This article is for general information only and does not replace medical advice. If you’re experiencing severe symptoms, contact your healthcare provider or call Poison Control at 1-800-222-1222 (US). Last reviewed May 11, 2026.
You drink your usual coffee. Within twenty minutes the room feels slightly off. A wave of lightheadedness. A pulse you can feel in your throat. Maybe a moment where you have to sit down.
If this has happened to you, you’re not imagining it, and you’re not alone. Coffee-related dizziness is one of the most searched caffeine side effects, and there are clear physiological reasons it happens. Most cases are harmless and resolve in a few hours. A small fraction warrant a doctor’s visit. This guide walks through what’s actually happening in your body, when to worry, and what to do about it.
Why does coffee make you dizzy? Quick answer
Coffee can make you dizzy because caffeine causes blood vessels in your brain to constrict, which reduces blood flow. That effect gets amplified by mild dehydration, blood pressure swings, and how quickly your liver clears caffeine. For most people, the feeling resolves within 2 to 4 hours as caffeine works its way out of your bloodstream.
The rest of this article explains each mechanism, why some people get dizzy from a single cup while others tolerate four, what to do when it happens, and the warning signs that mean you should stop and see a doctor.
What this guide covers
- The four mechanisms behind caffeine dizziness
- Why some people get dizzier than others
- Other symptoms that travel with dizziness
- How long coffee dizziness lasts
- What to do right now
- How to prevent it long term
- When dizziness signals caffeine intoxication
- When to see a doctor
- Special populations: pregnancy, teens, anxiety, hypertension
- Frequently asked questions
- Sources and references
The four mechanisms behind caffeine dizziness
Dizziness from coffee is rarely caused by a single thing. It’s usually a combination of four physiological effects stacking on top of each other.
1. Caffeine narrows the blood vessels in your brain
Caffeine is what’s called an adenosine receptor antagonist, which is the technical way of saying it blocks the brain chemical that normally keeps your blood vessels relaxed. With those receptors blocked, the arteries in your brain constrict, and blood flow drops. Studies measuring cerebral blood flow before and after caffeine routinely report reductions of 20 to 30 percent in healthy adults, with the effect peaking 30 to 60 minutes after you finish your cup (Addicott et al., Human Brain Mapping, 2009).
For most people that drop is well within what your brain handles without you noticing. For people who are sensitive, dehydrated, or already running close to their threshold for dizziness, that 20 to 30 percent drop is enough to produce the lightheaded sensation you might describe after a strong cup.
2. Mild dehydration from caffeine’s diuretic effect
Caffeine has a mild diuretic effect, meaning it makes your kidneys excrete a bit more water. The effect isn’t as dramatic as it’s sometimes made out to be. For habitual coffee drinkers, tolerance largely cancels it out. But if you’re an occasional drinker, or you started the day already under-hydrated, the extra fluid loss can drop your blood volume just enough to amplify the dizziness from cerebral vasoconstriction.
This is why the standard advice to drink a glass of water before your coffee actually has physiological backing. The water doesn’t block caffeine’s effects. It just keeps the dehydration component from stacking on top.
3. Blood pressure swings
Caffeine produces a short, predictable blood pressure spike, typically 5 to 10 mmHg in habitual users (more in non-users), peaking within 30 to 90 minutes and then falling back to baseline. The body’s compensatory response can sometimes overshoot, dropping pressure briefly below normal. People who experience this rebound feel it as lightheadedness, particularly when they stand up quickly. That’s orthostatic dizziness, and it’s a common pattern.
The Mayo Clinic notes that this pressor response, while not dangerous in healthy adults, can be problematic in people with uncontrolled hypertension or those taking blood pressure medications (Mayo Clinic – Caffeine: How much is too much?).
4. The adenosine rebound
Adenosine is the brain chemical that builds up during the day and signals tiredness. Caffeine works by blocking adenosine receptors, which is why coffee fights drowsiness. But adenosine itself doesn’t stop being produced. It accumulates in the background while caffeine occupies the receptor sites. When the caffeine wears off, all that built-up adenosine binds at once, and you can get a brief crash that includes fatigue, headache, and lightheadedness.
This rebound is more noticeable if you drink coffee on an empty stomach (faster absorption, faster wear-off) or if you drink far less than your tolerance level requires.
Why some people get dizzier than others from the same coffee
Two friends order the same espresso. One feels nothing unusual. The other is hanging onto the table. The difference is rarely the coffee. It’s what each person’s body does with the caffeine.
Slow caffeine metabolizers (the CYP1A2 gene)
Caffeine is broken down in your liver by an enzyme called CYP1A2. A common genetic variation, the SNP rs762551, determines how fast your version of that enzyme works. People with the AA genotype are fast metabolizers who clear caffeine in 2 to 3 hours. People with the AC or CC genotypes are slow metabolizers who can take up to four times as long, sometimes 8 to 10 hours, to clear the same dose (Guest et al., Nutrients, 2024).
Slow metabolizers are significantly more likely to report dizziness, jitters, anxiety, and disrupted sleep from a single cup. The 2024 study cited above found that dizziness specifically was reported about two hours after caffeine ingestion in slow-metabolizing groups, but not in fast-metabolizing ones, even at identical doses.
You can test your CYP1A2 genotype through any of the major consumer DNA testing services (23andMe, AncestryDNA’s raw data run through a third-party tool like Promethease, or a dedicated panel through your doctor). If it turns out you’re a slow metabolizer, the practical implication is to keep caffeine to the morning and use smaller doses than the average drinker.
Drinking coffee on an empty stomach
Caffeine on an empty stomach is absorbed in 15 to 30 minutes. With food in the stomach, absorption stretches to 45 to 90 minutes. Faster absorption means a higher peak concentration in your bloodstream, which means a stronger version of every effect described above. Including dizziness.
If your morning routine is coffee on the way to work without breakfast, and you feel dizzy after, eating a small breakfast first is one of the highest-leverage changes you can make. Even a slice of toast or a banana slows absorption enough to flatten the peak.
Pre-existing health conditions
Several conditions amplify caffeine’s effect on dizziness:
- Anxiety disorders. Caffeine and anxiety symptoms overlap (racing heart, jitters, lightheadedness), and caffeine can trigger or worsen panic responses in people predisposed to them.
- Hypertension. Already-elevated blood pressure plus caffeine’s pressor effect creates a wider swing.
- Vestibular disorders like Meniere’s disease, vestibular migraine, or BPPV. These conditions affect inner-ear balance signals, and caffeine can worsen episodes in some sufferers.
- Hypoglycemia. Coffee on an empty stomach with low blood sugar produces dizziness from both directions at once.
- POTS (postural orthostatic tachycardia syndrome) and other autonomic disorders, where any blood pressure swing tends to produce strong symptoms.
Medication interactions
Several common medications either intensify caffeine’s effects or compete for the same metabolic pathway, which raises caffeine levels in your bloodstream:
- Some antibiotics (particularly fluoroquinolones like ciprofloxacin)
- Certain antidepressants (notably fluvoxamine)
- Hormonal contraceptives, which slow caffeine clearance significantly
- Asthma medications (theophylline, which is chemically similar to caffeine)
- Some thyroid medications
If you started a new medication and your usual coffee suddenly produces dizziness, that’s worth flagging. Check the medication’s interaction list or ask your pharmacist whether caffeine sensitivity is a known interaction.
Other symptoms that travel with caffeine dizziness
Caffeine-induced dizziness rarely shows up alone. The companion symptoms can help you identify caffeine as the cause and rule out other possibilities.
Lightheadedness vs. vertigo: they’re not the same
Lightheadedness is the feeling that you might faint. Head feels woozy, vision narrows, you want to sit down. This is what most people mean when they say coffee makes them dizzy. It comes from blood flow and blood pressure changes.
Vertigo is the false sensation of motion. The room is spinning, or you feel like you’re moving when you’re standing still. This usually comes from inner-ear or central nervous system issues, not from caffeine directly. If your “coffee dizziness” is true vertigo, the coffee is more likely a trigger for an underlying vestibular condition than the cause itself, and that’s worth a doctor’s visit.
Common companions to caffeine dizziness
- Heart palpitations, pounding, racing, or skipped beats
- Tingling in fingers or face, usually from the hyperventilation that often comes with the anxiety component
- Mild nausea, since caffeine raises stomach acid and can briefly slow gastric emptying
- Headache, paradoxical, since caffeine is also used to treat headaches
- Hand tremor, fine and fast, particularly visible when you hold something out
- Sweating that feels disconnected from the room temperature
- Brief difficulty concentrating, the so-called “coffee fog” at high doses
If your dizziness comes with most of these, caffeine is the likely cause. If it comes with chest pain, weakness on one side of the body, slurred speech, or confusion, those are not normal caffeine symptoms and need immediate medical attention.
How long does coffee dizziness last?
Most coffee-related dizziness peaks 30 to 60 minutes after the cup and fades within 2 to 4 hours as caffeine clears your bloodstream. Slow metabolizers may feel residual lightheadedness for 6 to 10 hours. Dizziness that persists more than 12 hours after a single cup, or that recurs daily without obvious triggers, is unlikely to be caffeine alone and should be checked by a doctor.
Caffeine has a half-life of about 5 hours in average adults, meaning half of the dose is cleared in 5 hours, three-quarters by 10 hours, and the remainder over the next 12 hours or so. Dizziness duration tracks that curve, with the strongest effects in the first peak window.
What to do right now if coffee made you dizzy
If the lightheadedness has just hit, the priorities are to keep yourself safe and let your body process the caffeine.
- Sit or lie down. Most caffeine dizziness is mild, but the real risk is falls. Get to a chair or the floor before anything else.
- Drink water, slowly. Aim for 8 to 16 oz (240 to 480 ml, roughly 1 to 2 cups) over the next 20 minutes. Slow sipping helps with hydration without triggering nausea.
- Eat something with protein and complex carbs. A handful of nuts, peanut butter on toast, or yogurt slows further absorption if you have caffeine still pending in your stomach, and stabilizes your blood sugar.
- Don’t have more coffee or any caffeinated drink. This sounds obvious but it’s the most common mistake. Adding more caffeine because you “feel weird” makes the dizziness worse.
- Take slow, deep breaths. Caffeine often triggers shallow rapid breathing, which itself causes lightheadedness. Counted breathing (in for 4, hold for 4, out for 6) interrupts the anxiety component.
- Wait it out. The dizziness usually peaks within an hour of onset and fades over 2 to 4 hours. If it’s still as strong after 4 hours, or if new symptoms show up, treat that as a warning sign rather than caffeine alone.
How to prevent coffee dizziness long term
If coffee dizziness is recurrent rather than a one-off, the goal is to figure out which of the underlying mechanisms is driving it for you, and address that specific factor.
- Stay under 400 mg of caffeine per day. The U.S. Food and Drug Administration considers up to 400 mg daily, about three to four 8 oz (240 ml) cups of brewed coffee, generally safe for healthy adults (FDA – Spilling the Beans). Slow metabolizers should aim well below this.
- Eat first. Even a small breakfast slows absorption and flattens the peak.
- Hydrate before, not after. A glass of water 15 minutes before coffee keeps the dehydration component from stacking.
- Switch to half-caf or smaller portions. Most coffee dizziness is dose-related. A 4 oz (120 ml) pour instead of a 12 oz (350 ml) mug delivers a fraction of the caffeine.
- Time it. Caffeine in the afternoon for slow metabolizers can leave residual levels that mess with sleep, which then affects your tolerance the next day. A hard cutoff 8 to 10 hours before bedtime works for most people.
- Consider a CYP1A2 test if you suspect you’re a slow metabolizer. The result changes how you should structure your intake.
- Check your medications. If symptoms started after a new prescription, review your current meds for caffeine interactions with your pharmacist.
When dizziness signals caffeine intoxication or overdose
Most coffee-related dizziness is mild and self-resolving. But caffeine, like any active compound, has a dose at which it stops being safe. The clinical term for this is caffeine intoxication (caffeinism in chronic cases), and severe presentations are recognized as a medical emergency.
How much caffeine is too much?
The Cleveland Clinic and FDA both define daily caffeine doses by these thresholds (Cleveland Clinic – Caffeine Overdose):
| Dose (per day) | Risk level for healthy adults |
|---|---|
| Up to 400 mg | Generally considered safe |
| 400 to 600 mg | Side effects increasingly common: jitters, sleep disruption, dizziness |
| 1,000 to 1,500 mg | Caffeinism, chronic toxicity symptoms |
| 5,000 to 10,000 mg (single dose) | Potentially fatal range |
For reference, an 8 oz (240 ml, about 1 standard cup) of brewed coffee contains roughly 95 mg of caffeine. An espresso shot is about 60 to 75 mg. Modern energy drinks run anywhere from 80 mg (Red Bull, 250 ml can) to 300 mg (Bang, 480 ml can). Caffeine pills are typically 100 to 200 mg each. Pure caffeine powder, which the FDA has issued specific consumer warnings about, contains roughly 1,000 mg per quarter teaspoon, far past the safe-handling threshold for an untrained user.
Symptoms of caffeine overdose
The medical literature distinguishes mild from severe presentations (NCBI Bookshelf – Caffeine Toxicity (StatPearls)):
Mild caffeine intoxication:
- Restlessness, anxiety, irritability
- Hand tremor and muscle twitching
- Heart palpitations or fast heart rate
- Nausea, stomach upset
- Headache
- Insomnia
- Increased urination
Severe caffeine intoxication (medical emergency):
- Persistent vomiting
- Chest pain or pressure
- Severely irregular heart rhythm
- Confusion, hallucinations, or altered mental state
- Seizures
- Difficulty breathing
- Dangerously high or rapidly dropping blood pressure
Severe symptoms need emergency care. In the United States, call 911 or contact Poison Control at 1-800-222-1222. They provide free, immediate, expert advice 24 hours a day.
Who actually overdoses on caffeine?
Fatal caffeine overdose from coffee alone is virtually unheard of. The volume required to reach a lethal dose, roughly 50 strong cups in a short period, makes it physically difficult. Cases that reach the emergency room or coroner’s office almost always involve one of three patterns:
- Pure caffeine powder or highly concentrated supplements. The FDA has explicitly warned consumers that quarter-teaspoon dosing errors with caffeine powder can be fatal.
- Caffeine combined with other stimulants in pre-workout supplements or weight-loss products.
- Adolescents combining energy drinks with energy shots, caffeine pills, or other caffeinated products without realizing how the doses add up.
The MedlinePlus reference on caffeine overdose notes that emergency presentations have increased over the past decade, driven primarily by the proliferation of high-concentration energy products rather than ordinary coffee consumption (MedlinePlus – Caffeine overdose).
When to see a doctor about caffeine dizziness
Most caffeine dizziness doesn’t need medical evaluation. The following do:
- Dizziness that lasts more than 12 hours after a single cup of coffee
- Daily or near-daily dizziness with no clear pattern relative to caffeine intake
- True vertigo (room spinning) rather than lightheadedness
- Falls or near-falls from coffee-related lightheadedness
- Severe heart palpitations or any chest pain alongside the dizziness
- Dizziness that doesn’t match the caffeine dose, like a single cup producing strong symptoms when previously tolerated
- Dizziness alongside neurological symptoms: weakness on one side, vision changes, slurred speech, sudden severe headache
- Dizziness during pregnancy, where extra precautions apply (see below)
The Mayo Clinic’s general guidance on dizziness causes (Mayo Clinic – Dizziness Causes) lists more than two dozen possible underlying conditions, several of which can be unmasked or made worse by caffeine. A doctor’s visit is the right step to rule them out, rather than assuming caffeine is the cause.
Special populations: when extra caution applies
During pregnancy
The American College of Obstetricians and Gynecologists currently advises that caffeine intake during pregnancy be limited to less than 200 mg per day. Higher intakes have been associated in some studies with increased miscarriage risk and lower birth weight. Pregnancy itself slows caffeine metabolism considerably. The half-life can stretch from 5 hours to 11 hours or more in the third trimester, which means the same cup hits harder and lasts longer. Dizziness from coffee during pregnancy is a sign to cut back further and to consult an OB-GYN if it persists.
Adolescents and energy drinks
The American Academy of Pediatrics recommends that energy drinks have no place in the diet of children and adolescents. Several factors combine to put adolescents at the highest population-level risk for caffeine intoxication: higher caffeine content per serving than coffee, the marketing of “shots” and concentrated formats that hide effective dose, and the smaller body weight of younger users. Dizziness in a teen after an energy drink is more concerning than the same symptom in an adult coffee drinker, particularly if multiple caffeinated products were consumed.
Anxiety and panic disorders
People with diagnosed anxiety disorders, particularly panic disorder, are highly sensitive to caffeine’s stimulant effects. The cardiac and respiratory sensations caffeine produces (racing heart, shortness of breath, lightheadedness) overlap with panic attack symptoms and can trigger a full attack. Caffeine reduction is one of the standard non-medication interventions in anxiety treatment, and dizziness from coffee in someone with a known anxiety condition is a useful signal to drop intake.
Hypertension and cardiovascular conditions
Caffeine produces a transient blood pressure rise that adds to whatever underlying elevation a person already has. The Mayo Clinic notes this is generally well-tolerated in well-controlled hypertension but can be problematic in poorly controlled cases or in people taking certain blood pressure medications. Dizziness in this group, particularly orthostatic dizziness, is worth reporting to the prescribing physician.
Frequently asked questions
Yes. People who are slow caffeine metabolizers, who drink coffee on an empty stomach, or who have certain underlying conditions can feel clear dizziness from a single 8 oz (240 ml) cup. About 10 to 15 percent of the population are slow metabolizers and feel caffeine effects much more strongly than fast metabolizers at the same dose.
Most coffee dizziness peaks 30 to 60 minutes after the cup and resolves within 2 to 4 hours. Slow metabolizers may feel residual effects for 6 to 10 hours. Dizziness lasting more than 12 hours after a single cup is unlikely to be caffeine alone and should be checked.
Lightheadedness without jitters usually points to the cerebral vasoconstriction or blood pressure mechanisms rather than the central nervous system stimulation that produces jitters. People sensitive to the vascular effects but tolerant of the stimulant effects can feel lightheaded without the typical “wired” sensation.
Coffee rarely causes true vertigo (the sensation of motion or spinning) directly. It can trigger or worsen vertigo episodes in people with underlying vestibular conditions like Meniere’s disease or vestibular migraine. If your “coffee dizziness” is actual room-spinning vertigo, see a doctor. Caffeine is more likely an aggravator than the cause.
Caffeine on an empty stomach is absorbed in 15 to 30 minutes versus 45 to 90 minutes with food. Faster absorption means a higher peak blood concentration, which produces stronger effects, including dizziness. A small breakfast before coffee flattens the peak and reduces symptoms.
The U.S. FDA considers up to 400 mg of caffeine per day generally safe for healthy adults, roughly three to four 8 oz (240 ml) cups of brewed coffee. Pregnant women should stay under 200 mg. Slow metabolizers should aim well below the general limit. Doses of 1,000 mg per day produce caffeinism (chronic toxicity), and single doses above 5,000 mg can be fatal.
Loss of consciousness from caffeine alone is rare but possible at very high doses, usually involving caffeine pills, powder, or multiple energy drinks rather than coffee. The mechanism is typically a vasovagal response to the rapid heart rate and blood pressure swing rather than the caffeine itself. Anyone who actually loses consciousness after caffeine should be evaluated in an emergency setting.
The “caffeine drunk” feeling (disoriented, slightly slurred thinking, lightheaded) happens at high doses or in slow metabolizers. It’s the combined effect of cerebral vasoconstriction (less brain blood flow), blood pressure swings, and adenosine receptor blockade producing temporary cognitive effects. Uncomfortable but generally not dangerous, though it’s a clear signal that you’re past your tolerance and should not have more caffeine that day.
Not necessarily. The first step is to figure out which mechanism is producing the dizziness for you and address that, usually by eating before coffee, hydrating, reducing the dose, or switching to half-caf. If those changes don’t help and dizziness keeps happening, then yes, switching to decaf or eliminating caffeine is reasonable. Dizziness that continues after eliminating caffeine should be checked by a doctor.
Yes. Decaf coffee contains 2 to 7 mg of caffeine per 8 oz (240 ml) cup compared to about 95 mg in regular coffee, low enough that the mechanisms behind caffeine dizziness don’t engage meaningfully. Half-caf splits the dose in half and is a useful intermediate step. Note that decaf still contains the other components of coffee (chlorogenic acids, oils), so if your dizziness is from something other than caffeine, decaf may not solve it.
Sources and references
- U.S. Food and Drug Administration – Spilling the Beans: How Much Caffeine is Too Much?
- Mayo Clinic – Caffeine: How much is too much?
- Mayo Clinic – Dizziness: Causes
- Cleveland Clinic – Caffeine Overdose: How Much Caffeine Is Too Much?
- MedlinePlus Medical Encyclopedia – Caffeine overdose
- NCBI Bookshelf – Caffeine Toxicity (StatPearls)
- Guest, N. et al. – Impact of CYP1A2 Genotypes on the Effects of Caffeine Ingestion. Nutrients, 2024.
- Addicott, M. A. et al. – The effect of daily caffeine use on cerebral blood flow. Human Brain Mapping, 2009.
- National Capital Poison Center – How Much Caffeine Is Safe?
This article is for general information only and does not replace personalized medical advice. If you’re concerned about caffeine’s effect on your health, talk to your healthcare provider. In the case of suspected caffeine overdose, call Poison Control at 1-800-222-1222 (US) or your local emergency services.
Discussion 10
I started drinking coffee in order to stay awake on my drive to and from work. It wasn’t working that well anymore so I switched to Starbucks espresso roast that you buy at the store. For two days I poisoned myself with it and had no idea why I was dizzy, nauseated, had jumbled thoughts, and get faint and flush. I thought Ihad caught a stomach bug, the next day I began wondering if I was pregnant! Until a coworker mentioned coffee! ! Ugh. There should be warning labels!
Personally I hate caffeine…each time I drink green tea, ice tea or coffee I get dizzy… I remember last time when I decided to try all of them (tea, redbull and coffee) I didn’t slept for 4 days in a row…lol my heart was pumping rally fast… I tought I was going to die! :D I don’t know how many grams I took but all I can say watch out!
Hello three years ago :D
Ummm… Yeah, this is really scary. I drank a can of Burn (energy drink, 500ml can contains 160mg caffeine) yesterday. That was trying to stay awake for school after about 24 hours of no sleep. After that, we went for a trip up a mountain, and I noticed I wasn’t as tired as I should have been. Also, after about 10 hours of sleep, I woke up, not tired at all, and after reading up on caffeine (38 hours without sleep and not tired makes me suspicious), I checked my heartbeat, and found I have about 115bpm.
And some information so it’s easier to know how bad the symptoms are: 14yo, 110lbs, 5’7″
Anyone able to explain how only one can of Burn was this effective?
I’ve been very sensitive to caffiene for about 5 or 6 years (I get jittery). Recently,I have been feeing dizzy after having a large caffienated soda. I thought there was someting wrong with me! I didn’t know dizziness was a side effect. I think I’m done with caffiene now.
Most days I have about 200 mg caffeine. All it does is calm me down. I had a caffeine pill and an energy drink the other day, which all up is 270mg caffeine and I just sat there, staring at one spot.
Caffeine has the opposite effect on me.
And Brooke, i’ve never had over 2 grams of caffeine in a day and I’m really addicted. It’s doubtful you had 6 grams of caffeine in a day. That is an amazing amount.
When Im mad or upset i grab my phone to call my sister and grab some caffeine. ITs like my anti depressant of sorts. When ever were together we drink alot of it. She deffinatly is “addicted” to it. She cant go 7 days with out it. Getting intoxicated by it can be really fun. The excitment the twitching, the nonstop laughing, not being able to sleep. I’m normal the one who stutters.
She’ll have like 3 cans of it and call me at the most random moments SOOOOO hyper. I really get worried about her. I dont think I’ve ever gotten over 6 grams of it. Her. I really dont know. We had to test her for diabetes. My parents hate it Soda because of the amount of sugar. And they hate energy drinks.
MY family situation is kinda messed up. She lives with my nana and papa who have So much soda its not even thinkable. She always stocks me up and I just hide it in my closet :P. I dont it that often, well, I dont know what you count as often. But about once or twice a week I get high up there. After a long day its fun. Then crashing afterwards is really easy
Natalie, that is interesting. I, too, might only one one small iced chai tea, per day, and almost every time I do, I get dizzy spells (vertigo issues). I’m glad I’m not the only one. I never used to have the problem and it’s very frustrating. I love my chai. I think the tea is not more than 50 mg. of caffeine, either. I’d like to know why it affects us that way?
Even one cup of coffee makes me sick. I don’t drink it very often, but if I have coffee three days in a row and one cup per day I get dizzy spells and bad headaches. I almost fell over one time.
Interesting. Makes you wonder how much anxiety could being easily taken care of by telling folks to switch to decaf, or lay off.
I’ve notice some dizziness after a hard workout if I drink coffee before, very rarely but it does happen. When it does I know it is time to slow down and drink decaf.