Caffeine and Sleep: Does Caffeine Affect Sleep?

By: SleepScore Labs  |  February 10th, 2017

Every morning, you walk downstairs and head for that glistening coffee pot to make a steaming hot cup of joe. However good that first cup of morning coffee tastes, the feeling that comes from drinking coffee can be even more enticing. Caffeine is a stimulant with powerful physical and mental effects. To maintain healthy sleep, it’s important to understand how caffeine and other stimulants affect the body, and how to manage their consumption to avoid sleep problems.

Caffeine and Sleep: How Does Caffeine Affect Sleep

Caffeine stimulates your body’s central nervous system, increasing alertness and reducing fatigue. Once ingested, caffeine takes effect within 15 to 20 minutes, and half of that caffeine can remain in your system for can last for six or more hours. This is what experts describe as caffeine’s half-life, and it is not a fixed figure. It is the amount of time it takes caffeine to work its way out of your system. This can vary from four to six hours, or more, but seems to average around 5.7 hours.

How would that look in real time? As one expert warns, “if you consume 200mg of caffeine at mid-day, you would still have 100mg in you at around 5.45pm.” This starts to explain just how and why coffee can impair healthy sleep.

What Does Caffeine Do to your Body?

It’s important to be aware of how caffeine affects your body. For instance, a mid-afternoon cup of coffee may interfere with your ability to fall asleep many hours later. Your individual sleep-wake routine also will play a role in the timing of your caffeine consumption. If you’re an early-to-bed person, a 3 PM cup of coffee may upset your normal sleep regimen. To avoid nightly sleep disruptions due to caffeine, work back 10 hours from bedtime to find your caffeine cut-off time.

Caffeine also stimulates the production of adrenaline, an alertness-boosting hormone that is linked to your body’s fight or flight response. An increase in adrenaline raises your heart rate, increases your breathing and brings on a state of increased vigilance and alertness. Caffeine also blocks the effectiveness of adenosine, a chemical that helps to bring on drowsiness and to regulate your sleep-wake cycles. Additionally, caffeine alters sleep architecture, the overall nightly distribution of sleep among the five different sleep stages. Over-caffeinating can reduce time spent in deep sleep, the phase that is critical for physical and mental rejuvenation.

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What Steps Can You Take?

Moderation is definitely the key to kicking your sleep deprivation that’s caused by drinking too much caffeine. That morning cup of coffee is fine, so long as you’re not having trouble sleeping at night. Many people can manage moderate caffeine consumption early in the day without compromising sleep. A general guideline is to curtail caffeine consumption by 2 PM.

Another great strategy is to monitor how much caffeine you’re actually drinking each day. Start the day with the most highly caffeinated beverage, and gradually taper down from there. Switch to a half-regular, half-decaf cup of coffee, or to tea, before forgoing caffeine altogether for the remainder of the day. It’s also important to remember the amount of caffeine in popular drinks can vary widely. An 8-ounce cup of coffee contains approximately 100 milligrams or more of caffeine. A latte can typically have anywhere from 60 -175 mg of caffeine, while a single ounce espresso may have between 47-75 mg. Cola drinks usually have between 25-45 mg of caffeine, while an 8-ounce cup of green tea contains 24-45 mg of caffeine.

If you decide to give up caffeine altogether, try eliminating it gradually. Giving up caffeine abruptly can lead to fatigue and sluggishness, and may cause headaches. These effects are short-term and won’t have any lasting consequences to your overall performance. Nevertheless, it can be easier and less disruptive to gradually taper down your caffeine consumption.

Other Stimulants that Cause Sleep Issues

Caffeine isn’t the only stimulant that can pose problems to sleep. Sugar and nicotine are two other common stimulants associated with sleep difficulties. Consuming too much sugar and eating high-sugar foods too close to bedtime can interfere with sleep. High-sugar foods cause blood sugar levels to fluctuate sharply. During the day, these fluctuations can lead to fatigue, which can cause sleep problems at night.

Nicotine stimulates adrenaline, elevating heart rate and breathing. Smoking or chewing tobacco near bedtime can make it more difficult to fall asleep and can reduce time spent in REM sleep. It can also irritate and inflame the tissues of the nose and throat, which can lead to snoring affecting your sleep quality.

Moderating consumption of caffeine and other stimulants is an essential part of a strong daily sleep routine and a long-term plan for sleep health.

“Caffeine Effects on Sleep Taken 0, 3, or 6 Hours before Going to Bed”. Journal of Clinical Sleep Medicine.
“Caffeine and Sleep”. National Sleep Foundation.
“Effect of Caffeine on Sleep”. US National Library of Medicine, National Institutes of Health.
“Men Who Eat a High-Fat Diet Have Poorer Sleep”. American Sleep Association.
“Effects of Nicotine on Sleep during Consumption, Withdrawal and Replacement Therapy”. US National Library of Medicine, National Institutes of Health.

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