How Caffeine Boosts Exercise Performance

Caffeine not only gets us going in the morning. Find out what makes caffeine an effective exercise booster and how to use it to up your gym game.

But first, coffee. If you’re like 90 percent of Americans, you rely on caffeine to get you through the day (1). This widely accepted stimulant may offer energizing benefits beyond battling the morning sleepies. 

Grabbing a cup of joe before you go -- to the gym or for a run -- can help boost exercise performance and endurance. But this all depends whether you’re a daily indulger and the type of exercise you’re engaging in.

What is caffeine?

Caffeine is the most popular and commonly used psychoactive drug in the world, meaning that it affects the way we think (2). Caffeine is a mild stimulant of the central nervous system (brain and spinal cord), which speeds up the messaging between the brain and body. This is why it can offer energy, mood improvement and sharpness.  

Caffeine naturally comes from the plants used to make coffee, tea, and chocolate. It’s also artificially added to foods and beverages such as energy drinks, soda, and also comes in the form of supplements

The amount of caffeine in different foods and products varies greatly depending on where the plants (such as coffee beans and tea leaves) were grown as well as how the food or beverage is manufactured and prepared. 

Common caffeinated products:

  • 12 fluid oz (350 mL) soda: 30-40 mg
  • 8 fluid oz (235 mL) cup green or black tea: 30-50 mg 
  • 8 fluid oz (235 mL) cup of coffee: 80-100 mg 
  • 8 fluid oz (235 mL) of energy drink: 40-250 mg 
  • 1 oz (28 g) dark chocolate: 15 mg (3)

Caffeine for fitness 

Moderate caffeine consumption (three to four cups of coffee per day) has been linked with improved fitness performance and endurance (4). Caffeine is particularly effective for fitness when it's not consumed on a regular basis. 

Caffeine and endurance training

Endurance training is aerobic exercise such as running, swimming, climbing, or cycling. Caffeine has been shown to be an ergogenic aid, or a substance that can enhance energy production and improve recovery, when it's taken before and/or during exercise at moderate amounts (5). It has been shown to increase speed or power in race settings (6). 

People who aren’t used to consuming caffeine will most likely see a better benefit than those who have it on a regular basis (7). Benefits have been suggested to be greater when caffeine is avoided for a week before an event. So if you’re not regularly consuming caffeine, or if you take a break from it, then you may be getting a better boost. 

Caffeine and strength 

Research seems consistent when it comes to the benefit of caffeine on physical performance for endurance exercises. Caffeine seems to enhance muscular endurance but the effects on maximal muscle strength and power remain unclear (8). 

Some research suggests that caffeine can help reduce muscle pain, therefore potentially encouraging you to workout longer and harder. High intensity cyclers who ingested caffeine reported less muscle pain than in a group who habitually had low amounts of caffeine (9). 

Caffeine: how much is too much?

According to the Food and Drug Administration (FDA) caffeine can be part of a healthy diet for most people, but too much of it may pose a danger to health (3). The FDA estimates that toxic effects of caffeine such as seizures, can happen when about 1,200 mg (about 12 cups of coffee or 0.15 tablespoons of pure caffeine) are consumed (3). 


According to the British Medical Journal analysis, drinking three to four cups per day is usually safe for most people and even associated with some potential health benefits but it’s important to keep in mind that everyone responds to caffeine differently (10). 

Caffeine sensitivity refers to how much of an effect caffeine has on our bodies. Certain conditions and medications can make us more sensitive to its effects. If you’re sensitive to caffeine, you may experience anxiety, shakes, headaches, digestive issues, and insomnia after having caffeine. If this is the case - the consumption of caffeine is better to be limited.

Sleep Interruption 

Caffeine has a half-life of roughly five to six hours. Meaning that if you drink a coffee at 4 p.m., you’ll still have caffeine in your system by 10 p.m. This can be problematic when it comes to trying to fall asleep. Aim to avoid caffeine-containing products later in the evening. As an interrupted sleep can impact health and fitness performance. 


Like any drug, the body and brain can develop tolerance to caffeine. So over time, it will stop working in terms of the same energy boost and fitness advantage. Just like anything, it’s important to practice moderation. 

If you’re used to caffeine and want to cut back, it’s best to do so gradually. That’s because if you cut cold turkey, you may experience unpleasant withdrawal symptoms such as headaches, anxiety, or nervousness. Try starting by switching half of your caffeinated beverages to decaf. 

Final sips

Caffeine in moderation may be helpful for boosting athletic performance, especially when it comes to endurance activities. The greatest benefits have been seen when caffeine is avoided or limited, then used for particular athletic events. 

Keep in mind that your body is unique and may respond differently to the effects of caffeine. And remember that what you put in your coffee, tea, can impact fitness and weight loss efforts. 

Looking for other healthy alternatives to milk to add to your coffee? Check these delicious milk alternatives:

3 alternative milks and their pros and cons

10 references (hide)

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