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Is caffeine affecting your sleep?

Seattleites love their coffee. According to a coffee culture article in The Daily Beast,we number35 coffee shops for every 100,00 residents, making us the most caffeine-saturatedAmerican city. (Another fun fact: wefrequently 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’rethe 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 ofcaffeine on your sleep (and sleep hygiene), let’s take a look at why you want to drink coffeein the first place.

Most people who consume caffeinated beveragesdo so because they want the “pick me up” of a mild stimulant. Waking up in the morning is hard, so wedrink 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 isgray 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.

A recent studyout 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, thissecond wave ofcoffee may onlybe feedingyour 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 addictionworks:

If you drinkcoffee on the way to work in the morning, your caffeine levels decrease slowlyas 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 headachesandirritability. Any oneof these can negativelyaffect 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 yourwithdrawal symptoms by giving your body the drug it craves.

Without the withdrawal symptoms, you perform normally. Unfortunately, this normal performance is temporary. It will vanishagain as the caffeineyou just drank leavesyour system.

Essentially, to drink coffee daily is to get yourself hooked on a drug(yes, the FDA considers caffeineadrug). 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 drinkingcaffeine?

In pharmacology terms, caffeine is a drug astimulant affecting the central nervous system. Like all drugs, it has a half-life, which isthe 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 coffeeas 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:

  • age
  • body weight
  • medications you’re taking
  • liver health
  • if you’re pregnant
  • if you’re a smoker

For example, pregnant women may experiencea caffeine half-life of 15 hours meaning acup of coffee could stay in a mom-to-be’sbloodstream for 30 hours.

For most of us, thetypical 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 bloodstreamsix 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, youmay feel the impact of this loss whenyou’re trying to cram for midterms or finals. If you’re a professional, a lack of REM sleep cantake its toll by affecting memorization. Try preparing for atalk or presentation when you’re having short-term memory issuesit’s not easy.

Without enough REM sleep, youmay also have problems with daytime cognitive functions: for example, doing simple math, recalling peoples’names, or remembering why you logged onto Facebook thirtyminutes 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. Caffeineworks 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 nighttimewakefulness and shorter REM sleep continues.

What about energy drinks?

Maybe you avoidthe daily Starbucks or Peet’s run in favor ofcaffeinated energy drinks. You know the ones they come insmall aluminum cans or thumb-sized plastic bottles by the convenience store cash register.

Energy drinks are everywhere and they’reconvenient. They’reeasy to grab on the run and stash in a handbag or backpack, which makes them a popular choice for teens and college students. Lots ofyoung peoplerely on energy drinks to help get them through busydays packedwith 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 drinksbe, really? Pretty bad.

  • Energy drinks areloaded up with sugar. Read the labels; a tiny bottle that fits in your hand could have as much sugar and calories as a full can of Coke.
  • The caffeine levels in these drinks can be extreme. Some may contain a modest80 milligrams per serving. Others contain 350, more than a Starbucks grande. A safe level of daily caffeine consumption for an adult is 400 milligrams. A single, high-caffeine energy drink couldbe unsafe for a child or teen, and two such drinks per day could be dangerous for adults. (Source: U.S. News & World Report ).
  • Energy drinks also contain an ingredient called taurine. Taurine and caffeine boosteach other’s effects. The result can beconstricted blood vessels, which may lead to heart abnormalities (like irregular heartbeats or cardiac arrest)and seizures.
  • Less alarming, but still serious, effects of too much caffeine includeheadaches, dehydration, andchest pain.

If you’re an adult and you must drink coffee or energy drinks, take care to read labels and limit your intake to 400 milligramsper 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

Nowyou’re aware of how caffeine is messing up your system. To get the best possiblequality 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 shouldquit caffeine altogether. A clean system means no half-life and no withdrawal symptoms.

If you can’tquit, the next best thing is to stop consumingcaffeine 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”) isan effective pick-me-up during that time of day when your body hits a natural slump.

Acup of coffee consumed quickly, followed by a15 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 Napso you awaken right before you get thatcaffeine surge.

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



Johns Hopkins Medical School

News: Medical/Life Sciences

The Daily Beast

U.S. News & World Report

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