Caffeine’s Potential Effects on Sleep and Sleep Apnea
Like alcohol, caffeine is part of American culture and history, but it too can disrupt sleep patterns and in some cases further complicate sleep disorder conditions. As with alcohol, balance and timing are the keys to safe use, but a lot of people don’t recognize the dangers of caffeine. Found in drinks that many Americans drink every day, such as coffee, tea, and soda, caffeine has become so pervasive in American consumer culture that its potential for abuse is often overlooked. Unfortunately, chronic sleep debt and sleep disorders have become equally prevalent, and caffeine is often used in excess to make up for the fatigue we incur over the course of our busy lives. For sleep apnea in particular, caffeine can increase the severity of symptoms if consumed too late at night, but if consumed earlier and in moderation it can actually help with some symptoms such as daytime sleepiness and cognitive functioning. Through moderation and timing, you should be able to enjoy a morning coffee without relying on three or four of them to get you through the day. But healthy living takes discipline. Understanding a little more about caffeine may help you make decisions that can potentially improve your sleep, improve your overall health, and reduce your sleep apnea symptoms.
Caffeine is a central nervous system (CNS) stimulant that is mild in comparison to most other psychoactive substances. Caffeine occurs naturally in over sixty plants, including the beans of coffee plants and the leaves of camellia sinensis, the source of most common teas, but it can also be made synthetically as an additive to foods and medicines. Products made of chocolate also contain caffeine, depending on how much solid cocoa is included. Due to its mild effects, caffeine is legal and unregulated in most of the world. In the U.S., for example, caffeine is not regulated by the Food and Drug Administration, which classifies it as “generally recognized as safe,” or GRAS, meaning that it still must be included in a product’s list of ingredients, but its quantity can be left unspecified. The most widely taken psychoactive drug in the world, caffeine consumption is on the rise. According to Caffeine Toxicity, a report published by StatPearls online, 80 to 90 percent of Americans consume caffeine every day. Most drink coffee in the mornings and afternoons, but some Americans are drinking caffeine later in the day, especially energy drinks, which offer a caffeinated boost in a juice blend or soda drink.
Caffeine can also be found in many over-the-counter products such as appetite suppressants, exercise and dietary supplements, decongestants, bronchodilators, and other stimulants. Caffeine is quickly absorbed by the stomach, and like alcohol, is then metabolized in the liver, taking three to ten hours to pass through the system.
Caffeine content can vary from one product to another, but on average, an 8-oz coffee from Starbucks contains roughly 180 mg of caffeine, making the popular 16-oz cup around 360 mg. A single shot of espresso, which is normally served in a small cup or mixed in an espresso drink such as a latte, contains about 75 mg, but most of these drinks are served with a double-shot included. If you’re wondering why a normal coffee makes you feel more wiry than a double-shot latte, these numbers explain it. A lot of people think of decaffeinated coffee as caffeine free, which is not the case. A 16-oz cup of Starbucks decaf coffee contains up to 30 mg of caffeine. There are, however, some decaf brands that only contain a few milligrams of caffeine per serving. Starbucks coffee is considered slightly stronger than average, but according to Caffeineinformer.com, the numbers at other popular breakfast chains are similar. A medium size, 16-oz coffee at Dunkin Donuts, for example, contains about 300 mg of caffeine, and a large size (20-oz) contains around 430 mg. By comparison, an average cup of black tea contains about 60-70 mg of caffeine, while green tea contains about half that. Energy drinks can vary as well. According to Sleep Health Foundation’s content lists, a can of Red Bull contains 80 mg of caffeine, while Monster brand drinks can have up to 160 mg or more, depending on the size. Soft drinks like Coke and Pepsi contain around 50 mg, and chocolate products will depend on the amount of dark chocolate contained (usually 20-60mg per 200mg serving. Caffeine tablets like NoDoz (Regular strength) contain 100 mg per tablet.
Keep in mind that these are average amounts, and caffeine levels can also vary from one blend to another, even in the same products. One study, conducted at the University of Florida, analyzed the same type of coffee purchased from the same coffee shop for six consecutive days and found caffeine levels ranging from 259 mg to 564 mg. This is because caffeine content depends on the conditions in which beans are grown, harvested, roasted, and prepared. The strength of tea varies in the same way, depending on the leaves used and how long it is brewed. For soft drinks and over-the-counter products, caffeine is an additive and is therefore more uniform in its quantities, but since it’s not a regulated substance, there is no incentive to list the full content on many products.
In America, caffeine intake is primarily from coffee, though tea is popular in some households. Coffee makes up roughly 54 percent of the caffeine consumption in the world, while tea accounts for 43 percent, with the remaining consumed in soft drinks or as supplements. The average American consumes around 300 mg of caffeine per day, about three times the world average but only half that of countries such as England where tea is more popular.
Caffeine and Sleep Health
If consumed too late in the day, caffeine can affect sleep in a number of ways. According to one study, sleep latency increased an average of 66 minutes, total sleep time decreased an average of two hours, and the amount of wake time more than doubled after consuming caffeine. In addition, a reduction in the amount of non-REM deep sleep (stages 3 and 4) was observed, as well as a corresponding increase in stage 2 intervals. While REM sleep was not as affected in these studies, the shifts to lighter sleep stages suggests an inability to achieve lasting states of deep sleep. As a rule, caffeine’s effects last from four to six hours, but it takes about 24 hours to pass through the body. The majority of studies in this area show the most severe effects within six hours before bedtime and over 200 mg consumed.
Since many people use caffeine habitually, they may not be aware of these effects over time, but caffeine can be mildly addictive, and stopping too quickly can produce withdrawal symptoms. While the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) does not recognize caffeine addiction as a clinical diagnosis, it does mention caffeine use disorder, caffeine-induced sleep disorder and caffeine-induced anxiety disorder as conditions for further study. Caffeinism is also mentioned as a term for intoxication (overstimulation of the CNS) due to excessive consumption of caffeine. In addition, the World Health Organization’s (WHO) International Statistical Classification of Diseases and Related Health Problems (ICD-10) includes caffeine dependence syndrome as a disorder of physical and psychological dependence. As with caffeine use disorder, caffeine dependence syndrome is characterized by “persistent use despite harmful consequences.”
Caffeine withdrawal symptoms include headaches, fatigue, anxiety, difficulty concentrating, depression, irritability, and reduced energy, most of which are common symptoms of sleep apnea. This is why health professionals often recommend a slow wean from caffeine, rather than quitting cold turkey. Another danger is overdose. Caffeine, like any psychoactive substance, can be overused.
A workshop study on the effects of caffeine on the heart concluded that healthy individuals aged 22 to 59 years who consume 50 to 300 mg of caffeine had few negative effects and were likely safe, but larger amounts, particularly for those who are caffeine sensitive, could cause stress on the heart. Caffeine increases production of the stress hormone cortisol, which can lead to health problems such as anxiety, weight gain, and heart disease. Again, these are common comorbid conditions with sleep apnea, and can potentially cause problems beyond insufficient sleep. In rare cases, extremely large doses (10 grams or more) can even be lethal. Recent high-profile deaths involving children and energy drinks have brought more attention to the dangers of drinking too much caffeine too quickly, as well as the role of caffeine sensitivity in some cases. It is for this reason that the FDA cautions consumers about products marketed as energy drinks or energy shots. Any caffeinated product that is consumed quickly or late in the day can have unpredictable results.
Caffeine and Sleep Apnea
Studies have found that sleep disordered breathing is more associated with caffeinated soda than coffee. This is likely due to the amount of soda consumed and the time of day (or night) that people drink it. Given the calorie and sugar content of many of these beverages, lowering one’s soda consumption is probably a good idea regardless of the caffeine content. While sodas generally contain less caffeine than coffee or tea, they can have the same effects when consumed in large amounts.
In moderate amounts, caffeine can actually help people with cognitive or sleepiness issues due to sleep apnea, but when overuse becomes a problem, the effects can last much longer than six hours, and the consequences can be much more extreme.
As the company ResMed points out on their caffeine information page, monitoring caffeine intake is not only a good idea for those with sleep apnea, but for anyone interested in maintaining a healthy sleep schedule. Drinking caffeinated beverages (including soda) earlier in the day, in low quantities, and with a meal, can ensure that it is not affecting your sleep or sleep apnea. If possible, drinking caffeine intermittently, rather than every day, can also make the habit a healthier one. Like a lot of sleep hygiene issues, taking simple steps to better discipline your nightly schedule can improve your sleep considerably, hopefully giving you less need for stimulants to keep you awake in the days that follow.
British Journal of Clinical Pharmacology – https://pubmed.ncbi.nlm.nih.gov/22454948/
Caffeine in Food and Dietary Supplements: Examining Safety: Workshop Summary – https://www.ncbi.nlm.nih.gov/books/NBK202224/
Caffeineinformer.com – https://www.caffeineinformer.com/
Caffeine – StatPearls Publishing – https://pubmed.ncbi.nlm.nih.gov/30137774/
Caffeine Toxicity – https://www.ncbi.nlm.nih.gov/books/NBK532910/
Caffeine Withdrawal – StatPearls Publishing – https://www.ncbi.nlm.nih.gov/books/NBK430790/
Current Neuropharmacology – http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923369/
DSM.psychiatryonline.org – https://dsm.psychiatryonline.org/doi/book/10.1176/appi.books.9780890425596
Food and Chemical Toxicity – https://pubmed.ncbi.nlm.nih.gov/27288929/
ICD10.WHO.int – https://icd.who.int/browse10/2019/en
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Journal of Clinical Sleep Medicine – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3805807/
Sleepeducation.org – http://sleepeducation.org/news/2013/08/01/sleep-and-caffeine