The Science of Coffee Naps

In a recent survey looking at office productivity, the majority of 2,000 British employees said they were most productive mid-morning (at 10:22 a.m., to be precise) and felt their first midday dip at 1:27 p.m., followed quickly by another one at 2:06 p.m.

We often feel sluggish in the afternoon due to the natural ebb and flow of our circadian rhythm, the body’s master clock that tells you when to wake up and when to sleep. If you’ve gotten inadequate sleep at night or eaten a carb- or sugar-heavy lunch (causing an energy-depleting drop in blood sugar), that fatigue could feel even greater.

A lot of us counteract the afternoon slump with coffee, the elixir of the weary everywhere. Research shows that low-to-moderate doses of caffeine (50-300 mg, or roughly the amount in one to three 8-oz cups of coffee) are enough to increase alertness, attention, and reaction time.

Others might take a post-lunch snooze, which can improve mental alertness and performance.

But what happens when you combine the two?

Coffee plus a short power nap can make a mightier mid-afternoon pick-me-up than one or the other alone. Some say yes, but timing and technique are crucial. If you’re interested in making the most of both, here’s how to reap the full benefits of a coffee nap.

A coffee nap — also called a nappuccino or caff nap — is exactly what the name implies: a nap that’s timed after drinking a cup of coffee or caffeinated beverage so that you rest your body and awake feeling ready to take on your afternoon.

“A coffee nap requires quickly consuming caffeine and then immediately napping for between

15 to 30 minutes, preferably about 20 minutes,” says Kristina Lenker, Ph.D., a sleep psychologist and an assistant professor in the Department of Psychiatry and Behavioral Health at Penn State.

“Coffee naps work by combining the waking effects of caffeine with the restorative aspects of napping,” explains Lenker. “Caffeine followed by a brief nap has been shown to improve alertness and mental acuity in several studies.”

Caffeine is quickly absorbed into the bloodstream (typically within 45 minutes or so), so by the time you wake from the nap, the stimulating effects of caffeine are kicking in, giving you a double whammy of alertness. The key to a successful coffee nap is deliberately keeping the nap short to prevent you from drifting into harder-to-wake-from deep sleep.

In one study printed in the journal Chronobiology International, participants were given either 200 mg of caffeine or decaffeinated coffee immediately before hunkering down for a 30-minute midafternoon nap. Those who had caffeine experienced better attention and less fatigue 45 minutes after the nap than those who had decaffeinated coffee.

In another study published in Human Kinetics Journals, somewhat sleep-deprived sprinters were split into three groups and given a 20-minute nap, a moderate amount of caffeine, or a nap plus caffeine. Researchers found that athletes in the combined caffeine and nap group performed better in sprinting exercises than those in the other groups.

To understand how caffeine plus a short nap boosts alertness and performance, you have to first understand how each impacts the body alone.

Caffeine blocks a naturally occurring chemical in the body called adenosine, which builds up over the course of the day and produces feelings of sleepiness. Both sleep and caffeine counteract adenosine, but in different ways. While sleep helps rid the body of accumulated adenosine, caffeine blocks it. That’s why, together, caffeine and naps seem to have superior wake-me-up potential than just a cup of coffee or an afternoon siesta alone.

“In order for caffeine to work, the brain first needs to clear receptors of adenosine,” explains Lenker. “This is where a nap comes in to clear the brain of adenosine buildup, allowing caffeine to fit into open receptors.”

Though the concept of a coffee nap may seem simple enough, getting optimal benefits from a coffee nap involves more than hitting the Starbucks drive-thru and then conking out. Sleep specialists advise the following:

Time your nap appropriately. “Coffee naps should be taken in the afternoon, typically after lunch, but not too close to bedtime to disrupt nighttime sleep,” says Lenker. “Because caffeine produces stimulant effects lasting up to six hours, taking a coffee nap too close to bedtime can cause insomnia and other sleep problems.” This is why it’s best to plan your coffee nap when you have at least six to seven hours between the nap and your intended bedtime.

Pick your poison. Not a coffee lover? You can choose another beverage with caffeine, such as an energy drink or tea, but Lenker recommends that you aim to consume about 200 mg of caffeine before the nap.

Drink your caffeinated beverage quickly and then immediately find a quiet, comfortable place to nap. “The coffee is not meant to be slowly enjoyed,” says Dr. Andrew Stiehm, who specializes in sleep medicine and pulmonology at Allina Health. “Rather, drink the coffee quickly and then try to fall asleep. This also means you need a convenient place to sleep, available at the same time you're drinking the coffee.”

Set a timer or alarm for 20 minutes. When naps are kept short (under 30 minutes), you’re less apt to lapse into deep sleep, which is much harder to wake from.

When the alarm goes off, get up. Don’t hit the snooze button. “Sleeping longer than 20 minutes can make you feel groggy,” notes Lenker.

Because caffeine can have different effects on different people, not everyone is a candidate for a coffee nap.

While the Food and Drug Administration (FDA) notes that most healthy adults can safely consume up to 400 mg of caffeine a day (the amount in 4-5 cups of coffee), it’s important to note that some individuals are more sensitive to caffeine’s effects than others. What’s more, some people metabolize it faster or slower than others. The best course of action: Consult your health care provider about what caffeine levels — if any — are safe for you.

“Coffee naps have been shown to be effective in certain situations,” says Lenker. “For sleepy drivers and night shift workers, for example, caffeine combined with a nap can enhance cognitive and physical performance, problem-solving, and mental acuity. However, a variety of conditions may be negatively affected by caffeine, such as pregnancy, chronic headaches, insomnia, anxiety, high blood pressure, and stomach ulcers.” People who want to become pregnant, who are breastfeeding, or who take certain medications, such as some decongestants, should also speak with their health care providers about safe levels of caffeine. Additionally, experts caution against giving children or adolescents caffeine and other stimulants.

If you're experiencing any symptoms of caffeine overload — such as jitteriness, anxiety, or a fast heartbeat, among others — cut back on your caffeine intake and talk to your doctor. And let common sense be your guide. “Listen to your body,” cautions Stiehm. “If [a coffee nap] isn’t working for you, don’t do it.”

Most healthy adults can reap a slew of health benefits from napping, including relaxation, improved mood, greater alertness, and better overall performance. “Napping is normal,” notes Stiehm. “However, being unable to skip your nap may suggest a sleep disorder. This should be evaluated by your health care provider.”

If you can’t get through the day without a nap, be it a caffeine nap or otherwise, your health care provider may suggest that you be evaluated for a condition that can affect your nighttime sleep, such as sleep apnea or restless legs syndrome. They may also examine the medications you take to see if any can cause drowsiness, screen you for a condition like depression, which can make you feel zapped of energy, or suggest dietary or lifestyle modifications, such as eating regularly throughout the day (instead of eating one large meal) and exercising more.

“The nap itself isn't the problem,” points out Stiehm. “It's the ‘why’ behind the nap that is the problem.”