Medically reviewed by
Dacelin St Martin, MD
Triple board-certified in Sleep Medicine,
Internal Medicine, and Pediatrics.
Caffeine & Sleep | Effects Of Caffeine On The Body | When Caffeine Disrupts Sleep |
Overview
There is a big chance that you start your day every morning with a delicious cup of coffee, either self-brewed or from your favorite diner, to get that energy and alertness that makes you feel like you are ready to get your day started.
The chemical compound in coffee responsible for these effects after drinking coffee is caffeine. Caffeine is a natural stimulant frequently used in foods and beverages worldwide.[1]
It naturally occurs in coffee beans, tea leaves, and cocoa beans. Caffeine is also artificially synthesized and utilized as an energizing and stimulating agent in drugs and energy drinks.[1]
However, it is most commonly consumed in beverages, especially coffee, the most consumed caffeinated drink. Although caffeine is generally safe, it can profoundly affect your sleep and body.
This article will highlight the effects of caffeine on your sleep, your body, and how you safely take caffeine so it does not impair your sleep.
Caffeine & Sleep
Caffeine can impact your sleep in many ways. Here are some of the effects caffeine use can have on your sleep. They include:
1) Reduced Quality and Duration of Sleep
Sleep experts have associated caffeine use with delayed sleep onset, reduced sleep duration, and diminished sleep quality.[2]
Caffeine significantly affects the amount of time spent in slow-wave sleep, the deep, peaceful sleep stage that leaves you feeling refreshed and alert the following day.[3]
This physiological effect can lead to you having symptoms of sleep deprivation, like fatigue and difficulty with your memory and learning the following day.
This finding implies that people who use caffeine close to bedtime may find it harder to fall asleep and may not get as much restorative sleep as people who don’t consume caffeine.
2) Caffeine Can Keep You Awake
Caffeine can delay sleep and give you energy throughout your day.
While this might seem like the desired effect, it can harm your sleep, especially when taking caffeine close to your bedtime.
Even though caffeine can help improve your cognitive performance when exhausted, it cannot prevent or reverse the effects of long-term sleep deprivation.[4]
Excessive caffeine use, especially when you are already alert and attentive, may produce heightened arousal, resulting in anxiety, irritability, and dependence on caffeine.[5] Most importantly, it’s no alternative to a peaceful, refreshing night’s sleep.
3) Caffeine Causes or Worsens Insomnia
Sleep experts have observed that consistent caffeine use can cause insomnia.[6] It can also worsen the symptoms of insomnia.
Additionally, studies have shown that caffeinated soda drinks increase the likelihood of developing and worsen the severity of sleep-related breathing disorders like obstructive sleep apnea (OSA).[7]
This link was discovered exclusively with caffeinated soda drinks and not associated with other caffeinated beverages like coffee or tea.[7]
Individuals who suffer from sleep-related breathing disorders may be unaware of this sleep problem and can attribute excessive daytime tiredness to other factors.
If you get exhausted during the day, it may be beneficial to reassess your caffeine intake, mainly if you take caffeinated soda.
4) Caffeine can Increase Sleepiness
Paradoxically, caffeine can sometimes make you sleepy. This effect is less common than the stimulating effect that caffeine gives. Nonetheless, some people feel tired after consuming caffeinated drinks.
A possible explanation for this counterintuitive effect is that the sleep-impairing effects of regular caffeine consumption produce a vicious cycle. [8] As a result of caffeine consumption, sleep loss promotes tiredness the following morning, which causes an increased urge to drink more caffeine to deal with Sleepiness.
Even when caffeine use is increased, sleep deprivation eventually catches up. Subsequent caffeine consumption at this level may not give the typical energizing effect; instead, one might get tired and sleepy.
Effects Of Caffeine On The Body
Caffeine exerts most of its effects by acting on specific receptors in the brain.
When you ingest caffeinated drinks and foods, the caffeine is readily absorbed in your stomach and small intestines. It’s then rapidly dispersed throughout the body after absorption. It passes the blood-brain barrier to get into the brain, where it blocks adenosine receptors.
Adenosine is a sleep-inducing chemical that the brain produces during the day.[9]
Typically, the longer you are awake, the more adenosine accumulates in your brain. The more it accumulates, the sleepier you become. When caffeine inhibits this process, you maintain a state of alertness and wakefulness.
Additionally, caffeine has been shown to disrupt the circadian melatonin rhythm, delaying the onset of sleep when consumed close to bedtime.[11]
The effects of caffeine are felt maximally between 30 and 60 minutes after its consumption.[10] These effects can be felt for as long as 4-6 hours after consumption; however, this time can vary significantly among individuals.[12]
When Caffeine Disrupts Sleep
Sometimes, knowing if caffeine is responsible for your sleep troubles is hard. However, if you have trouble sleeping, you should stay away from caffeine. It might just be what you need to have a better sleep. Here are some signs that can help you know if caffeine is affecting your sleep:
- Difficulty achieving sleep at night, frequent night awakening
- Daytime irritability, anxiety, and headaches
- Excessive daytime sleepiness and fatigue
If you have any of these symptoms, it is high time you stopped caffeine and got the much-needed sleep you deserve.
Tips For Safe Caffeine Use
If you’re a lover of coffee or any other caffeinated drinks but you’re not getting the restful sleep you need, here are some helpful tips to improve your sleep:
1. Avoid taking caffeinated products at least 6 hours from bedtime.[13]
2. Stay away from energy boosters or other products with high caffeine content.
3. Restrict your daily caffeine consumption to less than 400 mg (not more than three cups of coffee).
4. Ensure you don’t exercise or eat too close to bedtime, especially caffeine-containing food like chocolate.
5. Maintain regular sleep and wake time.
References:
- “Caffeine.” MedlinePlus, U.S. National Library of Medicine, 3 Feb. 2022, https://medlineplus.gov/caffeine.html.
- HP;, Clark I;Landolt. “Coffee, Caffeine, and Sleep: A Systematic Review of Epidemiological Studies and Randomized Controlled Trials.” Sleep Medicine Reviews, U.S. National Library of Medicine, https://pubmed.ncbi.nlm.nih.gov/26899133/.
- “Brain Basics: Understanding Sleep.” National Institute of Neurological Disorders and Stroke, U.S. Department of Health and Human Services, https://www.ninds.nih.gov/Disorders/patient-caregiver-education/understanding-sleep.
- McLellan, Tom M., et al. “A Review of Caffeine’s Effects on Cognitive, Physical and Occupational Performance.” Neuroscience & Biobehavioral Reviews, Pergamon, 6 Sept. 2016, https://www.sciencedirect.com/science/article/pii/S0149763416300690?via%3Dihub.
- Urry, Emily, and Hans-Peter Landolt. “Adenosine, Caffeine, and Performance: From Cognitive Neuroscience of Sleep to Sleep Pharmacogenetics.” SpringerLink, Springer Berlin Heidelberg, 1 Jan. 1970, https://link.springer.com/chapter/10.1007/7854_2014_274.
- Chaudhary, Ninad S., et al. “Caffeine Consumption, Insomnia, and Sleep Duration: Results from a Nationally Representative Sample.” Nutrition, Elsevier, 10 May 2016, https://www.sciencedirect.com/science/article/abs/pii/S0899900716300454?via%3Dihub.
- Chaudhary, Ninad S., et al. “Caffeine Consumption, Insomnia, and Sleep Duration: Results from a Nationally Representative Sample.” Nutrition, Elsevier, 10 May 2016, https://www.sciencedirect.com/science/article/abs/pii/S0899900716300454?via%3Dihub.
- Roehrs, Timothy, and Thomas Roth. “Caffeine: Sleep and Daytime Sleepiness.” Sleep Medicine Reviews, W.B. Saunders, 18 Oct. 2007, https://www.sciencedirect.com/science/article/abs/pii/S1087079207000937?via%3Dihub.
- Scharf, Matthew T., et al. “The Energy Hypothesis of Sleep Revisited.” Progress in Neurobiology, Pergamon, 3 Sept. 2008, https://www.sciencedirect.com/science/article/pii/S0301008208000865?via%3Dihub.
- Simone Cappelletti, et al. “Caffeine: Cognitive and Physical Performance Enhancer or Psychoactive Drug?” https://www.eurekaselect.com/article/63919.
- Effects of Caffeine on the Human Circadian … – Science.org. https://www.science.org/doi/10.1126/scitranslmed.aac5125.
- Commissioner, Office of the. “Spilling the Beans: How Much Caffeine Is Too Much?” U.S. Food and Drug Administration, FDA, https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much.
- Drake, Christopher, et al. “Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed.” Journal of Clinical Sleep Medicine, 15 Nov. 2013, https://jcsm.aasm.org/doi/10.5664/jcsm.3170.
