Is Coffee Really Bad for Sleep?

Research shows that coffee can reduce the quality and quantity of sleep.

Posted Dec 30, 2017

Coffee. A magical elixir that restores vigor and brightens the mood. The stuff America runs on. Nothing better than a damn fine cup of it. Something so wonderful that people pay thousands of dollars to get the best grinder and brewing technology. Frappuccino, cappuccino, and espresso. An effective countermeasure to drowsiness that improves driving safety. The daily ration that let the soldiers of old face another day on the battle field. A smart drug.  Something that protects the liver from cancer.  A mood lifter that decreases the risk of suicide. The one luxury good the average middle class person can easily afford. America even has a “national coffee day”.

Coffee. A stomach churning drink that leaves one anxious and stressed. Have some too late in the day and it will be hard to fall asleep. Too much and a sweaty feeling of panic comes over you. An addicting substance that, at best, just cures the hang over effect of the letdown of the previous day’s consumption. May cause high blood pressure. Can lead to aggressive driving and angry outbursts. A daily drain on one’s finances that will keep you from ever becoming a millionaire. A license to print money for owners of cafes. Something that draws together fringe people to discuss dangerous ideas that challenge the foundations of society.

Like our relationship with most psychoactive substances, coffee and its major ingredient, caffeine, have often had a conflicted relationship with society. No one knows when or how coffee was discovered but the plant itself originated in Africa. It was used by tribes in Africa long ago and was known to the Arabs and Persians since at least the middle ages. The first coffee house was started in Constantinople in 1554. Despite initial opposition from the Church coffee reached Europe by the early 1600s. When coffee houses were first introduced into European cities such as Oxford, London, and Paris in the mid-1600s, it was a jolt to society and they spread quickly, even reaching Boston by 1676.

In Europe and the American colonies of the early 1600s, water was often of poor quality and could even be dangerous to drink. At this time sanitary conditions were poor, modern plumbing had not been invented, and living conditions were generally difficult. As a result, rather than drinking potentially disease-laden water, alcoholic beverages such as beer were commonly consumed, even by children. Because of the processing required to produce alcohol it was a relatively safe way to consume fluid. Also the alcohol, to some degree, eased the stress and strain of daily life in a world not too far above subsistence living. Into that difficult and drowsy world came the cafes and this new drink, coffee.

By all accounts from the time, it had an electrifying effect. Clarity of thought, greater task focus, and more physical energy were available for the price of a cup of black fluid. Rather than the sloppy, slightly dreamy, relaxed state brought on by constant low level alcohol consumption, this drink sharpened the mind and helped bring forth new ideas and the energy to act on them. The introduction of coffee in the 1600s occurred during the Scientific Revolution and the Age of Reason that led into the Enlightenment and Industrial Revolution of the Eighteenth Century.

While intellectuals, scientists, and philosophers were drawn to the drink and the pleasant consumption environment of the cafe, the leaders of society were less pleased with the resultant intellectual output. Efforts were made to control or ban coffee on the grounds that it was contributing to revolutionary ideas that could change society, and not to the benefit of the powerful. Today we look back on this era as a time of enormous intellectual fervor and societal change that led to the emergence of the modern world. It seems likely that coffee and the intellectual environment of the coffee house played at least some role in this process. It may even have had a role in the American Revolution following the Boston Tea Party.  After the tea was dumped in the harbor, coffee may have served as a welcome replacement.

Like the Andean people who have chewed coca leaves for hundreds of years in order to gain stamina and energy to work in the thin mountain air, the workers of the early modern era learned that coffee could help increase work endurance, give greater energy, and lift mood. This was a hit all way round and after coffee entered western society it never left. It was used extensively during the American Civil War and World War 1 to help soldiers remain alert during the long and arduous campaigns of those wars. Along with alcohol and nicotine, coffee was often included in servicemen’s allotted daily rations. During World War II, coffee had to be rationed for civilians in order to be sure that sufficient supplies were available for the military. Coffee alone did not prove sufficient to maintain alertness during the long and tedious hours of that war, when an attack could suddenly happen without warning. Amphetamines came to supplant caffeine as the stimulant of choice in these situations and were supplied to soldiers.  

Coffee usage in America saw a period of gradual decline as the quality of the product was not always good and in the 1970s soft drinks began to supplement coffee as a daily beverage. Many people will remember instant coffee and percolators and the weak and unappetizing fluids they produced.  These versions of coffee lasted into the 1990s when coffee began to be seen in a new light. The change had actually begun in 1971 when Starbucks was launched in Seattle and quality coffee gradually became significant in the US. It took a couple of decades for good coffee to become broadly available, but by the 1990s people across America were beginning to seek  out and expect quality coffee like that found in European cafes. The shift toward high quality, high cost coffee drinks had begun. Today coffee houses are ubiquitous in America and Europe.

In fact, caffeine, the primary stimulant in coffee and other foods and drinks, is the world’s most consumed psychoactive substance. It is obtained from many sources including coffee, tea, guarana, guayusa (Gage, 2017), energy drinks, caffeine pills, chewing gum, chocolate, alcoholic beverages such as Irish coffee and Kahlua, nutrition supplements, over the counter pain medications, and prescription medicines. Little wonder it is so heavily consumed.

Since most Americans are consuming quite a bit of caffeine - even if they don’t know it because it is in so many foods, drinks, and medicines - what can we say about its effects on sleep? Research findings offer some answers. Consumption of caffeine prior to bedtime increases the time it takes to fall asleep and reduces the overall amount of sleep during the night (see Roehrs & Roth, 2011). Caffeine can reduce sleep efficiency (the percentage of time in bed asleep) from around 90% to 74%, nearly comparable to other, more powerful, stimulants like Ritalin. There are also data indicating that deep sleep is reduced by consumption of caffeine while REM sleep is not. This could be significant as deep sleep is the most restorative portion of sleep and loss of it could result in increased fatigue. We also know that discontinuing use of caffeine after a long period of use results in increased sleepiness and fatigue.

Even if consumed long before bedtime, caffeine can still disrupt sleep (Drake, Roehrs, Shambroom, & Roth, 2013). Of note, caffeine causes sleep fragmentation with multiple brief awakenings. Users often do not associate these awakenings with their use of caffeine, as they are subtler and less obvious than the prolonged wakefulness before falling asleep that people usually expect from caffeine. Sleep fragmentation, rather than initial wakefulness, was especially prominent when caffeine was consumed earlier in the day rather than near bedtime. As a result, people do not make the connection between their caffeine intake earlier in the day and the poor quality of their sleep many hours later. Most people probably do not realize the degree to which caffeine can disrupt sleep even six hours after consumption. The findings of Drake et al (2013) support the long standing sleep hygiene recommendation to stop caffeine intake no later than 2:00 PM.

In future blogs I will focus on the ways in which caffeine affects the brain, body, and mind. I’ll be looking at aspects of its use such as in conjunction with napping to restore mental function as well as caffeine’s impact on exercise and physical health. In the meantime, I hope you have a chance to wake up and smell the coffee. But stop drinking it after lunch.

Drake, C., Roehrs, T., Shambroom, J., & Roth, T. (2013). Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed. Journal of Clinical Sleep Medicine : JCSM : Official Publication of the American Academy of Sleep Medicine, 9(11), 1195–1200.

Gage, T. (2017). Fully alive: Using the lessons of the Amazon to live your mission in business and life. New York: Simon & Schuster, Inc.

Roehrs, T. & Roth, T. (2011). Medication and substance abuse, in Kryger, M. H., Roth, T. & Dement, W. C. (Eds). (2011). Principles and Practice of Sleep Medicine 5th Edition. St. Louis, Missouri: Elsevier Saunders.

"Yin and Yang" by Klem - This vector image was created with Inkscape by Klem, and then manually edited by Mnmazur.. Licensed under Public Domain via Wikimedia Commons -
Source: "Yin and Yang" by Klem - This vector image was created with Inkscape by Klem, and then manually edited by Mnmazur.. Licensed under Public Domain via Wikimedia Commons -