What Is A Caffeine Crash? Plus, 3 MD Tips To Prevent It From Happening

Board-Certified Internist By Vincent M. Pedre, M.D.
Board-Certified Internist
Dr. Vincent M. Pedre is a board-certified internist in private practice in New York City since 2004. He serves as medical director of Pedre Integrative Health, president of Dr. Pedre Wellness, and is the author of Happy Gut.
3 Tips To Avoid That Dreaded Caffeine Crash, From An MD

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Recently, one of my clients mentioned he had been feeling extreme fatigue along with irritability, especially in the afternoon. "Around 3 p.m., I get drowsy, and focusing on work feels impossible," he told me during a virtual consultation. The opposite problem occurred at night as he struggled to fall and stay asleep. 

This client believed his problems stemmed from the increased level of stress that most of us are feeling these days. While I agreed, I also identified another culprit: The massive amounts of caffeine he was drinking every morning. Thomas was drinking black coffee to mask underlying issues such as morning fatigue due to poor sleep. Sure, the coffee was powering the early part of his day. But the symptoms he was experiencing in the midafternoon were what we call a caffeine crash.

What is a caffeine crash?

Most Americans partake in some form of caffeine every day. That includes coffee, cacao beans, kola nuts, tea, yerba mate, sodas, and energy drinks. Some people also ingest caffeine in powder or tablets.  

Regardless of its source, caffeine has nearly a 100% bioavailability when consumed orally, meaning that you absorb all of it into the bloodstream. Its effects kick in in about 45 to 60 minutes and can last three to five hours or longer if you are a slow caffeine metabolizer. Food can inhibit caffeine absorption by a little bit. 

A few hours after drinking moderate or high doses of caffeine, many people experience a caffeine crash. Symptoms include dozing off during the day, feeling irritated, and not being able to concentrate—the opposite of the desired effect people are drinking caffeine for.

For some people, a caffeine crash can also feel like a hangover, with symptoms including nausea, headaches, and vomiting.

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Why do caffeine crashes occur?

All bodies are different, and so people respond to caffeine in various ways. That explains why your friend can have two cups of coffee at dinner and still fall asleep by 10 p.m., while your morning roast might keep you wired until bedtime. To understand why caffeine crashes occur, we need to look deeper at how the body metabolizes caffeine.  

As a stimulant, caffeine fires up the central nervous system, allowing you to become more alert and focused. You may have more energy. An increase in adrenaline may raise your heartbeat or blood pressure. For most people, these physiological changes are temporary.  

For some people, caffeine can create uncomfortable symptoms. Mild side effects of caffeine include anxiety, restlessness, irritability, agitation, gut upset, and impaired sleep. More extreme symptoms include disorientation, hallucinations, mental confusion, seizure, erratic heartbeat, and inadequate blood supply to a part of the body (ischemia).

Why do some people experience these things after they consume caffeine while others handle it just fine? When you consume caffeine, a liver enzyme called CYP1A2 breaks it down. The gene that codes this enzyme varies greatly among people. Scientists divide people into three groups, depending on how quickly their liver metabolizes caffeine: high, regular, and low metabolizers. 

For fast metabolizers, this enzyme breaks down and helps clear caffeine very quickly. Slow metabolizers, on the other hand, break down coffee at a much slower pace, so its effects stick around much longer.

Your brain also plays a role in caffeine metabolism. If you're not sleeping well, it can sometimes result in higher levels of an organic compound called adenosine. One of adenosine's roles is to slow down brain activity, making you sleepy. Caffeine blocks adenosine from attaching to brain receptors. Once your body has metabolized that caffeine and its effects wear off, that adenosine floods brain receptors and tells your brain that it's sleepy time, even if it's in the middle of the afternoon. Which can result in that caffeine crash sensation.

How to eliminate a caffeine crash.

Caffeine carries potentially adverse effects, depending on how much you consume as well as your sensitivity to caffeine. If you rely on it to pull you through the day, you might find that tapering off or eliminating it can create miserable caffeine withdrawal symptoms of its own. 

Consider why you rely on caffeine. Is it poor sleep, stress, or feelings of boredom or hunger? Investigating those underlying reasons, along with these strategies, can help eliminate a caffeine crash:

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1. Eat a gut-supporting diet that balances blood sugar levels.

When your blood sugar levels are all over the map, many symptoms of a caffeine crash get amplified. When blood sugar levels spike and crash, you may feel cranky and lethargic, which may cause you to reach for caffeine.

Eating foods that support your gut also helps to balance blood sugar. As a result, you have more energy and focus, you lose weight, you boost the immune system, and you reduce your risk of disease.

2. Gradually taper off caffeine.

If you're tired of having a caffeine crash and want to quit entirely, just be aware that going off caffeine cold turkey can be a monster. The symptoms of caffeine withdrawal usually happen 12 to 24 hours after you stop. They become most pronounced within one to two days and can last for up to a week. These include headaches, severe fatigue, and nausea. To minimize withdrawal symptoms, I taper patients off caffeine. Switching to half-regular and half-decaf, then gradually moving into 100% decaf over the course of three to seven days makes the withdrawal process less painful. If symptoms reappear during withdrawal that are simply too much to bear, I will have a patient add back a small amount of caffeine and slowly continue the taper. The same goes for caffeine-rich sodas.

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3. Set a daily caffeine cutoff time.

Poor sleep ranks high on the reasons people over-rely on caffeine and experience caffeine crashes. Not getting enough sleep can affect nearly everything, including increasing your risk of insulin resistance and obesity. I've written about how poor sleep can harm gut health, and you're also more prone to getting sick when you don't sleep well.

The best way to avoid this issue is to set a daily cutoff point for coffee consumption. For most people, it's best to not continue drinking coffee after noon. But you can also figure out what works best for you individually.

Bottom line.

Everyone metabolizes caffeine differently and therefore may experience varying levels of caffeine crashes. It's important to listen to your body and see how caffeine affects you, as well as note if you're using caffeine to address problems such as lack of sleep. Once you're mindful of how your body processes caffeine, it can help you determine the best way to mitigate caffeine crashes.

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Vincent M. Pedre, M.D.
Vincent M. Pedre, M.D.
Vincent M. Pedre, M.D., medical director of Pedre Integrative Health and president of Dr. Pedre...
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Vincent M. Pedre, M.D.
Vincent M. Pedre, M.D.
Vincent M. Pedre, M.D., medical director of Pedre Integrative Health...
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