We all need a little boost of energy to get us amped up to crush our workouts, but can espresso serve as a pre-workout drink? As a regular coffee drinker with a pretty high tolerance, I find myself brewing espresso shots before heading to the gym at least a few times of week (especially for those late-afternoon workouts where the 3 p.m. slump hits hard). At about 64 milligrams of caffeine per shot of espresso, espresso has enough caffeine to provide a bit of a pick-me-up before exercising.

Should you drink espresso before exercise? Below, Dr. Gail Clifford, M.D., a physician for over 30 years, shares her thoughts on drinking espresso before working out.

What happens when you drink espresso before a workout

“Drinking espresso before a workout can give you a quick boost of caffeine that can increase your alertness and energy levels and can help you feel more ready for your workout,” says Dr. Clifford. Overall, the caffeine in espresso can make your workouts feel easier and more energized, especially if you’re exercising early in the day, as caffeine stimulates the central nervous system and raises your adrenaline levels to promote the release of fatty acids for fuel.

“Caffeine also increases heart rate and blood flow to help increase the delivery of oxygen and nutrients to working muscles,” she says. Many use caffeine in espresso to help sharpen focus during workouts, too, making it easier to continue endurance exercises for longer with less perceived strain.

“Drinking espresso before a workout can also increase calorie burn since caffeine can boost fat oxidation and metabolic rate. This means that espresso can help your body burn slightly more fat and calories during activity,” she says. “While the effect is mild when used once or every so often, it can add up when used frequently during training.”

How and when to drink espresso before a workout

If you’d like to use espresso as a pre-workout boost, Dr. Clifford says timing is key. “Caffeine from espresso starts working within about 15 to 30 minutes after drinking and peaks around 45 to 60 minutes. Its effects can last anywhere from 3 to 5 hours, depending on your metabolism, if you’ve eaten, and how hydrated you are.”

For most people, she recommends consuming one to two shots of espresso about 3o to 60 minutes before starting a workout session (around 60 to 120 mg of caffeine).

At the same time, she cautions espresso drinkers to be mindful of the potential downsides of having too much caffeine, such as jitters, anxiety, increased heart rate, or restlessness — which ultimately can impact your workout negatively. Those who are sensitive to stimulants or who work out on an empty stomach should be mindful of having too much caffeine before exercise. Staying hydrated and moderating how much caffeine you have can help reduce unwanted effects.

“In excess, caffeine can negatively affect hydration and recovery following your workout since too much caffeine can have a mild diuretic effect,” she warns.

Should you drink espresso before exercise?

Overall, Dr. Clifford says espresso can be a good pre-workout drink, since it provides fast, natural, and low-calorie energy that can boost performance and motivation without added sugars or synthetic ingredients:

“When compared to traditional pre-workout supplements, espresso offers similar stimulant benefits such as focus, alertness, and endurance, but is natural and does not contain any artificial additives or high doses of stimulants that can cause crashes or side effects. When timed and dosed properly, using espresso as a pre-workout drink can help improve performance and focus.”