Caffeine is a stimulant that can keep you alert and energized but can also interfere with your sleep. If you are a caffeine lover, you might wonder how caffeine affects your sleep quality and quantity and how you can enjoy your caffeine fix without compromising your sleep.
In this article, we will answer these questions and give tips to balance your caffeine intake and sleep health.
1. Caffeine makes it harder for you to fall asleep and stay asleep
The most obvious effect of caffeine on sleep is that it can delay your sleep onset and reduce your sleep duration. This happens because caffeine blocks a chemical in your brain called adenosine, making you sleepy as it accumulates throughout the day (Drake et al., 2013).
Caffeine also boosts other chemicals in your brain, such as dopamine and norepinephrine, which make you feel more alert and aroused (Nehlig, 2018)6.
The effects of caffeine can last for several hours after you consume it, depending on how much you drink and how fast your body breaks it down. The average time it takes for your body to get rid of half of the caffeine is about 5 hours, but this can vary from person to person, depending on factors such as age, genetics, liver function, and medication use (Mayo Clinic, 2017)5. Some people may still feel the effects of caffeine up to 12 hours after drinking it (Clark & Landolt, 2017)4.
For example, drinking caffeine too close to bedtime, you may have trouble falling or staying asleep. Research has shown that drinking caffeine even 6 hours before bedtime can reduce your total sleep time by about an hour (Drake et al., 2013)3.
Caffeine can also affect the quality of your sleep, by decreasing the amount of deep sleep and increasing the amount of light sleep and awakenings (Landolt et al., 1995)4.
Suggested Action. To avoid the negative effects of caffeine on your sleep onset and duration, limit your caffeine intake to no more than 400 mg per day, equivalent to about 4 cups of coffee (Mayo Clinic, 2017)5.
Also, avoid drinking caffeine in the afternoon or evening and stick to a regular sleep schedule.
2. Caffeine messes up your biological clock and your sleep cycle
Another way that caffeine affects your sleep is by interfering with your biological clock, which is your internal system that regulates your sleep-wake cycle. External cues, such as light and temperature, and internal cues, such as hormones and neurotransmitters, influence your biological clock.
Caffeine can mess up your biological clock by inhibiting the production of melatonin, a hormone that tells your body to get ready for sleep (Burke et al., 2015)1. Caffeine can also change the genes’ activity in controlling your biological clock (Wright et al., 2015)12. These effects can lead to a shift in your sleep phase, meaning you may feel more alert at night and sleepy in the morning.
The effects of caffeine on your biological clock can vary depending on the time of day that you consume it. For example, drinking caffeine in the morning can help you align your biological clock with the environmental light-dark cycle, improving your alertness and performance during the day (Reid et al., 2012)7.
However, drinking caffeine in the evening can delay your biological clock and make it harder to adjust to a new time zone or a shift work schedule (Burke et al., 2015)1.
Suggested Action. To optimize the effects of caffeine on your biological clock, drink caffeine in the morning or early afternoon, and avoid drinking caffeine in the evening or at night.
Also, expose yourself to natural light during the day and avoid bright light at night, to help your biological clock stay in sync with the environmental cues.
3. Caffeine can affect your sleep quality and quantity indirectly through other factors
Besides the direct effects of caffeine on your sleep, caffeine can also indirectly affect your sleep quality and quantity through other factors, such as your hydration, nutrition, and mood. For example:
- Caffeine can cause dehydration, as it is a diuretic that makes you pee more (Sleep Foundation, 2020)9. Dehydration can make you feel thirsty, dry, and uncomfortable, interfering with sleep.
- Caffeine can affect your nutrition, reducing your appetite, changing your taste perception, and interfering with the absorption of some nutrients, such as calcium and iron (Temple et al., 2017)11. Poor nutrition can affect your energy levels, immune system, and overall health, affecting your sleep (Sleep Foundation, 2020)10.
- Caffeine can affect your mood, as it can trigger anxiety, nervousness, irritability, and jitteriness, especially if you consume too much or are sensitive to it (Temple et al., 2017)11. These negative emotions can make relaxing and falling asleep harder (Sleep Foundation, 2020)8.
Suggested Action. To minimize the indirect effects of caffeine on your sleep, drink plenty of water to stay hydrated, eat a balanced diet to meet your nutritional needs, and limit your caffeine intake to avoid adverse effects on your mood.
Also, practice relaxation techniques, such as meditation, breathing exercises, or yoga, to calm your mind and body before bed.
Conclusion
Caffeine can affect your sleep quality and quantity directly and indirectly. While caffeine can benefit your alertness and performance, it can also interfere with your sleep onset, duration, cycle, and rhythm, as well as your hydration, nutrition, and mood.
To enjoy your caffeine fix without compromising your sleep, follow these tips:
- Limit your caffeine intake to no more than 400 mg per day
- Avoid drinking caffeine in the afternoon or evening
- Stick to a regular sleep schedule
- Drink plenty of water to stay hydrated
- Eat a balanced diet to meet your nutritional needs
- Practice some relaxation techniques before bed
By following these tips, you can balance your caffeine intake and sleep health, and enjoy the best of both worlds.
Sources and References
- Burke, T. M., Markwald, R. R., McHill, A. W., Chinoy, E. D., Snider, J. A., Bessman, S. C., … & Wright, K. P. (2015). Effects of caffeine on the human circadian clock in vivo and in vitro. Science translational medicine, 7(305), 305ra146. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4657156/
- Clark, I., & Landolt, H. P. (2017). Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials. Sleep medicine reviews, 31, 70-78. https://pubmed.ncbi.nlm.nih.gov/26899133/
- 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, 9(11), 1195-1200. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3805807/
- Landolt, H. P., Werth, E., Borbély, A. A., & Dijk, D. J. (1995). Caffeine intake (200 mg) in the morning affects human sleep and EEG power spectra at night. Brain Research, 675(1-2), 67-74. https://pubmed.ncbi.nlm.nih.gov/7796154/
- Mayo Clinic. (2017). Caffeine: How much is too much? Retrieved from https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/caffeine/art-20045678
- Nehlig, A. (2018). Interindividual differences in caffeine metabolism and factors driving caffeine consumption. Pharmacological reviews, 70(2), 384-411. https://pubmed.ncbi.nlm.nih.gov/29514871/
- Reid, K. J., Harker, J., Bala, E., Reynolds, C., Mashayekh, A., Oh, J., … & Zee, P. C. (2012). The relationship between caffeine and coffee consumption and excretion of urinary melatonin metabolite: influence of circadian phase and genotype. Chronobiology International, 29(9), 1316-1322. https://sci-hub.se/10.1155/2012/371248
- Sleep Foundation. (2020). Anxiety and sleep. Retrieved from https://www.sleepfoundation.org/mental-health/anxiety-and-sleep
- Sleep Foundation. (2020). Dehydration and sleep. Retrieved from https://www.sleepfoundation.org/nutrition/dehydration-and-sleep
- Sleep Foundation. (2020). Nutrition and sleep. Retrieved from https://www.sleepfoundation.org/nutrition
- Temple, J. L., Bernard, C., Lipshultz, S. E., Czachor, J. D., Westphal, J. A., & Mestre, M. A. (2017). The safety of ingested caffeine: a comprehensive review. Frontiers in psychiatry, 8, 80. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5445139/
- Wright Jr, K. P., McHill, A. W., Birks, B. R., Griffin, B. R., Rusterholz, T., & Chinoy, E. D. (2014). Entrainment of the human circadian clock to the natural light-dark cycle. Current Biology, 24(16), 1934-1938. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4020279/