If you’ve overdone it on coffee and you’re feeling jittery, anxious, or like your heart is beating too fast, the most important thing to know is that caffeine has a half-life of about five hours in most people. That means half the caffeine in your system right now will be gone in roughly five hours, and you’ll start feeling noticeably better well before that. In the meantime, there are several things you can do to take the edge off.
Why You Feel This Way
Caffeine works by blocking receptors in your brain that normally respond to a calming chemical called adenosine. Adenosine is what makes you feel sleepy and relaxed as the day goes on. When caffeine sits in those receptors instead, your brain essentially loses its braking system. The result is heightened alertness, but when you’ve had too much, that tips over into restlessness, a racing heart, anxiety, and sometimes trembling hands.
Caffeine also indirectly increases dopamine activity in the brain, which is why it feels rewarding in moderate doses but overstimulating in large ones. At the same time, it triggers your body’s stress response, releasing adrenaline and raising your heart rate and blood pressure. All of this is temporary, but it can feel alarming when you’re in the thick of it.
Stop Drinking Caffeine Immediately
This sounds obvious, but it’s worth saying: put down the coffee, energy drink, or tea. Also watch for hidden caffeine in things like chocolate, certain sodas, and pre-workout supplements. Your body needs time to clear what’s already in your system, and adding more will only extend the timeline. The FDA considers 400 milligrams a day (roughly two to three 12-ounce cups of brewed coffee) to be the upper end of what most adults tolerate well. If you’ve blown past that, the priority is stopping the intake.
Drink Water, and Drink Plenty of It
Staying hydrated does more than just make you feel better. Research on caffeine clearance in humans found a statistically significant relationship between urine flow rate and how quickly the kidneys clear caffeine from the body. In plain terms, the more hydrated you are and the more you urinate, the faster your body can flush caffeine out. This won’t cut the timeline in half, but it meaningfully supports the process.
Caffeine is also a mild diuretic, meaning it makes you pee more, which can leave you slightly dehydrated and make symptoms like headache and dizziness worse. Sipping water steadily over the next few hours helps counteract that cycle. If you’re also feeling nauseous, small frequent sips work better than gulping a full glass at once.
Eat Something Substantial
If you drank all that coffee on an empty stomach, eating a meal or a solid snack can help. Food won’t pull caffeine out of your bloodstream, but it will stabilize your blood sugar, which caffeine can disrupt, and it can settle your stomach if the acid is bothering you. Go for something with protein, healthy fats, and complex carbohydrates: a banana with peanut butter, toast with eggs, oatmeal, or a handful of nuts. These foods digest slowly and provide steady energy instead of adding to the spike-and-crash feeling.
Foods rich in magnesium and potassium, like bananas, avocados, spinach, and sweet potatoes, are particularly worth reaching for. Caffeine increases calcium activity inside your heart and muscle cells, which contributes to that pounding-heart sensation. Magnesium and potassium help regulate that electrical activity and can ease the feeling of palpitations.
Use Breathing Techniques to Calm Your Nervous System
When caffeine has your fight-or-flight response cranked up, slow diaphragmatic breathing is one of the fastest ways to push back. Breathing deeply from your belly (not shallow chest breaths) activates the vagus nerve, which acts as the body’s built-in brake pedal for stress. It slows your heart rate, lowers your blood pressure, and signals your nervous system that you’re safe.
Try this: breathe in slowly through your nose for four counts, hold for four counts, then exhale through your mouth for six to eight counts. The key is making the exhale longer than the inhale. Do this for two to five minutes and you’ll likely notice a real difference. Gentle movement like stretching or a slow walk can also help reset your heart and breathing patterns. Avoid intense exercise, though, as it will raise your heart rate further and may make the jittery feeling worse.
Try L-Theanine if You Have It
L-theanine is an amino acid found naturally in green tea, and it’s one of the few supplements with solid evidence for taking the edge off caffeine. A study published in Nutritional Neuroscience found that L-theanine combined with caffeine significantly improved focus and alertness while reducing the scattered, anxious feeling that caffeine alone can produce. The study used about 97 milligrams of L-theanine, which is roughly what you’d find in a single supplement capsule (most are sold in 100 or 200 mg doses).
If you don’t have L-theanine capsules on hand, drinking a cup of green tea might seem counterintuitive since it contains some caffeine, but the amount is small (around 25 to 50 mg) and comes packaged with natural L-theanine. If you’re already well over your caffeine limit, skip the tea and just use a supplement if you have one available.
What the Recovery Timeline Looks Like
The average caffeine half-life is five hours, but individual variation is wide, ranging from 1.5 to 9.5 hours. Factors that slow clearance include pregnancy (caffeine half-life can double or triple), oral contraceptives, liver conditions, and certain medications. Factors that speed it up include regular physical activity and being a habitual coffee drinker, since your liver becomes more efficient at processing it over time.
Here’s what that means in practice. If you drank 600 mg of caffeine (roughly four cups of coffee) at 9 a.m., by 2 p.m. you’d still have about 300 mg circulating. By 7 p.m., you’d be down to about 150 mg, which is roughly one cup’s worth. Most people feel noticeably better within two to three hours as levels start to drop, even before the caffeine is fully cleared. The worst of the jitters and anxiety typically fades first, while sleep disruption can linger into the evening.
Symptoms That Need Medical Attention
For most people, drinking too much coffee produces uncomfortable but harmless symptoms that resolve on their own. However, genuine caffeine toxicity is a medical emergency. Get help right away if you experience confusion or hallucinations, seizures, or a severely irregular heartbeat (not just a fast one, but one that feels chaotic or skipping). These symptoms are rare from drinking brewed coffee alone and are more commonly associated with caffeine pills, powders, or energy drinks consumed in large quantities. In severe cases, caffeine overdose can be fatal due to seizures or cardiac arrhythmia.
If you’re unsure whether your symptoms are serious, calling Poison Control (1-800-222-1222 in the U.S.) is a fast way to get guidance specific to how much you consumed and what you’re feeling.
Preventing It Next Time
If this happens to you regularly, it’s worth tracking your actual caffeine intake for a few days. A standard 12-ounce cup of drip coffee contains roughly 120 to 140 mg of caffeine, but a 16-ounce café drink can contain 300 mg or more, and cold brew often runs higher than hot coffee. Many people discover they’re consuming far more than they realized once they add it up. Keeping your daily total under 400 mg, and spacing your cups at least two to three hours apart rather than stacking them back to back, makes a significant difference in how your body handles the load.