Is Caffeine Disrupting Your Sleep?

Caffeine is a stimulant and most doctors will tell you to avoid it before bedtime. Yet, many people drink several cups of coffee between dinner and bedtime and they fall asleep without any problems. The point is, does it really matter if you have just a little bit of caffeine-containing chocolate dessert before you go to bed at night? According to a recent study, the answer depends upon your physiological vulnerability to developing insomnia (difficulty falling asleep).¹

A previous study showed that people that scored higher on the Ford Insomnia Response to Stress Test (FIRST) had more objective difficulty falling asleep in an overnight sleep lab … something so simple as an unfamiliar environment messed up their sleep.² The FIRST consists of a simple nine-item questionnaire that asks how likely a given situation (such as watching a frightening TV show or preparing for a vacation) will have on one’s ability to fall asleep that night.

Researchers at the Henry Ford Hospital in Detroit, MI, evaluated the impact of a low dose of caffeine (roughly two cups of coffee) in two healthy groups of subjects. One group in the “caffeine” study had a low score on the Ford Insomnia Response to Stress Test (FIRST) and the other had an elevated score on this test. Study participants were specially selected so that none of them had any difficulty falling asleep (each group took about 15 minutes to fall asleep), despite the differences in FIRST scores.

Then on a different night, subjects were given a caffeine pill one hour prior to their normal sleep time. People with low FIRST scores took only an additional five minutes to fall asleep (not significant), while people with high FIRST scores took over 60 minutes to fall asleep. In other words, the latter group exhibited insomnia when exposed to a relatively low dose of caffeine.

Based on the foregoing studies, the authors state, “… small but otherwise benign stimuli may trigger insomnia. This notion is consistent with the observation that some individuals (~22%) are unable to identify a specific stressor that they believe can account for the onset of their insomnia symptoms.”

If you take more than 20 minutes to fall asleep, you may not be able to identify a single factor as the cause. It could be that you are just more vulnerable to the sleep-disrupting effects of all forms of stimuli. You may be what people commonly refer to as a light sleeper. Solely omitting nighttime caffeine may not be enough. You may also need to maintain a rigid sleep schedule with a regular bedtime routine and make sure that you are sleeping in a comfortably supportive bed. Patients responding to Fibromyalgia Network’s 2004 survey rated this approach to sleep as the third most popular nondrug therapy.

1. Drake CL, et al. Sleep Medicine 7:567-72, 2006.
2. Drake CL, et al. Sleep 27(2):285-91, 2004.