Most people enjoy sipping a cup of coffee first thing in the morning and, often, later in the day as well. Studies suggest that coffee has health benefits and is linked with a lower risk of some health problems, including type 2 diabetes, Parkinson’s disease, heart disease, and liver disease. Plus, coffee is the number one source of antioxidants in the American diet. But, coffee also has benefits for some types of exercise and sports performance, enough that it’s classified as an ergogenic aid.
How can coffee boost sports performance? Studies show that caffeine enhances performance for sub-maximal endurance exercise, such as running or cycling at a moderate intensity. According to some research, it also boosts performance during high-intensity exercise, partially by reducing the perception of how hard the exertion feels. But, what role does caffeine play in enhancing muscle strength? Can sipping coffee before a strength workout improve your performance?
Caffeine, Coffee, and Strength Training
The evidence that caffeine enhances muscle strength is weaker than the evidence that it boosts exercise endurance. Yet, a 2018 meta-analysis of 10 studies found that caffeine may have modest benefits for strength. In the study, a caffeine supplement improved upper body strength (as measured by one-rep max) and muscle power (as measured by vertical jump). Another review of 34 studies published in Medicine and Science in Sports and Exercise showed caffeine consumption was linked with a small boost in strength, primarily in the knee extensors. Maximal voluntary contraction was not increased significantly in other muscle groups.
Some research shows modest benefits and others show little or no enhancements of strength with consumption of caffeine. One encouraging study found that caffeine intake boosted strength for barbell squats by 3%. Another study found caffeine enhances upper body strength. Yet, other research shows no significant benefits. In terms of the ability to generate power, results are also mixed. Some show modest improvements in vertical jump height while others show non-significant improvements in jump height after consuming caffeine.
All in all, the impact of caffeine on muscle strength and power appears to be modest. But, interestingly, one study found that consuming caffeine compensates for daily variations in muscle strength. Do you typically do strength training in the morning? That’s the time of day when your muscles are the least strong. In fact, muscle strength peaks in the late afternoon or early evening. The ideal time to strength train, based on research, is 6:00 P.M. at night when your muscles are near their peak of strength. But, what if that doesn’t suit your schedule? Caffeine may give you an edge if you train early in the day.
How do we know this? A study published in PLOS One in 2012 showed that caffeine compensates for the strength differential between morning and evening. Researchers found that resistance-trained participants who took a caffeine supplement containing 250 to 350 milligrams of caffeine before a morning workout, displayed similar strength as when they trained in the evening. So, caffeine seems to compensate for diurnal variations in strength.
Why is this important? If you train when you’re strongest, you’ll typically do a higher quality workout and be able to hit your muscles harder before fatiguing. This can lead to greater gains in muscle strength and size. A 12-ounce brewed cup of coffee has around 120 milligrams of caffeine. So, drinking 2 cups of coffee before a workout is enough to offer benefits. Keep in mind that the caffeine content of coffee can vary widely. For example, a 12-ounce blonde roast at Starbucks has 270 milligrams of caffeine. It’s easy to see why they use supplements in studies! Otherwise, it would be hard to standardize.
Caffeine Boosts Exercise Endurance
Studies showing caffeine boosts exercise endurance are more consistent than those focusing on strength and power. For example, one study found that participants who cycled at an intensity of 60% of V02 max for 60 minutes reported a lower rate of perceived exertion when they drank caffeinated coffee as opposed to decaf. Other studies show that caffeine boosts exercise endurance in a dose-dependent fashion. One way it does it is by reducing the perception of effort. In other words, an endurance workout feels easier with caffeine on board and you’re able to exercise longer at a sub-maximal intensity as a result.
How much caffeine do you need to get benefits? Studies suggest that anywhere from 2.5 milligrams of caffeine per kilogram of body weight to 5 milligrams per kilogram of body weight is sufficient. So, between 2 to 4 cups of brewed coffee, on average. In general, 400 milligrams of caffeine daily is considered safe for the average person.
The Bottom Line
Caffeine may modestly boost strength and power, mainly for large muscle groups in the lower body. It also may compensate for the strength differential between morning and evening. The optimal dose is in the 200 milligrams to 400-milligram range. But, keep in mind, some people have side effects such as anxiety, insomnia, or tremors, at the higher end of this range. You also have to consider the caffeine you get from other sources, such as tea, chocolate, medications, soft drinks, etc. It adds up over the course of the day. But, hopefully, you aren’t getting most of your caffeine from soft drinks!
Also, caffeine isn’t for everyone. Around 25% of the population metabolizes it slowly and are at higher risk of side effects. So, listen to your body. If you do well with caffeine, it may offer some benefits when you train, particularly for endurance exercise. So, sip coffee in the morning if it makes you feel good and you don’t experience unpleasant side effects. It might boost your performance when you train.
References:
J Int Soc Sports Nutr. 2018; 15: 11.
Fitness RX. August 2012. “Caffeine Eliminates Daily Variations in Strength”
Medicine and Science in Sports and Exercise 42(7):1375-87 · December 2009.
PLOS One. “Caffeine Ingestion Reverses the Circadian Rhythm Effects on Neuromuscular Performance in Highly Resistance-Trained Men” April 4, 2012.
Percept Mot Skills. 2007 Dec;105(3 Pt 2):1109-16.
EFSA Journal 2015;13(5):4102.
Related Articles By Cathe:
Why Caffeine after a Workout Has Potential Benefits
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Why Energy Drinks and Exercise Don’t Mix
Sports Drinks and Hydration Beverages: What Are the Different Types and Do You Really Need Them?
Related Cathe Friedrich Workout DVDs:
STS Strength 90 Day Workout Program
All of Cathe’s Strength & Toning Workout DVDs
Total Body Workouts
Lower Body Workouts
Upper Body Workouts
