Late afternoon and early evening caffeine can disrupt sleep at night

A new study shows that caffeine consumption even six hours before bedtime can have significant, disruptive effects on sleep.

"Sleep specialists have always suspected that caffeine can disrupt long after it is consumed," said American Academy of Sleep Medicine President M. Safwan Badr, MD. "This study provides objective evidence supporting the general recommendation that avoiding caffeine in the late afternoon and at night is beneficial for sleep."

Results show that 400 mg of caffeine (about 2-3 cups of coffee) taken at bedtime, three and even six hours prior to bedtime significantly disrupts sleep. Even when caffeine was consumed six hours before going to bed, objectively measured total sleep time was dramatically reduced (more than one hour). However, subjective reports suggest that participants were unaware of this sleep disturbance.

The study is in the Nov. 15 issue of the Journal of Clinical Sleep Medicine, which is published by the American Academy of Sleep Medicine.

"Drinking a big cup of coffee on the way home from work can lead to negative effects on sleep just as if someone were to consume caffeine closer to bedtime," said lead author Christopher Drake, PhD, investigator at the Henry Ford Sleep Disorders and Research Center and associate professor of psychiatry and behavioral neurosciences at Wayne State University in Detroit, Mich. "People tend to be less likely to detect the disruptive effects of caffeine on sleep when taken in the afternoon," noted Drake, who also is on the board of directors of the Sleep Research Society.

Drake and his research team studied 12 healthy normal sleepers, as determined by a physical examination and clinical interview. Participants were instructed to maintain their normal sleep schedules. They were given three pills a day for four days, taking one pill at six, three and zero hours prior to scheduled . One of the pills contained 400 mg of caffeine, and the other two were a placebo. On one of the four days, all three pills were a placebo. Sleep disturbance was measured subjectively with a standard sleep diary and objectively using an in-home sleep monitor.

According to the authors, this is the first study to investigate the effects of a given dose of caffeine taken at different times before sleep. The results suggest that generally should be avoided after 5 p.m. in order to allow .

More information: "Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed," Journal of Clinical Sleep Medicine, 2013.

Related Stories

On March 11, spring forward without losing sleep

date Mar 06, 2012

(Medical Xpress) -- The return of daylight saving time and losing an hour of sleep causes most to cringe at the thought. According to Aparajitha Verma, M.D., medical director of the Sleep Disorders Center at the Methodist ...

Sleep tips for summer nights

date Jul 08, 2013

(HealthDay)—Those extra hours of daylight in the summer contribute to sleep problems experienced by many Americans, experts say.

Recommended for you

Why icing doesn't work to heal injuries

date 6 minutes ago

Applying ice to a muscle after injury is a commonly prescribed therapy for treating muscle bruises. But does it really speed recovery time and help the muscle to heal?

Sleep apnea during pregnancy is not good for mother or baby

date 23 minutes ago

Sleep apnea, a disorder in which breathing repeatedly stops during sleep, is a potentially serious condition because it deprives the body of oxygen. It becomes an even more serious condition in pregnant women—who ...

More reasons why getting a good night's sleep is important

date 29 minutes ago

Not getting enough sleep not only makes our minds less alert, but our bodies too. Studies have suggested that losing several hours of sleep can slow the body's metabolism, but what about losing only a few hours? A team of ...

Should we tax unhealthy foods?

date 29 minutes ago

What does a 20-ounce bottle of soda cost? If you said 99 cents, you are only partly right. While that may be the price on the sticker at the store, it doesn't take into account the cost to public health. One study, for example, ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.