Lace-up your sneakers. Shake out your muscles. And down a mug of coffee. For some runners, coffee before running is a non-negotiable part of the routine – a ritual so embedded in the norm that a workout just wouldn’t feel right without it.

If that’s you, good news: Drinking coffee prior to a run can offer very real performance benefits, including decreased fatigue and reduced perceived exertion, among other perks. But it’s not one-size-fits-all. Depending on how much coffee you imbibe and your individual sensitivity to caffeine, downing a triple-shot espresso before you hit the trails may do more harm than good.

Amity Lui, a registered dietitian, who works with runners, says clients often ask about having coffee before running, posing questions like: “Should I be drinking coffee? How much coffee should I drink? How much is too much? When should I drink it?”

Here, she helps to answer those questions, fielding all you need to know about coffee before running, including the perks, drawbacks, and expert advice for incorporating it into your routine.

The benefits of coffee before running
Most of coffee’s benefits before running are specific to caffeinated coffee. “Caffeine is a legal ergogenic aid,” explains Lui. That means it can enhance your performance, according to research.

One review published in the International Journal of Sport Nutrition and Exercise Metabolism noted that for endurance running specifically, caffeine can lessen perceived effort, tiredness, and pain while boosting alertness and vigilance.

The effects of caffeine use seem to most consistently provide moderate-to-large benefits for aerobic endurance activities, according to a 2021 paper published by the International Society of Sports Nutrition. That said, “small to moderate benefits of caffeine use” are seen in sprinting, muscular endurance, and muscular strength, among many other sports activities, per the paper.

Another effect of coffee: It can make you poop. Both caffeinated and decaffeinated coffee can trigger a reflex that leads to bowel movements, explains Lui. This can be a pro or a con of coffee, depending on the context, she says. For example, if you’re trying to empty your bowels before you leave home (and the comfort of a nearby toilet), then coffee may help. But if you gulp coffee and start running before you’ve gone number two, well, things could quickly backfire.

One more benefit of coffee is that it contains antioxidants, which are helpful for anyone to consume but especially athletes, as antioxidants work to reduce the body’s inflammatory response to exercise, says Rachel Gargano, MS, RD, CSSD, a registered dietitian specializing in sports nutrition with Top Nutrition Coaching.

The downsides of coffee before running
When it comes to coffee before running, more isn’t always better. Depending on your tolerance for caffeine, having too much of it can increase your risk of anxiety and heart rate abnormalities while decreasing your ability to do fine motor movements, says Lui. You might start sweating, get clammy hands, and feel jittery, she adds.

Also, as mentioned, coffee can trigger a bathroom break, which may be a downside in certain circumstances.

Moreover, taking in a lot of caffeine late in the day can disrupt your sleep. That’s because the average half-life of caffeine is about five hours, says Lui, meaning it takes about five hours for half the amount of caffeine you ingested to dissipate from your system. Say, for example, you drink a cup of coffee with 200 milligrams of caffeine at 3 p.m. before your afternoon run. By 8 p.m., 100 milligrams of caffeine will still be left in your body. Depending on how sensitive you are to caffeine, you may have a tough time falling or staying asleep that night, says Lui.

How to determine how much coffee to have before a run and when to have it
Wondering how much coffee you should down before a run? There isn’t a set amount for everyone, because people’s tolerance for caffeine depends on a number of things including genetics, how long you’ve been consuming caffeine, and how much you typically take in on a daily basis.

That said, the general recommendation for performance is three to six milligrams of caffeine per kilogram (kg) of body weight, say Lui and Gargano. So for an athlete who weighs 68 kg (150 pounds), that would be about 200 to 400 milligrams—the equivalent of about two to five cups of coffee.

If you’re sensitive to caffeine, then you would likely want to err on the lower end of that spectrum, says Gargano. But “if you’re already taking in a decent amount of caffeine on a daily basis, then you probably need a bigger dose to be effective,” she adds.

Keep in mind: “There is such a thing as too much caffeine,” says Lui. You may want to stick to 400 mg or lower, according to the Food and Drug Administration (FDA), which warns that over-consuming caffeine can lead to issues including upset stomach, insomnia, anxiousness, and fast heart rate, among other concerning side effects. Additionally, when people rapidly take in a very large volume of caffeine (think: about 1,200 milligrams), it can cause toxic effects including seizures, per the FDA.

If you find you’re ultra-sensitive to caffeine in a negative way, then Gargano doesn’t advise making coffee a part of your running routine, because the downsides likely outweigh any potential benefits.

But, if you seem to tolerate caffeine well, then the general recommendation is to have it about 30 to 60 minutes before you head out for your run, says Gargano. You’ll notice the effects of caffeine as quickly as 15 minutes after consuming it, but its full influence peaks around one hour later, says Lui, who suggests timing your pre-run coffee consumption so that you receive “that little boost when you need it the most.”

In a pre-run situation, if you’re someone who adds a good dose of real sugar to your coffee, then you may want to consume it closer to your run—within 30 minutes or so, says Gargano. That’s because “sugar is going to hit the system pretty quickly, and to take advantage of high blood sugar levels, which is beneficial for when you are exercising, you’d want to get that a little closer” to the start of your workout, she explains.

Note that if you’re running long—like more than two hours—that might mean taking caffeine in during your run, says Gargano. In that case, you’d probably opt for a caffeinated chew or gel.

The bottom line on drinking coffee before running
Drinking coffee before a run can provide legit perks—including increased alertness and reduced fatigue, pain, and perceived effort—but it’s not beneficial for everyone. It takes some practice to figure out how much coffee (if any) is a worthy part of your pre-run ritual, and then also to determine the best dose and timing for you.

No matter how you take your coffee or when, both experts recommend pairing it with some type of food to ensure you have the energy you need to perform well in your workout. “Coffee itself does not provide energy because it’s not a calorie-based food,” explains Lui.

Gargano recommends having an easy-to-digest carbohydrate snack within 30 to 45 minutes of starting a run. Good pre-run snack options, according to Lui, include a slice of toast with a banana and honey, a banana with peanut butter, or applesauce for those who have trouble tolerating solid foods before exercise.

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