It goes with the turf: runners consistently try to make the most out of their workouts. Whether that’s improving their time or feeling more conditioned during their sprints. Some want a little more pep in their step—in the most literal sense—and others just want to feel less like they’re on auto-pilot.

But is it bad to drink coffee before running? There are certainly pros and cons to drinking coffee before running.

Benefits of Caffeine on Exercise

There are plenty of researched benefits to coffee before a run. Coffee before a run, on the whole, will better your performance—but what does that mean?

• Endurance. Put simply, caffeine will trick your body into thinking it’s not working as hard as it really is. This means that, for as long as the caffeine is doing its job, your body will do its job more effectively and for longer. It’s about perception, as well as some clever employment of caffeine to make better use of fat as fuel, which should reassure coffee drinkers and runners looking to lose weight.
• Heat tolerance. Coffee before a run has another surprising benefit: it regulates body temperature. That means your body will tolerate hot summer runs better. Most of the studies surrounding this measure the performance of cyclists, but this should extend to runners as well.
• Running faster. Studies that have examined performance in 5K races with caffeine show an approximate one-percent increase in performance—which is significant when every second counts.

This is all in addition to the antioxidant benefits that come with drinking coffee. Coffee is known to fight inflammation and enhance anti-inflammatory processes that already happen during exercise – especially in the liver.

To optimize benefits, experiment with varying amounts of caffeine before going for a run. And remember that the effects of caffeine can last for hours; there’s no need to chug a cup of coffee minutes before a morning run to get its full benefit.

Risks of Caffeine Before a Run

Coffee drinkers are probably familiar with the obvious cons of drinking coffee before a run: it’s a diuretic. Some people report gastrointestinal problems when prefacing their runs with a cup of coffee, particularly if you’re someone who adds milk and sugar to a cup of coffee.

Meanwhile, science is conflicted about whether to worry about the dehydrating effects of caffeine. A 2007 study by researchers at the University of Connecticut found that caffeine intake does not cause water-electrolyte imbalances. Other research suggests the amount of caffeine consumed actually has little impact on dehydration. In sum, though many may report an increase in urination in the hours following caffeine intake, there is no net fluid loss. In other words, your body retains more than it’s putting out.

That said, it’s also true that we’re all genetically made differently when it comes to metabolizing caffeine. So, the risks of caffeine consumption may be individualized. And, naturally, those who drink caffeine more often will probably notice fewer side effects if drinking coffee before running.

Can I Drink Coffee After Running?

You sure can.

In tandem with carbohydrates, which are essential to rebuilding your muscle glycogen stores after a run, caffeine enhances that process by almost 66%, according to a 2011 study by researchers at Liverpool John Moores University. The key, of course, is to still focus on consumption of carbohydrates, and not combining the caffeine and carbohydrates with added sugars—so, watch out with certain sports drinks.

Drinking coffee after a run can be A-OK—just drink it, whether before or after a run, in moderation.