Caffeine and Sleep

Home >> Sleep Topics >> Caffeine and Sleep

Caffeine has been called the most popular drug in the world. It is found naturally in over 60 plants including the coffee bean, tea leaf, kola nut and cacao pod. All over the world people consume caffeine on a daily basis in coffee, tea, cocoa, chocolate, some soft drinks, and some drugs.

Because caffeine is a stimulant, most people use it after waking up in the morning or to remain alert during the day. While it is important to note that caffeine cannot replace sleep, it can temporarily make us feel more alert by blocking sleep-inducing chemicals in the brain and increasing adrenaline production.

There is no nutritional need for caffeine in the diet. Moderate caffeine intake, however, is not associated with any recognized health risk. Three 8 oz. cups of coffee (250 milligrams of caffeine) per day is considered a moderate amount of caffeine. Six or more 8 oz. cups of coffee per day is considered excessive intake of caffeine.

Caffeine enters the bloodstream through the stomach and small intestine and can have a stimulating effect as soon as 15 minutes after it is consumed. Once in the body, caffeine will persist for several hours: it takes about 6 hours for one half of the caffeine to be eliminated. There are numerous studies to support the idea that caffeine causes physical dependence. If you suspect that you or someone you know is dependent on to caffeine, the best test is to eliminate it and look for signs of withdrawal, such as headache, fatigue and muscle pain.

Although caffeine is safe to consume in moderation, it is not recommended for children. It may negatively affect a child's nutrition by replacing nutrient-dense foods such as milk. A child may also eat less because caffeine acts as an appetite suppressant. Caffeine can be safely eliminated from a child's diet since there is no nutritional requirement for it.

Although the FDA does not advise against women who are pregnant or nursing to eliminate caffeine from the diet, many experts recommend limiting the amount consumed during that time to one or two 8 oz. servings per day.


Caffeine is a stimulant. In moderate doses, it can:

  • Increase alertness
  • Reduce fine motor coordination
  • Cause insomnia
  • Cause headaches, nervousness and dizziness

It has also been known to result in:

  • Anxiety
  • Irritability
  • Rapid heartbeat
  • Excessive urination
  • Sleep disturbance
  • A "caffeine crash" once the effects wear off


If the conditions listed under "symptoms" occur, discontinue the use of caffeine. These effects are more likely to occur if caffeine is consumed in large doses. Children and women who are nursing or pregnant should avoid caffeine. People who are taking any prescription medication should talk to their doctors before consuming caffeine.

Knowing the caffeine content of your food and drinks can help you keep caffeine intake at a healthy level so you can still reap the benefits of a good night's sleep.


In order to sleep better at night and reduce daytime sleepiness, try practicing the following sleep tips:

  • Maintain a regular bed and wake time schedule including weekends
  • Establish a regular, relaxing bedtime routine such as taking a bath or listening to music
  • Create a sleep environment that is dark, quiet, comfortable and cool
  • Sleep on a comfortable mattress and pillows
  • Use your bedroom only for sleep and sex
  • Finish eating at least 2-3 hours before your regular bedtime
  • Exercise regularly but avoid it a few hours before bedtime
  • Avoid caffeine (e.g. coffee, tea, soft drinks, chocolate) close to bedtime
  • Don't smoke -- not only is it a major health risk it can lead to poor sleep
  • Avoid alcohol close to bedtime; it can lead to disrupted sleep later in the night


According to the 2001 Sleep in America poll, 43% of Americans are "very likely" to use caffeinated beverages to combat daytime sleepiness.

Reviewed by:

Greg Belenky, M.D.

Dr. Belenky received his B.A. degree in Psychology from Yale University and his M.D. degree from Stanford University. He completed an internship in internal medicine at the University of Utah, and a residency in psychiatry at Yale. Dr. Belenky is Research Professor and Director, Sleep and Performance Research Center, Washington State University Spokane. Prior to this he was Professor in the Department of Psychiatry of the Uniformed Services University of the Health Sciences and Director of the Division of Neuropsychiatry at the Walter Reed Army Institute of Research. He is a Colonel (retired) in the U.S. Army Medical Corps. He is a Fellow of the American Psychiatric Association, a member of the American Academy of Sleep Medicine, the Sleep Research Society and the European Sleep Research Society, and serves on the Board of Directors of the National Sleep Foundation. Dr. Belenky’s research ranges from basic to applied and includes sleep, sleep deprivation, and continuous operations; combat stress reactions and post-traumatic stress disorder; and the neurobiology of human behavior and adaptation. During the Gulf War (1990-91), he served as regimental psychiatrist for the U.S. Army’s Second Armored Cavalry Regiment. In addition to authoring multiple journal articles, he has edited two books on combat psychiatry (Contemporary Studies in Combat Psychiatry, Greenwood Press, 1987 and The Gulf War and Mental Health: A Comprehensive Guide, Praeger Press, 1996) and done pioneering work on sleep restriction and performance.