Most of us are intimately familiar with the boost that a good ol’ cup of joe gives us first thing in the morning, but it can also be a useful tool before your workout to improve performance, delay fatigue, and enhance the effects of your workout. For this reason, many workout supplements include caffeine as an ingredient, and it is a monitored substance by the International Olympic Committee. Caffeine affects almost every system in our body, but its impact on mood, alertness, metabolism, and exercise performance are produced by some pretty specific physiological interactions. Here’s how caffeine works its magic on your workout:
1. It mobilizes fat from fat tissues.
Caffeine can improve physical performance by 11 to 12 percent, on average. Caffeine increases our blood levels of the hormone epinephrine, aka adrenaline. The epinephrine travels through the blood to the fat tissues and sends signals to break down the fats and release them as free fatty acids into the blood, where they can then be used as fuel. More fuel = a stronger, longer workout. This reaction especially enhances endurance exercise.
2. It delays perceived muscle pain.
The effect of caffeine on strength training is less well-documented, although recent studies have shown that ingesting caffeine prior to weight training increases the amount of weight lifted, as well as number of reps. This is possibly due to caffeine’s ability to blunt pain responses so that your muscles don't get fatigued as quickly during resistance training.
3. It improves energy and mood.
By blocking the neurotransmitter adenosine, caffeine ups the firing of neurons and the release of neurotransmitters, including dopamine and norepinephrine. This affects myriad brain functions: memory, mood, vigilance, energy levels, reaction times, and even general cognitive function. And we all know how hard it is to pump ourselves up for a good workout when we’re in a bad mood, right?
4. It increases calories burned.
This one doesn’t directly affect your workout, but it goes hand in hand with the results of your workout. Ingesting caffeine before a workout can actually increase the number of calories you burn from the workout. A study published in the International Journal of Sport Nutrition and Exercise Metabolism found that trained athletes who took in caffeine pre-exercise burned about 15 percent more calories for three hours post-exercise, compared to those who took a placebo. Caffeine also blunts your appetite, which could also aid in weight loss.
5. It increases metabolism.
It turns out that caffeine can also affect how well your body burns calories when you’re not even exercising. Studies show that caffeine can increase our resting metabolic rate (how many calories we burn when we’re doing nothing) by 3 to 11 percent, with larger doses having an even bigger effect. But here's the rub: The effect isn’t equal for everyone. The increase in fat-burning in lean people is as high as 29 percent while in obese individuals the increase is about 10 percent. The effect also appears to diminish with age.
So what does this all mean? Should you down 10 shots of espresso before each workout? The answer is no. Yes, caffeine may help you push just a little bit harder during your workouts, resulting in improvements in muscle strength and endurance. But there are also side effects of drinking too much caffeine, including anxiety, jitters, inability to focus, gastrointestinal unrest, insomnia, irritability, and, with higher doses, the risk of heart arrhythmias and mild hallucinations. Obviously, any of these could have a negative impact on your race or workout!
The optimal dosage of caffeine to enhance your workout is 3 to 9 mg of caffeine per kg of body weight. To put that in context, a tiny, 6-ounce cup of coffee contains 60 to 180 mg of caffeine, and a 1.5-ounce shot of espresso contains 70 to 80 mg. The optimal time to consume that coffee seems to be about an hour before your workout.
It’s also important to keep in mind that your body adapts to the effects of caffeine in the long term, so in order for these effects to remain effective, you should cycle your caffeine intake about every two weeks.
Give it a try, and let us know in the comments below how caffeine has affected your workout!