Is caffeine affecting your sleep?

 

 

Seattleites love their coffee. According to a coffee culture article in The Daily Beast, we number 35 coffee shops for every 100,00 residents, making us the most caffeine-saturated American city. (Another fun fact: we frequently rank as having the most bookstores per capita, too.) At $36 per month, our average personal monthly coffee budget is also one of the highest in the nation.

We're the proud home of Starbucks since 1971, as well as the city of origin for other successful chains like Tully's, Seattle's Best Coffee, and Stumptown. Our coffee culture has had a major influence on how coffee is purchased, prepared, presented, and enjoyed across the U.S. and internationally.

Coffee is a huge part of Seattle life, where it's both a favorite drink and a major industry. But have you ever stopped to think what drinking all this java is doing to your sleep?

 

Caffeine, sleep, and wakefulness

Before considering the effects of caffeine on your sleep (and sleep hygiene), let's take a look at why you want to drink coffee in the first place.

Most people who consume caffeinated beverages do so because they want the "pick me up" of a mild stimulant. Waking up in the morning is hard, so we drink coffee or tea after waking to feel more alert.

If you live in Seattle, let's face it — afternoons can be almost as hard as mornings on days when the sky is gray and overcast. Coffee is a comforting, warm drink that has the side benefit of making us more wakeful, alive, and energetic. Right?

Not so fast.

recent study out of Johns Hopkins Medical School found that the mental boost we perceive when we drink coffee may not be the "level up" we think it is. Sure, a cup or two (or three or four) can improve memory, attention span, and how well we perform cognitive tasks (like driving, reading, or calculating a lunch tip). But according to researchers, this short-term increase in performance may not be the result of caffeine actually enhancing your abilities.

Rather, this second wave of coffee may only be feeding your caffeine withdrawal — restoring you to "normal" for a short amount of time instead of making you "better than normal." 

 

"My precious!" (one sign you might be addicted to coffee)

How caffeine addiction works:

If you drink coffee on the way to work in the morning, your caffeine levels decrease slowly as the day wears on. As the caffeine works its way out of your system, you begin to experience caffeine withdrawal symptoms: sleepiness, lack of motivation, and maybe even headaches and irritability. Any one of these can negatively affect your school or work performance.

To address these issues, you may drink more coffee in the afternoon. A few minutes later, you feel your attention span and alertness picking up. You feel you've given yourself a boost — but this boost is artificial. You haven't actually improved your abilities; you've simply stopped your withdrawal symptoms by giving your body the drug it craves.

Without the withdrawal symptoms, you perform normally. Unfortunately, this normal performance is temporary. It will vanish again as the caffeine you just drank leaves your system. 

Essentially, to drink coffee daily is to get yourself hooked on a drug (yes, the FDA considers caffeine a drug). Like any stimulant drug, you feel pretty good when you're on it, but when you're off it, you may have trouble functioning at your peak abilities.

Why do you have to keep drinking caffeine?

In pharmacology terms, caffeine is a drug — a stimulant affecting the central nervous system. Like all drugs, it has a half-life, which is the time it takes for half the drug to leave your body. And like most drugs, it also has withdrawal symptoms. To stop the withdrawal, you drink more coffee as the drug levels decrease in your system, and the cycle continues.

How long does it take for caffeine to reach its half-life? That number varies from person to person. Your half-life may be longer or shorter depending on:

For example, pregnant women may experience a caffeine half-life of 15 hours — meaning a cup of coffee could stay in a mom-to-be's bloodstream for 30 hours.

 

For most of us, the typical half-life is six hours. What this means:

If you drink your first cup of coffee when you get to work at 9:00 A.M., half of that "just got to the office" coffee will still be in your bloodstream six hours later, at 3:00 PM.

It'll take another six hours — until 9:00 P.M. — for you to get to zero. In other words, your morning coffee stays with you nearly all the way to your bedtime. 

How caffeine affects sleep

If you're an all-day consumer of caffeine (and that includes those lunch and dinner diet colas), then the stimulant is in your body 24/7. Science tells us that any caffeine in your bloodstream at all, even small amounts, inhibits your ability to fall asleep

Even if you do fall asleep eventually, the caffeine is working to disrupt your sleep cycles. Caffeine has been shown to reduce the length of your rapid eye movement (REM) sleep, the deepest phase of sleep. That's a problem because REM is when your body consolidates learning and memory and regulates emotions. 

If you don't get enough REM sleep, you may lose your ability to process and consolidate memory. If you're a student, you may feel the impact of this loss when you're trying to cram for midterms or finals. If you're a professional, a lack of REM sleep can take its toll by affecting memorization. Try preparing for a talk or presentation when you're having short-term memory issues — it's not easy.

Without enough REM sleep, you may also have problems with daytime cognitive functions: for example, doing simple math, recalling peoples' names, or remembering why you logged onto Facebook thirty minutes ago.

That's not all. If you're tired, unfocused, and scatterbrained after a night of bad sleep, what's your natural inclination during the day?

To reach for more caffeine to perk you up. Caffeine works in the short term by creating adrenaline surges that "get you through." But every ounce of caffeine you consume during the day is another ounce of caffeine in your bloodstream with a six-hour half-life. The vicious cycle of nighttime wakefulness and shorter REM sleep continues.

What about energy drinks?

Maybe you avoid the daily Starbucks or Peet's run in favor of caffeinated energy drinks. You know the ones — they come in small aluminum cans or thumb-sized plastic bottles by the convenience store cash register. 

Energy drinks are everywhere and they're convenient. They're easy to grab on the run and stash in a handbag or backpack, which makes them a popular choice for teens and college students. Lots of young people rely on energy drinks to help get them through busy days packed with school, sports, studying, and let's face it, partying.

The problem with energy drinks is that they're deceiving. They taste and feel like carbonated beverages.

 

But they're not carbonated beverages; they're drinks with as much caffeine as a Starbucks grande, maybe more.

How bad could energy drinks be, really? Pretty bad.

If you're an adult and you must drink coffee or energy drinks, take care to read labels and limit your intake to 400 milligrams per day. Teens and children should avoid caffeine altogether. If you can't, limit yourself to one milligram per pound of your weight (so if you weigh 120 pounds, that's 120 milligrams).

When to stop consuming caffeine at night

Now you're aware of how caffeine is messing up your system. To get the best possible quality sleep, what time should you stop consuming coffee, energy drinks, black or green tea, or hidden sources of caffeine (like dark chocolate or "non-drowsy" over-the-counter medications)?

For the best possible sleep, of course, you should quit caffeine altogether. A clean system means no half-life and no withdrawal symptoms.

If you can't quit, the next best thing is to stop consuming caffeine at least six hours before bed.

But what about daytime caffeine consumption?

Seattleites, we know how painful "No more coffee!" is for you to hear.

Here's some good news: as long as you stop taking caffeine six or more hours before bed, a moderate amount (250 milligrams or less) during the day can be a useful tool to keep in your toolbox.

For example, some people believe a Coffee Nap (some call it a "Caf Nap") is an effective pick-me-up during that time of day when your body hits a natural slump.

A cup of coffee consumed quickly, followed by a 15 to 20-minute nap, may be more refreshing than taking either the coffee or the nap alone. Since coffee's effects take about half an hour to kick in, you can time your Coffee Nap so you awaken right before you get that caffeine surge.

What do you think? Are you ready to try a Coffee Nap right now?

Sources:

Forbes.com

Johns Hopkins Medical School

News: Medical/Life Sciences

The Daily Beast

U.S. News & World Report

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