Leg Day Observer

Is coffee before workouts good or bad? The benefits of caffeine, explained

Caffeine has been shown to increase performance in strength sports, high-intensity exercise, and sprints.

Top view of a cup of coffee in the form of Arm muscle on red background, Coffee concept illustration...

What if I told you that there was a legal, cheap, and widely accessible psychoactive substance that could instantly improve your workouts?

Though we tend to consume it when we start our day, caffeine functions a lot like a supplement. In the same way that we down protein powders or bars when we can’t choke down a real meal after a lift or take pre-workouts before a difficult leg day, caffeine is something we use that can help us squeeze out a couple more reps and add on a couple of extra exercises at the end.

But unlike most supplements, caffeine’s not an extra. For all of the development behind protein powders — whey separated from curds, or concentrated pea and rice proteins — they don’t offer anything new. They help us ensure a good macronutrient ratio, but are no different from food. They aren’t better than eating real food, they’re just faster.

But caffeine has its own special purpose. It’s been shown to increase performance in strength sports, high-intensity exercise, and sprints — something lifters should be doing anyway. It can even aid recovery when consumed after workouts.

“Caffeine, taken in moderation, is just about the safest bet you can make.”

Ingesting 5 mg of caffeine per kilo of body weight, minus one kilogram, has been shown to increase strength. In a study performed by researchers in Brazil, caffeinated athletes lifted 11% more on bench press than the control group. (Most cups of black coffee have about 100 mg of caffeine, while energy drinks tend to have more.)

Another study found caffeine significantly improves upper body strength, as measured by a one-rep max — though not lower body strength. The hits keep coming: Caffeine has been found to have an indirect positive effect on mood and concentration, which leads to better reaction times, which makes it a sort of cognitive enhancer: caffeinated lifters might swing a kettlebell better, or move quicker. Caffeine has been shown to create a more favorable interaction between brain cells and muscles — proprioception, or what earlier columns have referred to as a greased groove. In a very rough way, drinking some coffee before a workout gives lifters the same result as if they’d done an exercise over and over again, and that sort of familiarity increases force production.

Nothing you buy can ensure a good workout, but caffeine, taken in moderation, is just about the safest bet you can make, outside sleeping and eating well, to ensure a good workout. Or perhaps to ensure a workout where the lifter is present, and paying attention. A cup of coffee before a workout might make up for a rough workday or a night spent tossing and turning. It could even help a lifter squeeze out a couple of reps. And if the lifter has good habits to begin with, it will help the workout be something.

All this, if we weren’t talking about caffeine, would make a substance seem like a miracle. But since we know how coffee works, it’s slightly less mystical. Just as most people wouldn’t show up to work uncaffeinated, we shouldn’t sleep through our workouts, either.

The best way to caffeinate your workout


With all the rafts of pre-workouts available, it’s reasonable to think we might need caffeine to enter our bodies in some technical way. Isn’t more better? But coffee actually works pretty well, and the problems we have with over-caffeination outside the gym — anxiety, insomnia, irritability, fast heartbeat — don’t go away just because you’re lifting. Studies have also found that caffeinated individuals don’t get much stronger from the extra caffeine, and that results taper off. (This is slightly obvious, of course drinking coffee doesn’t make you stronger.) Additionally, people can become tolerant of its effects over time.

Avoiding caffeine can also be harmful, or at least inefficient. Some people claim caffeine cancels out the positive effects of creatine, an organic acid that’s been shown to improve strength. But that has been disproven.

To be sure, caffeine has negative effects. In addition to what happens when you ingest too much, caffeine is a diuretic, which can feel dehydrating and draining. It’s worth wondering whether these general side effects are worth mortgaging a workout for. You can take caffeine before a workout, and drink a bit less coffee during the day to balance out. It doesn’t hurt to blast an espresso shot before a squat session — and if you have a good workout you’ll feel better later anyway.

Workouts: Caffeine vs. supplements

Sviatlana Yankouskaya / EyeEm/EyeEm/Getty Images

Caffeine is so commonplace it’s often taken for granted. But it’s also quite clarifying. Taking caffeine is an admission that lifters sometimes (or regularly) need help to get through a workout, and maximize it, and that focus and clarity don’t always show up when you need them to. It also shows that individual workouts are important. Each rep and day at the gym is the most crucial part of why we work out. Even the most dedicated lifters are only in the gym a few hours a week. So we should all do our best to make the most of these sessions.

It also helps put in perspective what supplements mean. With so many pre-workouts often just being glorified coffee pills, we might wonder how much we need other supplements to get stronger. Should we rely on protein powders to hit our macronutrient targets? Should we lean on magnesium to combat soreness — or should we get enough food and rest?

Caffeine is an admission that each workout is important.”

We probably shouldn’t be living off powders and pills. But it’s complicated. There’s nothing wrong with wanting an edge, and the extra advantage a serious pre-workout gives makes it valuable both to competitive lifters and very strong people. While whole foods are better, they’re expensive, and the stuff that ‘70s era bodybuilders like Arnold subsisted off doesn’t really exist today: the food they ate then was pretty much organic, without pesticides, and mostly natural. In many ways, our decision to supplement now isn’t as stark as how it might have been in the past.

Caffeine, then, is both the rule and exception: a slightly unnatural way to attack a lifestyle that itself is a little unnatural. We need help, sometimes before every workout — but all of us seem to need the same sort of help before we clock in to work. Caffeine, at its best, is an admission that each workout is important, and needs to be focused on, and separated from the rest of the day. This is something we know, but may not always follow. With science behind it, it’s a little easier to stick to the script.

LEG DAY OBSERVER is an exploratory look at fitness, the companion to GQ.com’s Snake America vintage column, and a home for all things Leg Day. Due to the complicated nature of the human body, these columns are meant to be taken as introductory prompts for further research and not as directives. Read past editions of Leg Day Observer for more thoughtful approaches to lifting and eating.

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