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The Performance Benefits Of Caffeine

The sports nutrition world is chock-full of tons of supplements containing different ingredients and complex-sounding compounds. Over the years, a few have stood out in the research as especially powerful for supporting your performance and gains. One in particular I want to talk about: caffeine.

Caffeine Basics

Caffeine is the most commonly used performance-booster in the entire world—and considering it comes with few negative side effects or long-term health consequences, its popularity is largely deserved.

Most people use caffeine for that morning or midday pick-me-up, but athletes have been using it to improve performance for decades (if not even longer). In fact, there were even efforts to ban it from use in sport back in 1939. (Yes, the performance benefits of caffeine are that legit.)

Since just about everyone has had some sort of experience with caffeine, let’s start by discussing what it actually is—and how it works in your body.

What Is Caffeine, Exactly?

Caffeine is a natural compound found in several plant sources, with the most common being coffee beans, various teas, and even cacao. Caffeine is considered a stimulant, meaning it “energizes” us (versus substances like alcohol, which are considered depressants).

How Caffeine Works

How exactly does caffeine have this energizing effect, though? In short, it blocks brain receptors for adenosine, which promotes drowsiness and relaxation. When caffeine binds with these receptors instead, it causes the opposite effect: alertness and energy.

Caffeine’s inhibition of adenosine can also impact hormones throughout the body. For example, when people take caffeine, we often also see an increase in epinephrine (commonly referred to as adrenaline). This causes our heart rate to increase, helps our muscles produce more force, and even increases our metabolism.

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Another one of the performance benefits of caffeine: It’s been shown to increase pain tolerance. (That’s why you’ll find it in many OTC pain medications.) This is another reason why athletes and bodybuilders love caffeine so much; it makes the burn of intense training feel slightly less uncomfortable.

One more thing to note: Caffeine also interacts with the muscle cells of the heart, potentially improving its performance. Basically, caffeine helps increase the concentration of calcium—which is required for the heart to produce force—in addition to the heart muscle’s sensitivity to it. The short of it: Caffeine helps the heart pump more blood!

Performance Benefits Of Caffeine: Endurance Training

Endurance exercise is one of the most common activities in which caffeine is used. Studies consistently show a clear benefit of taking caffeine before training or competing—and that it can improve performance in tests of distance or time to exhaustion.

Caffeine’s ability to increase cardiac muscle fiber contractility, improve alertness, and modify circulating hormone levels all support endurance exercise performance.

Read More: I Drank A Gram Of Caffeine A DayHere’s What Happened When I Quit Cold Turkey

The adenosine-blocking effect of caffeine is probably the most important here, since adenosine affects your central nervous system and can contribute to drowsiness and fatigue, making it harder to activate our muscles. (Together, these factors increase your perceived exertion and pain—and, pretty soon, you want to quit.)

Plus, caffeine also promotes fatty acid oxidation, improving your ability to use fat as fuel. Since fat is the primary fuel source in long-distance, low-to-moderate-intensity exercise, this can be a notable performance booster.

Performance Benefits Of Caffeine: Strength Training

Though research has traditionally focused on caffeine’s use in endurance training, it has recently begun to investigate its effects on strength and power performance.

In fact, multiple studies have shown caffeine to improve strength and power performance.

Obviously, caffeine’s alertness benefits play a role in increasing strength—especially if you’re fatigued or feeling unmotivated prior to taking it. However, caffeine’s main role in strength is probably through increasing muscle activation. Since caffeine blocks adenosine, it likely helps us recruit our muscles to perform heavy or powerful lifting.

Studies have found that caffeine may be more effective for improving upper-body strength than lower-body strength. A couple of caveats here, however. Lower-body strength movements are typically more complex and require more training experience and skill than upper-body movements. Plus, these studies typically use untrained or moderately trained subjects. So, these results may simply reflect the unreliability of scientific studies to compare the upper- and lower-body benefits of caffeine in a truly apples-to-apples way. We have to remember that studies are limited by the scientific method, so they may not always apply perfectly to real-world training.

A Note On Caffeine For Older Adults And Women

The limitations of research also influence our understanding of how men and women respond to caffeine. Though we have no reason to think men and women would experience significantly different effects, we unfortunately don’t have much data on female subjects.

Additionally, most of our current data is on young adults. It remains to be seen if older adults have a notably different exercise response to caffeine. That said, I have a hunch that caffeine might be even more effective for older populations—especially when it comes to strength and fatigue.

Caffeine Dosages and Safety

Studies have pretty consistently found that the effective dosage for caffeine is somewhere between three and six milligrams per kilogram of bodyweight. (For a 200-pound individual, that comes out to 272 to 545 milligrams.) I know that sounds like a lot, so it’s important to remember that you don’t have to take this much; some people are more sensitive!

I, for example, used to take two or three scoops of pre-workout because I needed 400 to 500 milligrams of caffeine to feel a boost. Now, though, I stick with about 150 milligrams and get plenty energized off of that. These are anecdotes, of course; it’s important to take an amount of caffeine that works for you.

Tolerance can be an issue when it comes to caffeine. Over time (in as little as 15 days), we start to adapt to our daily caffeine dose and no longer get the same “boost.” This leads many people to up their dose—hence my previous excess pre-workout habit. However, even just a seven-day break increases your sensitivity, so it may be worth cutting back periodically in order to save some cash on pre-workout.

Read More: 5 Signs You Need A Break From Caffeine

To keep tolerance from increasing in the first place, try not to use caffeine every day [insert screaming emoji here]. I know this sounds impossible, but it will help keep your sensitivity in check. If you can’t make that happen, plan one week per month to swear off caffeine for the entire week. (It’ll probably be an awful week for you, but it will help keep tolerance at bay!)

Luckily for daily users, caffeine doesn’t have any long-term health concerns or complications for healthy people without underlying conditions. (If you have any kind of cardiovascular disease or metabolic disease, I’d check with your physician before taking it.)

However, caffeine can worsen symptoms of anxiety and nervousness in some people. So, if you’re prone to anxiety, caffeine might not be the best bet for you.

Caffeine Timing

To get the most workout benefit from caffeine, I’d recommend taking it about 30 to 60 minutes before training. (We typically see peak blood levels around 60 minutes after consumption.)

Since caffeine can actually impair insulin sensitivity and cause vasoconstriction (both of which affect recovery from training), I recommend against taking it after working out.

Lastly, I’d also avoid taking caffeine close to bedtime as it can impair sleep quality. Sleep is much more important than any supplement could ever be, so don’t mess with your sleep schedule!

The Bottom Line

All-in-all, caffeine is one of the most effective supplements for athletes looking for a performance boost. Though most of the research examines its acute effects, you’ll see greater gains if you consistently reap these benefits long-term.

Whether you go caffeine-free a few days a week or take a week off every month, do your best to maintain your sensitivity. And finally, though long-term use of caffeine is perfectly safe, double-check with your physician if you have any pre-existing conditions.

References & Further Reading

  1. Cardiovascular Research: Competition and redistribution among calcium transport systems in rabbit cardiac myocytes.
  2. Circulation Research: Calcium and excitation-contraction coupling in the heart.
  3. The Journal of Strength & Conditioning Research: Effect of caffeine on sport-specific endurance performance: a systematic review.
  4. Journal of Applied Physiology: Metabolic, catecholamine, and exercise performance responses to various doses of caffeine.
  5. Sports Medicine: Caffeine and exercise.
  6. Journal of the International Society of Sports Nutrition: Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis.
  7. PLoS One: Time course of tolerance to the performance benefits of caffeine.
  8. European Journal of Nutrition: Time course of tolerance to adverse effects associated with the ingestion of a moderate dose of caffeine.
  9. Nutrition Journal: Acute caffeine ingestion reduces insulin sensitivity in healthy subjects: a systematic review and meta-analysis.


Known as ‘The Muscle Ph.D.,’ Dr. Jacob Wilson has a knack for transforming challenging, complex concepts into understandable lessons that can support your body composition and health goals. A skeletal muscle physiologist and sports nutrition expert, Wilson is a leader in muscle sports nutrition. As the CEO of The Applied Science & Performance Institute and researches supplementation, nutrition, and their impact on muscle size, strength, and power.

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