In my latest blog, I explored the origins of caffeine and how that substance became a staple in sports nutrition. Today, for this second and final blog post in collaboration with the Canadian Beverage Association, we will be talking about the real stuff. We will be discussing performance.
Because yes, your coffee can help you do much more than just lessen the struggle of getting your eyeballs open in the morning.
*Before we start, might I suggest a delightful cup of coffee as a pairing with the text below. We want to keep your mind awake while I throw some caffeinated knowledge at you.
Effects of caffeine on exercise performance
A little recap to begin with : caffeine is a molecule that is naturally occurring in the fruits, seeds and leaves of more over 60 plants.
In the early 1960s, a duo of English researchers were doing tests on themselves to study the impact of caffeine on performance. Today, hundreds of studies have investigated this substance. We now have a very distinct idea of how to use caffeine as a tool to maximize speed, endurance, power and energy.
An area where caffeine is particularly valuable is for endurance sports, or those that demand a sustained intensity for a long duration. Running, cycling and long-distance swimming are prime examples endurance efforts.
For these sports, caffeine consumption leads to a 2-4% improvement in endurance performance. I’m hearing you say « 2-4%? That’s nothing! » No offense, but you’re wrong J In Olympic events lasting between 45 seconds and 8 minutes, a less than 1% change in mean speed means the difference between a gold and bronze medal. Even better, in running events the speed difference between the bottom and top of the podium is less than 0.01%.
Endurance athletes know these facts. Lucky testers have observed this fascination with caffeine after analyzing more than 20 000 urine samples between 2004 and 2008 (a lovely summer job to say the least). Of the tested athletes, close to 75% were using caffeine before or during their sport, and especially during competition.
Power, strength and muscle endurance sports
Although most of the studies about caffeine in sports revolve around endurance performance, some power-driven sports do benefit from the substance as well. For example, three meta-analyses (statistical analyses of several studies) have found that caffeine consumption leads to 2-7% improvements in strength. This effect could enhance performance in sports such as powerlifting and weightlifting.
Interestingly, if a hobby of yours involves throwing objects as far away from you as you can, you will be pleased to learn that caffeine leads to a further shot put or medicine ball throw. Isn’t that splendid!
You want actual examples of the impact of caffeine on your favorite sports? Just ask and I shall deliver. OK, I will stop making up imaginary conversations and simply lay down the facts :
- Ice hockey → Caffeine increases physicality during a scrimmage. In other words, players hit harder when the gloves drop.
- Basketball → players jump higher, attempt and make more free throws.
- Soccer → players cover an increased distance, jump higher and are more accurate in their passing.
- Football → no improvement observed
- Cross-country skiing → athletes take less time to complete a set distance.
Effects of caffeine on cognitive performance
The intersection between physical and mental performance is where caffeine shines its brightest. Since the substance enhances alertness and decreases ratings of perceived exertion, physical efforts where an individual has to make quick decisions are really benefiting from caffeine consumption.
For example, it accelerates information processing in pentathlon athletes, increases the accuracy of passing for rugby and soccer players, as well as decreases reaction time in soldiers. The effect is even more notable in sleep deprived individuals.
How does it work?
Let’s dive into neurology a little in order to better understand, One of the body’s neurotransmitters, adenosine, decreases the concentration of other neurotransmitters, such as serotonin, dopamine, acetylcholine, glutamate and norepinephrine. This has a calming effect.
The molecular structure of caffeine is strikingly similar to that of adenosine. It is thus capable of binding to adenosine’s receptors and prevent adenosine’s neuromodulating effect.
In simple terms, it’s pretty much the same as what happens in the movie « The Pretty One » when Laurel (played by Zoe Kazan) takes the place of her twin sister Audrey (also played by Zoe Kazan) and lives her sister’s life as if it were hers. If you have not yet watched this movie, it’s okay. Let’s just say this whole metaphor is better than the movie itself…
All that to say that after binding on a receptor that is technically adenosine’s, caffeine increases the concentration of the neurotransmitters listed above, resulting in positive effects on vigilance, mood, alertness and focus.
What is the maximum recommended amount of caffeine?
According to Health Canada, the maximal caffeine dosage is 400 mg per day. For your information, a cup of home-brewed coffee contains about 90 mg. In order to reach this dosage with widely available beverages, you would have to drink the following :
- 14 green teas
- 5 standard cola bottles
- 5 small energy drinks
- 5 home brewed coffees
- 5 store bought coffees
Ingesting more than this quantity may lead to side effects such as headaches, insomnia or nervousness.
Fun fact : we are told that coffee dehydrates, but this is actually false. Caffeine has a small diuretic effect, which means it increases urine production. However, in 98.8% of cases, we ingest caffeine in the form of a beverage such as coffee, tea, and soft drinks. The amount of liquid we drink therefore hydrates us more than the caffeine inside it dehydrates us!
Thus, caffeine consumption is mostly safe, but if side effects occur, pay attention to the amount you ingest in a normal day.
Where to find caffeine?
Apart from the coffee you drink every day (or shall I say your coffeeS), sports nutrition opens the door to other ways to ingest caffeine. For instance, we find it in chewing gum, tablets, mouth rinses, aerosols and other inspired powders, gels, and bars. We also find it in the ever-popular pre-workout supplements and energy drinks.
Among these options, caffeine ingested as coffee, chewing gum or tablets shows the most widely studied positive effects on performance. To my surprise, a myriad of studies about pre-workout supplements and energy drinks shows that these products too, when used under specific circumstances, succeed in improving exercise performance. Others, although quite promising, lack consistent results to be recommended.
What dosage helps improve performance?
Caffeine leads to an improved performance when consumed in doses of 3-6 mg per kilogram of body mass, 60 minutes before an effort. For example, a 70 kg athlete should ingest between 210 and 420 mg of caffeine. The following products could be used :
- 2-4 home brewed coffees
- 2-4 tablets of 100 mg each (ex. « Wake Ups »)
- 1-4 caffeine chewing gums (according to the dosage labeled on the product)
N.B. The absorption of caffeine in chewing gum happens faster than in coffee or tablets. It is therefore recommended to ingest it 10 minutes before an effort instead of the usual 60 minutes. Also, since caffeine in chewing gum is absorbed both by the buccal mucosa and in the digestive tract, it can be consumed during an effort and still be fully absorbed, which is not the case for other products.
Since commercial products don’t contain the same amount of caffeine from one brand to the other, it is very important to double check the amount of total caffeine detailed on the label and the dose that you use.
Ingesting a product without knowing the caffeine dosage is not recommended. This is because above a certain amount, caffeine starts to hinder performance instead of improving it. Specifically, consumption of 9 mg/kg or more is linked to an increased risk of side effects such as heart palpitations, anxiety, headaches and impaired sleep quality.
If doping is one of your concerns, the World Anti-Doping Agency (WADA) allows caffeine consumption since it lifted the ban in 2004. The agency still monitors the substance, but to reach the upper recommended limit, you would have to ingest the equivalent of 10 mg of caffeine per kilogram of body mass for several hours, which is more than triple the amount reported to improve performance. Such a high amount would likely lead to severe side effects and a very poor performance anyway, so you’re safe on that front.
In conclusion, caffeine is quite safe. When used in accordance with the recommended dosage (3-6 mg/kg body weight) and in optimal timing (~60 minutes before effort), it can lead to a sizable improvement in performance for certain sports.
As always, a sports nutritionist can help you make the most out of your food and supplements. If you decide to try caffeine, I recommend testing it during training before using it for a competition.
On this note, I’m wondering : will you try caffeine for your sport?