Caffeine: How it Works For and Against Your Performance

Caffeine: How it Works For and Against Your Performance

It’s 4:45 a.m. and the alarm clock is forcing you from deep and peaceful slumber to the reality of a 5:30 a.m. swim practice. Or, it’s 8 a.m. and you’re rushing out the door to get to a busy work morning followed by a lunch interval run. Maybe it’s 2 p.m. and the afternoon heavy eyelids and fuzzy brain are taking control of your ability to be productive; work needs to be done before the escape to an evening ride. For many busy athletes, the solution and complement to all of these situations is delivered simply– hot, cold or somewhere in between– in a mug, a glass or maybe whipped into a recovery smoothie. What is it? Coffee.

According to a recent study,“Coffee drinks are immensely popular in the United States, as coffee consumption represents 75 percent of all caffeine absorbed in this country.” According to the Harvard School of Public Health, 54 percent of Americans over the age of 18 consume coffee at an average of 3.1 cups every day, and the U.S. spends 40 billion dollars a year on coffee. While no studies on the athlete population’s consumption habits were readily available, it seems likely that it would be greater than that of the general population due to the simple fact athletes are often cutting sleep and looking for ways to generate enough energy to get through busy days.

There aren’t warning signs at coffee shops reminding you of the side effects you may experience when drinking coffee. Like any drug though, coffee has plenty. This drink is made from the seeds of the berry of the Coffea plant and is consumed worldwide, so it is easy to infer from this that relying on coffee is a good decision. Is it the wonder drug that keeps the planet spinning and your workouts rolling off without a hitch? Can you imbibe that morning infusion without concern? What’s better, regular systematic consumption of coffee or keeping away from it enough to avoid habituation? Finally, is coffee the ticket to making you a better athlete? Read on.

The large take away from the literature is that you are probably not doing yourself any physical harm by consuming coffee. More likely, moderate consumption can be good for you. A study published in the New England Journal of Medicine looked at hundreds of thousands of men and women and the bottom line was that people who drank coffee lived longer than those who did not. Interestingly, the same health benefits were demonstrated in Japan with green tea consumption.1  Note that to achieve the health benefits, the caffeine may be removed from the coffee or tea itself, meaning the longevity benefits may have come from the coffee and tea plants themselves and not specifically caffeine.

Knowing that you are not harming yourself is good, but consumption of caffeine does have some deleterious effects, many of them based on your own physiology.2 Some individuals experience headaches, increased heart rate, tremors or shakes and even an impairment in performance. Caffeine is also addictive and changes in brain functioning have been studied in conjunction with regular consumption. According to the newest edition of the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) excessive intake can lead to “caffeine intoxication” which is followed with a newer diagnostic of caffeine withdrawal whose symptoms include fatigue, headache and difficulty focusing. That means caffeine withdrawal is now an official mental disorder. The symptoms of withdrawal are highly unpleasant. The manual notes that many people may drink coffee not only for caffeine but also because of the pleasurable aroma and taste of coffee as well as the environment that usually accompanies coffee consumption. You become addicted to the process, not just the caffeine.

There is plenty of evidence that caffeine enhances endurance and provides benefits for the athlete. “The most likely mechanism is that central nervous system effects provide fatigue resistance or a masking of the perception of effort.”3 Anyone who has added in a caffeinated gel or fuel source in an IRONMAN can testify to the uplifting effects. Recent studies confirm that modest levels of intake are best, and a range of 1-3mg/kg BM or 70-150 .mg caffeine when it is taken before or during exercise. In the case of caffeine, more is not more, so noting the recommended dosages and sticking in that range offers the best chance of performance benefits without the negative side effects. Key to note once again is that the effects of caffeine clearly elicit different responses based on the individual. Since these may include impairment of athletic performance and general functioning through nervousness, loss of sleep and stomach upset, it’s important to test your own limits and find out what works for you. In referencing caffeine intake related to sports performance, coffee is not recommended as an ergogenic aid quite plainly because the amount of caffeine in a given amount of coffee varies widely and isn’t reliable in dosing.

Finally, does the frequent coffee drinker lose some of the benefits of caffeine consumption related to athletic performance and is it necessary to withdraw from usage to facilitate improved response? Keep in mind here the research is mixed and more is needed, but most recently studies showed that regular caffeine users would be better advised to continue on their usage schedules than risk the negative consequences of withdrawal, such as headaches and fatigue. There is some evidence that the positive influence of caffeine on performance is actually reduced when habituation is not present as there may be a higher risk of the negative effects such as heart rate increase, tremors and irritability. That said, keeping caffeine consumption moderate and as a part of a balanced sports nutrition plan is ideal.

As you can see, coffee consumption is okay for most people. The complexity lies in the individual, the situation and the habit forming nature. Recognizing that coffee is not a substitute for sleep on a regular basis and also being aware of the potential side effects of withdrawal is important for every user. Choosing to consume coffee and caffeine products specifically as an ergogenic aid should be thoroughly tested in training.

Carrie McCusker specializes in athlete performance at all levels. While she has spent the majority of her life as a competitive elite athlete she is also an experienced educator and coach with an MS in education and extensive training in the implementation of science based coaching with a focus on meeting the needs of each individual athlete. She can be reached at or see details at or

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