We know that nutrition plays an essential role in peak athletic performance, but what does that mean when it comes to the best drinks for sport? Registered dietitian Wendi Irlbeck looks at the role of hydration in athletic success, as well as the best drinks to support fluid status, muscle growth, and overall exercise recovery pre-, during, and post-workout.
Caffeine is a very interesting substance from a sports performance perspective; it has the potential to enhance performance significantly, and yet is completely legal to use during training and competition. I’ve written widely about caffeine before, both for SimpliFaster and academically. Based on the current academic research, you might think that we know all there is to know about the use of caffeine in sport. There are, however, still many important areas where we could better understand the nuances associated with caffeine use to enhance performance.
One area ripe for further exploration is the best method to consume caffeine. In a recent umbrella review article on caffeine, my coauthors and I concluded that caffeine exerts clear performance-enhancing effects on sporting performance based on the evidence to date. And the amount of caffeine present in 1-2 cups of coffee was sufficient to enhance performance.
Broadly speaking, this is true. A “standard cup of coffee” (more on this later) generally contains 100 mg of caffeine. For most people, two cups of coffee (200 mg of caffeine) equals 2.5 mg of caffeine per kilogram of bodyweight (mg/kg)—enough to provide some performance benefit. Of course, we already know that coffee may improve performance.
Drinking coffee is the most widely used way of consuming caffeine by nonathletes, with an estimated 2.25 billion cups of coffee consumed daily across the globe. Humans consume coffee for a variety of reasons, commonly including its positive effects on alertness and concentration, which are especially pronounced when we’re sleep-deprived. These benefits are derived largely from the caffeine contained in coffee. Athletes, who widely use caffeine to enhance performance, often drink coffee to consume their caffeine before training and competition.
But while coffee contains caffeine, it also contains a variety of other chemicals, including chlorogenic acids, caffeic acid, and ferulic acid. These chemicals may affect athletic performance in other ways by further enhancing caffeine’s ergogenic effects or reducing them. It’s important to keep in mind that coffee and caffeine are not interchangeable terms even though many people treat them as such.
And while we’re clear that caffeine enhances performance, we’re less clear as to whether coffee does, which I recently explored in a review paper with my co-author Jozo Grgic. We sought to answer some key questions, including “Does caffeinated coffee improve exercise performance?” and “Is this performance enhancement similar to that of stand-alone caffeine?”
Does Caffeinated Coffee Enhance Exercise Performance?
A variety of studies have explored whether caffeinated coffee improves exercise performance, often with mixed results. For example, an early study showed that 3 grams of instant coffee dissolved in water improved 1500m running performance. A more recent study found similar results where coffee provided 3 mg/kg of caffeine and enhanced one-mile running performance. Similarly, a study on cyclists found that 5 mg/kg of caffeine in coffee improved performance to a greater extent than decaffeinated coffee.
However, not all studies support caffeinated coffee’s performance-enhancing effect. For example, a 1998 study found no difference between coffee (providing 4.45 mg/kg of caffeine) and decaffeinated coffee on running performance, as did a more recent study looking at the effects of coffee containing 5.5 mg/kg of caffeine on 800 m running performance. In terms of resistance training, a 2016 study reported no difference in terms of muscular endurance between caffeinated and decaffeinated coffee, while Clarke and colleagues found coffee did not affect repeated sprint cycling performance.Coffee has the potential to improve performance when it provides a typical performance-enhancing dose of caffeine, says @craig100m. Click To Tweet
All in all, this suggests that caffeinated coffee has the potential to enhance aerobic endurance performance, but not strength or sprint performance. This essentially mirrors the general findings from the research on caffeine. There is a clear ergogenic effect on endurance performance, with unclear (or at least inconsistent) benefits on strength and speed performance. While there is very limited research on the performance effects of caffeinated coffee, coffee appears to have the potential to improve performance when it provides a typical performance-enhancing dose of caffeine.
Does Coffee Improve Performance to the Same Extent as Caffeine?
This question is surprisingly difficult to answer because very few studies have attempted to explore it. When it comes to aerobic performance, there are mixed results: one study found that caffeine was more effective than caffeinated coffee while another reported no difference between the two. Again, when it comes to resistance training performance, the majority of studies comparing caffeine and coffee report no performance-enhancing effects of either. Again, this means we need more research to understand better what differences—if any—exist between caffeine and coffee for enhancing sport performance.
What Does This Mean from a Practical Standpoint?
With limited evidence available, we can tentatively state there is no difference in performance enhancement between caffeine and coffee, providing there’s an equal dose of caffeine. Caffeine is most reliably ergogenic at doses of 3-6 mg/kg (although it can enhance performance at lower doses). For caffeine to enhance performance, we need to consume 3-6 mg/kg.
Here is where we reach our first practical hurdle—this potentially means we have to drink a lot of coffee. In one of the studies detailed above, the subjects drank 600ml of coffee. In another study, participants had 5 cups of coffee of 200ml each, for a total of one liter. If an average cup of coffee contains 100 mg of caffeine, two cups will provide around 210 mg of caffeine for a 70-kg athlete—enough to provide an ergogenic effect.
For larger athletes, this adds up quickly. A 120-kg male, for example, would need four cups of coffee. Regular caffeine users may require even more caffeine pre-competition. It would not be surprising for a larger athlete to have to drink 6-7 cups of coffee before a competition, which could equate to well over a liter of fluid. This amount could lead to feelings of fullness and discomfort during exercise as well as add 1 kg of weight to the athlete, which may harm performance in and of itself.The amount of caffeine in a cup of coffee varies widely between brands & within the same brand, so it's hard to get a specific dose, says @craig100m. Click To Tweet
Another complicating factor is that the amount of caffeine in a cup of coffee differs both between brands and within the same brand across time. The differences make it very difficult to know how much caffeine you’re getting from your cup of coffee. For example, a 2007 study determined the level of caffeine in 97 different samples of espresso from the Gold Coast, finding the caffeine content ranged from 25 to 214 mg per coffee. In a follow-up study, the same research group purchased the same coffee from the same outlet at different times and again found the caffeine content ranged from as much as 81 to 189 mg within the same coffee brand.
Making coffee at home fares no better. A recent study discovered that the caffeine concentration of Nespresso coffee pods ranged from 19 to 147 mg per serving. Consequently, it’s often unclear just how much caffeine we consume when drinking coffee. And it becomes very challenging to achieve a specific caffeine target dose, increasing the risk of over- and under-dosing caffeine, which may harm performance and offer additional side effects.
A final practical concern is that coffee is often consumed hot, which creates two issues:
- It has to be transported to the training or competition venue in a container that maintains its heat.
- The consumption of hot liquids before exercise may affect thermoregulatory control; in hot or humid conditions, the increase in body temperature from drinking hot liquid may reduce performance.
Current research leads us to a tentative conclusion that coffee has potential to enhance performance as long as it delivers an ergogenic dose of caffeine, which typically falls in the 3 mg/kg range. Note that this value may be much higher or lower depending on individual variation and previous caffeine behaviors. Caffeinated coffee also may be as effective as caffeine consumed by itself, although only when the caffeine doses match.
If you want to use coffee as the means of consuming caffeine pre-exercise—perhaps you like the taste of coffee—drinking it around 60 minutes before exercise should enhance performance, especially in endurance exercise.
Depending on the caffeine dose required to improve performance, you might have to consume a lot of coffee. And given the variation in caffeine concentrations within servings of coffee, you might get more or less caffeine than you initially planned. Finally, coffee is consumed hot typically, which may affect body temperature control during exercise.Before competition, I suggest athletes drink caffeinated sports drinks or take caffeine tablets, says @craig100m. Click To Tweet
Before competition, I suggest athletes don’t use coffee as their caffeine source but instead drink caffeinated sports drinks or take caffeine tablets. For recreational athletes and athletes in a less serious block of training, 2-3 cups of coffee 60 minutes before exercise likely will enhance performance.