Coffee Before a Workout: How Caffeine Affects Performance, How Much and When

A cup of coffee before you train is one of the simplest, best-studied ways to get a little more out of a workout. Caffeine can help you push a bit harder, last a bit longer and feel like the effort is easier. It also has limits and downsides worth knowing, from jitters and upset stomachs to poor sleep, and energy drinks bring risks that plain coffee does not.

This guide covers how caffeine affects exercise, how much and when to drink, coffee vs. pre-workout supplements, energy drinks, coffee vs. tea, bulletproof coffee, side effects, how much caffeine is safe, and how to cut back if you need to.

The short version

• Caffeine can modestly improve endurance, strength and power, and make hard efforts feel easier.
• Research doses are about 3 to 6 mg of caffeine per kilogram of body weight, taken about an hour before exercise. Many people do well with less, such as one or two cups of coffee.
• Coffee works as a caffeine source. You do not need a pre-workout supplement.
• For most healthy adults, up to 400 mg of caffeine a day is not generally linked to negative effects. Pregnant people should stay under 200 mg.
• Stop caffeine at least 6 hours before bed, since it can cut into your sleep and recovery.
• Energy drinks are not the same as coffee. Be cautious with them, never mix them with alcohol, and keep them away from kids and teens.

How caffeine affects your workout

Caffeine is one of the most researched performance aids in sports nutrition. It works mainly by blocking adenosine, a chemical that builds up in the brain and makes you feel tired. The result is more alertness and a lower sense of effort.

• Endurance: the most consistent benefits are in longer aerobic exercise such as running, cycling and rowing.
• Strength and power: caffeine can modestly improve muscular endurance, strength and power in many people.
• Perceived effort: hard work tends to feel a little easier, which helps you keep going.
• Focus and reaction time: caffeine improves alertness and attention, which can help in skill sports.

The effects are real but usually modest, and people respond differently. Genetics, body size, sleep and how much caffeine you normally have all play a part. Caffeine also increases fat use during exercise to some degree, but that does not mean coffee is a weight loss tool.

How much caffeine and when

Studies that show performance benefits typically use about 3 to 6 mg of caffeine per kilogram of body weight. For a 150-pound (68 kg) person, that is roughly 200 to 400 mg. Doses as low as about 2 mg per kilogram (around 135 mg for that person) may also help, and very high doses add side effects without much extra benefit.

Caffeine content varies a lot by brand, brew strength and cup size, so treat these as rough guides. A large coffee from a coffee shop can easily have 300 mg or more.

Timing: caffeine is usually taken about 60 minutes before exercise, when blood levels are close to their peak. Thirty to 60 minutes works for most people. For an early workout, a cup on the way out the door is fine. For tips on timing your first cup of the day, see our post on the 90-minute rule for morning coffee.

Start low. If you are new to caffeine before exercise, try one cup on an easy training day first, and never try a new dose before a race or big event.

Coffee vs. pre-workout supplements

Most pre-workout supplements contain caffeine. Coffee delivers it in a familiar, inexpensive form.

• Coffee: no added ingredients, and you can easily adjust how much you drink, though caffeine per cup varies.
• Pre-workouts: often contain high caffeine doses, sometimes stacked with other stimulants, plus ingredients such as beta-alanine (which causes harmless tingling) and citrulline. Doses vary widely between products.

Dietary supplements are not approved by the FDA before they are sold. If you use one, choose a product tested by an independent third party, such as NSF Certified for Sport, and count its caffeine toward your daily total.

What to eat and drink with your pre-workout coffee

• Pair it with a light snack if you train for more than an hour or have not eaten, such as a banana, toast or yogurt. Coffee on an empty stomach upsets some people.
• Keep add-ins light before training. Heavy cream, large sugary drinks and big blended coffees can sit heavily in your stomach.
• Drink water too. Moderate caffeine does not dehydrate regular coffee drinkers, but it does not replace water before and during exercise.

After training, focus on protein, carbohydrates and fluids. See our guide to whether to have a protein shake before or after a workout.

Energy drinks: what to know

Energy drinks are not just fizzy coffee. Many contain high doses of caffeine, often in large cans that are easy to drink quickly, along with a lot of sugar or other stimulants. They have been linked to emergency room visits for problems such as a racing or irregular heartbeat, anxiety and insomnia.

• Check the label for the caffeine per can, and count it toward your daily total.
• Do not mix energy drinks with alcohol. Caffeine can make you feel less drunk than you are, which can lead you to drink more.
• Avoid them if you have a heart condition, high blood pressure or an anxiety disorder, unless your doctor says otherwise.
• Keep them away from kids and teens. The American Academy of Pediatrics advises that energy drinks have no place in their diets.
• Watch the sugar. Some cans contain more added sugar than you should have in a whole day.

The caffeine crash and dependence

Regular caffeine use leads to some tolerance and dependence. When the effect wears off, or when you skip your usual dose, you may feel tired, foggy or irritable. That can turn into a cycle of reaching for more caffeine to feel normal, especially with energy drinks.

Caffeine withdrawal is real. Symptoms such as headache, tiredness, low mood and trouble concentrating usually start within 12 to 24 hours of your last dose and can last a few days to a week or so. If you want to cut back, taper gradually over a week or two rather than stopping all at once.

Caffeine, sleep and recovery

Sleep is when your body recovers from training, and caffeine can get in the way. Its effects last for hours, and caffeine taken even 6 hours before bed can reduce sleep. If you train in the evening, consider skipping caffeine or having a smaller dose earlier in the day. For more, see our sleep guide.

Coffee vs. tea

Both can be part of a healthy diet. In large observational studies, moderate coffee drinking and tea drinking are both linked with good health outcomes, though these studies cannot prove cause and effect.

• Coffee has more caffeine per cup, which makes it the more practical pre-workout choice for most people.
• Tea has less caffeine, so many people find it gives a gentler lift. It also contains L-theanine, which may have a mild calming effect, though a cup has only a small amount and the evidence is limited. Green tea or a strong black tea can work if coffee makes you jittery.

Either way, the add-ins matter. A black coffee or plain tea is very different from a large sweetened latte or bottled sweet tea.

Bulletproof coffee

Bulletproof coffee is coffee blended with butter or ghee and MCT oil. It is popular with people following keto or intermittent fasting plans. It can feel filling, but it is high in calories and saturated fat, and there is little evidence that it improves energy, focus or weight loss beyond what the caffeine itself provides.

If you like it, treat it as part of a meal rather than an extra, and keep an eye on your overall saturated fat intake. Before a hard workout, the fat can sit heavily in your stomach. For more on these eating styles, see our guides to keto and intermittent fasting.

Side effects and who should be careful

Common side effects of too much caffeine include jitters, anxiety, a fast heartbeat, an upset stomach, headaches and trouble sleeping. Talk to your doctor before using caffeine to boost workouts if you:

• Are pregnant, trying to get pregnant or breastfeeding
• Have a heart condition, high blood pressure or heart rhythm problems
• Have an anxiety disorder or panic attacks
• Have acid reflux or stomach problems that caffeine makes worse
• Take medicines that interact with caffeine, such as some antibiotics (like ciprofloxacin), stimulants or the antidepressant fluvoxamine

How much caffeine is safe?

For most healthy adults, the FDA says up to 400 mg of caffeine a day, about two to three 12-ounce cups of coffee, is not generally associated with negative effects. People who are pregnant should keep caffeine under 200 mg a day, the limit used by the American College of Obstetricians and Gynecologists. Sensitivity varies, so less may be right for you, especially if caffeine affects your sleep or makes you anxious.

Very high doses can be dangerous. Concentrated caffeine powders and liquids are especially risky, because a tiny amount can contain a toxic dose. Get medical help right away for chest pain, a racing or irregular heartbeat, confusion or vomiting after taking caffeine.

Working with a trainer

Caffeine can give you a small edge, but consistent training, good sleep and solid nutrition do most of the work. A Type A Training trainer comes to your home, your building gym or a park in Manhattan and builds a program around your goals. If you want help with what you eat and drink around training, see our nutrition services.

Frequently asked questions

Is it good to drink coffee before a workout?

For most healthy adults, yes. A cup of coffee about 30 to 60 minutes before training can modestly improve performance and make hard work feel easier. Skip it if caffeine upsets your stomach, makes you anxious or affects your sleep.

How long before a workout should I drink coffee?

About 60 minutes before is typical, and 30 to 60 minutes works for most people.

How much coffee should I drink before a workout?

One or two cups is enough for many people. Studies use about 3 to 6 mg of caffeine per kilogram of body weight, but start lower and see how you respond.

Does coffee before a workout help burn fat?

Caffeine can increase the amount of fat you use during exercise somewhat, but the effect on body fat over time is small. Your overall diet and training matter far more.

Is coffee better than a pre-workout supplement?

For most people, coffee does the job. It gives you caffeine, which most pre-workouts also contain, it costs less, and there are no added ingredients. If you use a supplement, choose a third-party tested product.

Does coffee dehydrate you before exercise?

Not in moderate amounts, especially if you drink coffee regularly. Still drink water before and during exercise.

Are energy drinks safe before a workout?

They are riskier than coffee because of high and varied caffeine doses, extra stimulants and sugar. If you use them, check the caffeine per can, stay within safe daily limits, and avoid them if you have heart problems or high blood pressure.

How do I cut back on caffeine without a headache?

Taper gradually, for example by cutting about one cup every few days or mixing in more decaf over time. Withdrawal symptoms usually ease within a week or so.