.
Yours truly is a fast metabolizer.
New research has found that caffeine can disrupt sleep hours later
According to a new study in the Journal of Clinical Sleep, drinking coffee in the early evening or late afternoon may disrupt sleep and sleep quality at the end of the day, hours after that cup of joe was chugged. Lead author Christopher Drake states that his study is the first of its kind to assess the impact of a particular dose of caffeine given at different times throughout the day before retiring for the night.
In this current study, 12 healthy volunteers were asked to keep their normal sleep schedules. Researchers then provided the subjects with 3 pills to take each day for 3 days; one of the pills was taken 6 hours before bed, one was taken 3 hours before bed, and the last pill was taken at bedtime.
For two of the days, one of the 3 pills contained 400 mg of caffeine (the equivalent of three, 8 ounces/250 ml cups of coffee; not to be confused with what’s considered to be a ‘small’ coffee today at most coffee chains) and the other two pills were placebos (caffeine free). On the other day of the experiment, all 3 pills were placebos.
The subjects had no idea what was in each pill; they were ‘blinded’ to this information to prevent any bias or influence from knowing what it was they were taking.
Sleep disturbance was measured objectively using a sleep monitor and subjectively from sleep diaries kept by the participants.
The results showed that ‘consuming caffeine 3, and even 6 hours, before bedtime significantly disrupts sleep, it reduced objectively measured total sleep time for the night by more than 1 hour’
Interestingly, subjective measures were not affected; the individuals who participated in the study didn’t notice a difference despite changes in brain waves.
Sleep specialists have long suspected that caffeine consumed later in the day could impact total sleep time and sleep quality; this makes sense since it takes between 5 to 6 hours to metabolize a given amount of caffeine by half. This would be consistent with general healthy advise not to consume caffeine-containing beverages after 3 pm or so.
For more information caffeine and health, check out Health Canada’s website