Does Caffeine Impact Sleep Quality?

Check out this answer from Consensus:

Caffeine consumption generally has a detrimental effect on sleep quality, particularly when consumed in high doses or close to bedtime. While chronic daytime consumption may not severely disrupt sleep architecture in habitual users, abstaining from caffeine can lead to significant improvements in sleep quality. Individual sensitivity to caffeine varies, with older adults and certain genetic profiles being more susceptible to its sleep-disruptive effects.

Caffeine is a widely consumed psychoactive substance known for its stimulating effects, often used to combat sleepiness and enhance alertness. However, its impact on sleep quality has been a subject of extensive research. This synthesis aims to consolidate findings from multiple studies to determine how caffeine consumption affects sleep quality.

Key Insights

• General Impact on Sleep Quality:
  • Caffeine generally prolongs sleep latency, reduces total sleep time and sleep efficiency, and worsens perceived sleep quality. It also reduces slow-wave sleep and increases wakefulness and arousals1 3 4 6 7.
• Dose and Timing Effects:
  • The negative impact on sleep is more pronounced with higher doses and when caffeine is consumed closer to bedtime1 4 6 9.
• Chronic vs. Acute Consumption:
  • Chronic caffeine consumption during the day does not significantly impair nighttime sleep structure or subjective sleep quality in habitual caffeine consumers, although it may reduce EEG power density in the sigma range during non-REM sleep2 4 8.
• Caffeine Abstinence:
  • Abstaining from caffeine can improve sleep quality, with significant improvements in sleep duration and ease of falling asleep5.
• Individual Differences:
  • There are pronounced individual differences in sensitivity to caffeine’s sleep-disruptive effects, influenced by genetic factors and age, with older adults being more sensitive1 7 10.
• Athletic Performance and Sleep:
  • Caffeine intake before evening training sessions impairs sleep quality, including sleep efficiency and ease of falling asleep, but does not significantly affect athletic performance6 9.

Does caffeine impact sleep quality?

John Caldwell has answered Likely

An expert from Coastal Performance Consulting in Psychology, Sleep Research, Pharmacology, Data Science

General effects of caffeine. Caffeine contained in various foods, beverages, and gums or tablets is consumed by 80% of US adults, and generally speaking, doses ranging from 40 mg to approximately 300 mg (the amount found in a single Starbucks™ medium-roast Venti) improve waking alertness, vigilance, attention, and reaction time. The effects of caffeine on memory and higher-order executive functions, such as judgment and decision making, are less consistent, but some studies show improvements there as well. Caffeine doses above 200 mg positively impact aspects of physical performance as well, such as time-to-exhaustion, muscle strength and endurance, and high-intensity sprints typical of team sports (see McLelland, Caldwell, and Lieberman, 2016).

Effects in sleep-deprived people. Caffeine’s positive effects are particularly noticeable in sleep-deprived people where sufficiently large doses (sometimes as high as 600 mg) can temporarily restore degraded performance almost back to well-rested levels. This is why products such as NoDoz (200 mg caffeine), 5-hour Energy (215-240 mg caffeine), and Stay Alert Gum (100 mg caffeine) are likely to be some of the most commonly used interventions for alleviating the symptoms of jet lag and shift-work sleepiness and for promoting alertness in general. Furthermore, caffeine is recommended as the “compound of choice for counteracting cognitive deficits during sustained military operations.

Effects on sleep. Although caffeine provides a number of benefits to sleep-deprived people, according to Chaudhary et al. (2016, page 2) it “may have adverse sleep-related consequences on subsequent nights [once normal sleep opportunities are again possible]. These sleep disruptive effects may be broadly classified as insomnia symptoms and abnormalities of sleep disruption. Nocturnal use of caffeine may lead to increased worrying at night and sleeplessness. Other subjective insomnia symptoms demonstrated after caffeine consumption in healthy subjects have included decreased total sleep time, difficulty falling asleep, increased nocturnal awakenings, and daytime tiredness. Polysomnographic sleep abnormalities seen after caffeine consumption have included increased sleep latency, decreased stages 2 and 4 of Non Rapid Eye Movement (NREM) sleep, sleep fragmentation with brief arousals from sleep, and decreased sleep duration. These sleep related problems may be amplified in those with insomnia.”

The bottom line. In answer to the question “Does caffeine impact sleep quality?” I would say that the impact of caffeine on sleep depends on the timing of caffeine consumption, the dose, and the extent to which someone is already “tolerant” to the effects of caffeine because of chronic use. In addition, some people are just more sensitive to the effects of caffeine than others. Thus, it is somewhat complicated to make a blanket statement regarding the effects of caffeine on sleep that would cover all of the possible situations. However, a study by Drake et al. (2013) found that a 400 mg dose of caffeine (which is a fairly large dose) taken even as much as 6 hours before bedtime had disruptive effects on the sleep of moderate caffeine users. As a result, Drake et al. supported “sleep hygiene recommendations to refrain from substantial caffeine use for a minimum of 6 hours prior to bedtime.” To be on the conservative side, I would agree with this recommendation. If caffeine, particularly more than 100 mg, is taken within 6 hours of bedtime, it will likely degrade both the quantity and quality of sleep, especially in people who normally consume very little caffeine.

References: For additional information, see the following references.

McLellan TM1, Caldwell JA2, Lieberman HR. A review of caffeine’s effects on cognitive, physical and occupational performance. Neuroscience and Biobehavioral Reviews. 2016 Dec;71:294-312. doi: 10.1016/j.neubiorev.2016.09.001. Epub 2016 Sep 6.

Chaudhary NS, Grandner MA, Jackson NJ, Chakravorty S. Caffeine consumption, insomnia, and sleep duration: Results from a nationally representative sample. Nutrition. 2016 Nov-Dec;32(11-12):1193-9. doi: 10.1016/j.nut.2016.04.005. Epub 2016 May 10. PMID: 27377580; PMCID: PMC6230475.

Drake C; Roehrs T; Shambroom J; Roth T. Caffeine effects on sleep taken 0, 3, or 6 hours before going to bed. J Clin Sleep Med 2013;9(11):1195-1200.

Does caffeine impact sleep quality?

Raphael Vallat has answered Near Certain

An expert from University of California, Berkeley in Sleep Research, Neuroscience, Neuroimaging

I don’t think there is a perfect answer since this would be dependent on timing, dose, baseline level of sleepiness, habitual consumption, and individual caffeine sensitivity (among other cofactors). Yet, studies have shown that caffeine intake, as low as 100 mg, does indeed:

1. delay the timing of the body circadian clock
2. reduce sleep efficiency and sleep duration
3. perhaps even more dramatic, decrease the electrical “depth” of sleep (as measured by the spectral power of the delta brain waves during non-REM sleep).

Some of these effects were also observed when caffeine was ingested in the morning, suggesting that the effect of caffeine on the brain and body might be longer than what most people think.

To have a fuller picture, however, it should be noted that caffeine can eliminate some of the alertness deficits caused by sleep inertia, which is this unpleasant feeling of grogginess, reduced ability, and incomplete awakening that you have in the first minutes after awakening. As such, it may be useful in situations and occupations where someone needs to be quickly alert and functioning upon awakening (e.g. medical residency, truck drivers, military…).

References

• Landolt, H. P., Dijk, D. J., Gaus, S. E., & Borbély, A. A. (1995). Caffeine reduces low-frequency delta activity in the human sleep EEG. Neuropsychopharmacology: Official Publication of the American College of Neuropsychopharmacology, 12(3), 229–238.
• 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.
• Burke, T. M., Markwald, R. R., McHill, A. W., Chinoy, E. D., Snider, J. A., Bessman, S. C., … Wright, K. P., Jr. (2015). Effects of caffeine on the human circadian clock in vivo and in vitro. Science Translational Medicine, 7(305), 305ra146.
• Newman, R. A., Kamimori, G. H., Wesensten, N. J., Picchioni, D., & Balkin, T. J. (2013). Caffeine gum minimizes sleep inertia. Perceptual and Motor Skills, 116(1), 280–293.
• Van Dongen, H. P., Price, N. J., Mullington, J. M., Szuba, M. P., Kapoor, S. C., & Dinges, D. F. (2001). Caffeine eliminates psychomotor vigilance deficits from sleep inertia. Sleep, 24(7), 813–819.