What Is A Caffeine Crash? Plus, 4 MD Tips To Prevent It From Happening

Recently, one of my clients mentioned he had been feeling noticeably tired and irritable, 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 increased levels of stress in his personal life. While I agreed that likely played a part, 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 tiredness due to suboptimal sleep. Sure, the coffee was powering the early part of his day. But the side effects he was experiencing in the midafternoon were what we call a caffeine crash.

Most Americans partake in some form of caffeine every day. That might include things like coffee, cacao beans, kola nuts, tea, yerba mate, sodas, and energy drinks. Some people take supplements that contain caffeine in capsules, tablets, or powders.

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 naturally stimulating compound, 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 slightly. For most people, these physiological changes are temporary.  

But for some people, caffeine can create undesirable effects. Mild side effects of caffeine include feelings of anxiousness, restlessness, irritability, agitation, gut upset, and subpar sleep.

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 livers metabolize caffeine: high, regular, and low metabolizers. 

For high (aka fast) metabolizers, this enzyme breaks down and helps clear caffeine very quickly. Low 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. The primary way caffeine increases alertness and provides energizing effects is by blocking adenosine from attaching to brain receptors.* One of adenosine's main roles is to build up during the day and slow down brain activity, making you sleepy. 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. This can result in that dreaded caffeine crash sensation (i.e., the infamous afternoon slump).

Just like most things we consume, moderation is key. Caffeine carries potentially adverse effects, depending on how much you consume as well as your personal physiology and thus, sensitivity to caffeine. If you rely on your morning coffee to pull you through the day, you might find its energizing effects tapering off midday. On the other hand, eliminating caffeine cold turkey can create some unpleasant side effects of its own. 

Consider why you rely on caffeine. Is it suboptimal sleep or stress management, or feelings of boredom or hunger? Or is it leveraging the power of this nootropic phytonutrient for cognitive energy, focus, and performance?* Investigating those underlying reasons, along with these strategies, can help eliminate a caffeine crash:

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

Eating foods (i.e., emphasize fibrous vegetables and limit refined sugars) that support your gut also helps to balance blood sugar. As a result, you will have more energy and focus, be able to maintain a healthy body composition, and bolster your immune system.

Perhaps your problem isn't caffeine intake itself, but the form of caffeine that you're consuming. Trading one (or a couple) of your daily cups of coffee for a high-quality focus supplement that promotes sustained energy can help you avoid the afternoon slump.

mbg's focus+ features both instant- and sustained-release caffeine that's 100% plant origin (from whole coffee berry and green coffee bean, respectively), so you can feel stimulating effects right away and throughout the day, minus the crash.* It's all the energy, focus, and attentiveness you want with none of unwanted side effects!*

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. Undesirable side effects kick in about 12 to 24 hours after you stop consuming caffeine. They become most pronounced within one to two days, and can last for up to a week. These include sensitivity to sounds and light, tiredness, gastrointestinal upset, mood changes, and sometimes headache.

To minimize these side effects, I taper my clients off of caffeine. Switching to half-regular and half-decaf, then gradually moving into 100% decaf over the course of three to seven days makes the weaning process more bearable. If side effects appear that are simply too much to handle, I will have the individual add back a small amount of caffeine and slowly continue the taper. The same goes for all caffeine-rich beverages, including sodas.

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 reducing insulin sensitivity and increasing unwanted weight3. I've written about how poor quality sleep can affect gut health, and you're also more prone to suboptimal immune response4 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 that's not set in stone. You should figure out what works best for you individually.

Everyone metabolizes caffeine differently and consumes difference sources of caffeine. That's why people 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 root problems (such as lack of sleep). Once you're mindful of how your body processes caffeine, you can determine the best way to embrace caffeine in your life, while successfully mitigating caffeine crashes.