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Caffeine and Sleep

Please note this information is not medical advice, and for advice on your specific needs you should always consult your medical practitioner.

You might reach for a cup of coffee to keep you awake and alert through the day, but is this cup of coffee preventing you from getting a quality sleep at night?

Importance of sleep

Sleep is an essential part of human life. It helps our bodies to repair and boosts mental and physical health. Sleep deficiencies are associated with several health complications such as heart diseases, diabetes, high blood pressure, kidney malfunction and mental health problems [1][2]. Chronic sleep deficiency can also shorten your lifespan [2].

Caffeine and sleep

Many people use caffeine, mainly in the form of coffee, to keep them awake and more alert. Caffeine in coffee acts as a neuro-stimulant and promotes wakefulness. While it can be beneficial in some situations, caffeine can also interfere with the nighttime sleep by increasing the time it takes to fall asleep, decreasing sleep duration and reducing sleep efficiency [3]–[5]. Caffeine is also known to decrease the time spent in deep sleep [3].

One study conducted with adult Australian caffeine users confirmed that higher caffeine consumption leads to decreased bedtime and poor sleep quality [6]. Studies have also found that sleep disturbances result in daytime tiredness that leads to increased coffee consumption in the mornings [7]. This in turn causes nighttime sleep deficiency and this creates a recurring “Coffee cycle” [7].

How does caffeine interrupt sleep?

Adenosine is a neuromodulator that promotes drowsiness. When adenosine binds to the adenosine receptors on nerve cells, it curbs the activity of nerve cells, thus inducing sleepiness. Caffeine has a structure similar to the adenosine molecules and therefore can bind with the adenosine receptors. When adenosine receptors are occupied by caffeine, adenosine can’t bind with its receptors. As a result, the neuron activity is not suppressed and sleep is not induced. [8]–[11]

Another compound that regulates sleep is the neurohormone melatonin. Melatonin controls the sleep-wake cycles [10]. When the amount of melatonin increases, we feel drowsy [10]. Caffeine consumption has found to decrease the secretion of melatonin and thus delay sleep [12].

Why you shouldn’t consume caffeine near bedtime

Caffeine has a half-life of 3-7 hours, meaning half of the caffeine consumed still lingers in your system after 7 hours [13]. If you consume caffeinated foods or beverages near bedtime, there is a chance that it can prevent you from getting a quality sleep at night.

This fact is actually backed up by scientific research [14]–[16]. One study concluded that consuming even one cup of caffeinated coffee at dinner significantly affected the quality of sleep, increased the time taken to fall asleep and increased the number of nighttime awakenings [15]. This study found that drinking decaffeinated coffee did not impair the sleep of the study subjects [15]. Another study found that consuming caffeine even 6 hours before bedtime can substantially disrupt sleep [14].

Decaf vs regular coffee

A standard 240 ml cup of coffee usually contains around 130 mg of caffeine while a decaffeinated coffee of the same size only contains 5mg of caffeine [15]. Therefore, the decaf version is less likely to interrupt with your sleep.

Also keep in mind that it’s not only coffee that contains caffeine. Caffeine is there in tea, energy drinks as well as in chocolates. It can also be contained in some medications such as headache medicine.

If you have difficulty falling asleep or staying asleep at night, it’s a good idea to watch your daytime caffeine intake.


References

[1] “Sleep Deprivation and Deficiency | NHLBI, NIH.” https://www.nhlbi.nih.gov/health-topics/sleep-deprivation-and-deficiency (accessed May 02, 2021).

[2] F. S. Luyster, P. J. Strollo, P. C. Zee, and J. K. Walsh, “Sleep: A Health Imperative,” Sleep, vol. 35, no. 6, pp. 727–734, Jun. 2012, doi: 10.5665/sleep.1846. https://academic.oup.com/sleep/article/35/6/727/2709360?login=true

[3] I. Clark and H. P. Landolt, “Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials,” Sleep Med. Rev., vol. 31, no. November, pp. 70–78, 2017, doi: 10.1016/j.smrv.2016.01.006. https://www.sciencedirect.com/science/article/abs/pii/S1087079216000150

[4] B. J. Distelberg, A. Staack, K. D. Elsen, and J. Sabaté, “The Effect of Coffee and Caffeine on Mood, Sleep, and Health-Related Quality of Life,” J. Caffeine Res., vol. 7, no. 2, pp. 59–70, 2017, doi: 10.1089/jcr.2016.0023. https://www.liebertpub.com/doi/abs/10.1089/jcr.2016.0023

[5] T. Roehrs and T. Roth, “Caffeine: Sleep and daytime sleepiness,” Sleep Medicine Reviews, vol. 12, no. 2. W.B. Saunders, pp. 153–162, Apr. 01, 2008, doi: 10.1016/j.smrv.2007.07.004. https://www.sciencedirect.com/science/article/abs/pii/S1087079207000937

[6] E. J. Watson, A. M. Coates, M. Kohler, and S. Banks, “Caffeine consumption and sleep quality in Australian adults,” Nutrients, vol. 8, no. 8, Aug. 2016, doi: 10.3390/nu8080479. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997392/

[7] F. O’callaghan, O. Muurlink, and N. Reid, “Effects of caffeine on sleep quality and daytime functioning,” Risk Manag. Healthc. Policy, vol. 11, pp. 263–271, 2018, doi: 10.2147/RMHP.S156404. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6292246/

[8] J. E. James and M. A. Keane, “Caffeine, sleep and wakefulness: Implications of new understanding about withdrawal reversal,” Hum. Psychopharmacol., vol. 22, no. 8, pp. 549–558, 2007, doi: 10.1002/hup.881. https://onlinelibrary.wiley.com/doi/abs/10.1002/hup.881

[9] T. Bjorness and R. Greene, “Adenosine and Sleep,” Curr. Neuropharmacol., vol. 7, no. 3, pp. 238–245, Sep. 2009, doi: 10.2174/157015909789152182. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2769007/

[10] “The Science of Sleep - American Chemical Society.” https://www.acs.org/content/acs/en/education/resources/highschool/chemmatters/past-issues/archive-2014-2015/the-science-of-sleep.html (accessed May 02, 2021).

[11] S. C. Holst and H. P. Landolt, “Sleep Homeostasis, Metabolism, and Adenosine,” Current Sleep Medicine Reports, vol. 1, no. 1. Springer International Publishing, pp. 27–37, Mar. 01, 2015, doi: 10.1007/s40675-014-0007-3. https://link.springer.com/content/pdf/10.1007/s40675-014-0007-3.pdf

[12] L. Shilo et al., “The effects of coffee consumption on sleep and melatonin secretion,” Sleep Med., vol. 3, no. 3, pp. 271–273, 2002, doi: 10.1016/S1389-9457(02)00015-1. https://www.sciencedirect.com/science/article/abs/pii/S1389945702000151

[13] J. L. Temple, C. Bernard, S. E. Lipshultz, J. D. Czachor, J. A. Westphal, and M. A. Mestre, “The Safety of Ingested Caffeine: A Comprehensive Review,” Front. Psychiatry, vol. 8, no. May, pp. 1–19, 2017, doi: 10.3389/fpsyt.2017.00080. https://www.frontiersin.org/articles/10.3389/fpsyt.2017.00080/full

[14] C. Drake, T. Roehrs, J. Shambroom, and T. Roth, “Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed,” J. Clin. Sleep Med., vol. 9, no. 11, pp. 1195–1200, Nov. 2013, doi: 10.5664/jcsm.3170. https://jcsm.aasm.org/doi/full/10.5664/jcsm.3170

[15] C. LLORET-LINARES et al., “Does a single cup of coffee at dinner alter the sleep? A controlled cross-over randomised trial in real-life conditions,” Nutr. Diet., vol. 69, no. 4, pp. 250–255, Dec. 2012, doi: 10.1111/j.1747-0080.2012.01601.x. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1747-0080.2012.01601.x

[16] C. DRAPEAU, I. HAMEL-HEBERT, R. ROBILLARD, B. SELMAOUI, D. FILIPINI, and J. CARRIER, “Challenging sleep in aging: the effects of 200 mg of caffeine during the evening in young and middle-aged moderate caffeine consumers,” J. Sleep Res., vol. 15, no. 2, pp. 133–141, Jun. 2006, doi: 10.1111/j.1365-2869.2006.00518.x. https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2869.2006.00518.x