Caffeine is the most widely consumed drug on the planet. Upwards of 80% of the adult population on the planet regularly consumes it. Many people don’t really realize it’s a drug, however due to the fact that it stimulates the central nervous system and can have an effect on mood it is classified that way. Caffeine has been touted as a performance enhancer and there’s an entire industry in energy drinks and pre-workout concoctions marketed to help give you that boost to help you perform at your best. There are even studies proving the efficacy of caffeine in moderate doses as a performance enhancer. While there’s no debate that caffeine can help boost energy, provide increases in performance and give you an overall increased feeling of well being there’s another side to this coin. In this article we’re going to analyze the benefits and the costs of caffeine.

Where Does Caffeine Come From?

Caffeine is a naturally occurring substance found in over 60 plants across the globe. It can be extracted from coffee beans, cacao beans, kola nuts, leaves and buds of tea, the leaves of yerba mate, and the bark of Yoco. There’s even “synthetic” caffeine created in laboratories from a substance called theobromine which is found in the cacao plant. Theobromine is the reason you can’t feed your dogs chocolate, it’s not necessarily a dangerous substance but your dogs just can’t effectively metabolize it. Caffeine’s one of the oldest drugs consumed on the planet and legend has it that Chinese Emperor Shen Nung first discovered the benefits of it on accident in 2437 BCE when the wind blew tea leaves into his boiling water. He was intrigued by the aroma and felt invigorated after drinking it, thus tea was born. Since then we’ve seen an absolute boom in caffein consumption across the planet. There’s a Starbucks on every corner across the country, soda’s being consumed at insane levels, just about every home has a coffee maker, there’s a thousand pre-workout concoctions on the shelves of your local GNC and even walking into a gas station can be nerve racking when staring at the nine thousand different options of energy drinks. It seems American’s can’t get enough of the drug and the average American consumes a little less than 200mg of caffeine on a daily basis. The average cup of coffee contains anywhere from 75-125mg of caffeine, sodas typically contain roughly 50mg of caffeine, and many energy drinks and pre-workout powders contain upwards of 250-300mg. These are absolutely dwarfed by Starbuck’s Venti coffees which contain upwards of 475mg of caffeine. For better or for worse it looks like caffeine is here to stay as far as most Americans are concerned.

Metabolism and Effects of Caffeine

So how does caffeine work? There’s an interesting cascade of events that takes place once that cup of coffee or energy drink passes your lips and enters into your digestive system. To understand how it works we’re going to take a look at adenosine’s role in the body. Adenosine is an inhibitory neurotransmitter in the brain (and throughout the body but since caffeine’s a CNS stimulant we’ll focus on the brain) that acts as somewhat of a depressant and helps to promote sleep and suppress arousal. Adenosine will bind to adenosine receptors in the brain and help to slow down impulses. These levels rise as the day gets longer, which is why we get more tired as the day drags on. So how does caffeine play into these receptors? Well, caffeine actually binds to these adenosine receptors and act as an antagonist and competes with the adenosine trying to bind to those receptors. When caffeine binds to these receptors they don’t “unlock” the receptors in the way adenosine would, they just prevent the unlocking from happening by blocking that adenosine from binding. Caffeine also binds to other receptors called A2A receptors, which helps with the release of dopamine and glutamate leading to the overall feeling of wellbeing after consuming it. This all probably sounds a bit confusing, so in layman’s terms let’s just say that caffeine basically turns off your body’s ability to get tired and promotes a feeling of well being.

In addition to the effects at the brain, caffeine also effects the kidneys, liver and lungs. The effects at the kidneys actually start in the brain in the pituitary gland. Caffeine acts as a diuretic by inhibiting antidiuretic hormone which keeps the kidneys from reabsorbing water and get rid of more water. This is one of the reasons you may feel the need to urinate more frequently after drinking a bunch of coffee. In the lungs it actually acts as a bronchodilator increasing lung function for a short period of time leading to better oxygen exchange. And in the liver it acts as a vasoconstrictor and increases the breakdown of glycogen for fuel utilization during competition/training. Caffeine affects a lot of bodily functions, some for the better and some for the worse and they all play into both detriments and enhancement of performance.

The Crash

We’ve all been there before. Maybe you didn’t get enough sleep the night before, maybe the night got away from you and you’re nursing a brutal hangover and have to get through the day, or maybe you’ve just had a hard week of training and need that boost to get through it so we pump ourselves full of caffeine. What tends to happen at the end of the day? We crash, and hard. Caffeine’s been binding to those adenosine receptors throughout the day not allowing that adenosine to do its job, and when the caffeine finally clears out BOOM, all that built up adenosine is free to bind to those receptors causing us to crash. Caffeine has a half life of about five hours, which means after five hours in your bloodstream the amount is halved. Say you drink a cup of strong coffee with 200mg of caffeine at 8am to start the day. Peak concentrations in your bloodstream will hit around 2 hours in, which is when we’re feeling a little jittery or restless/anxious. By 1pm that 200mg has now become around 100mg and you may start to feel a little drowsy. By 6pm you’ve now got around 50mg worth of caffeine in your bloodstream and you crash. Every 5 hours you’ll have about half as much caffeine in your bloodstream, causing the adenosine receptors to free up leading to us feeling a little drained all at once. This is an important effect of caffeine, as the highs we feel from it will inevitably be followed by the lows of the crash in the middle of the day and the higher the dosage, the harder the crash. That crash can be mitigated by ingesting more caffeine, however the more caffeine left in your system towards the end of the day, the more useless and hard your sleep becomes, leading to more caffeine and the cycle continues. Caffeine’s an addictive substance, the more we take the more our tolerance goes up so we need more and more. You ever had a headache after deciding to consume less caffeine? That’s actually a withdrawal symptom because your body has become accustomed to the effects of caffeine. 

Caffeine as a Performance Enhancer

There’s actually a good amount of literature on caffeine as a performance enhancer. It’s probably the second most studied performance enhancer just behind creatine and for good reason: because it’s widely used throughout the population and it actually works. The studies indicate that at dosages between 3-13mg per kilogram of bodyweight you’ll see the benefits of performance enhancement. So, if you’re a 150lb athlete you would divide your weight by 2.2 which yields your weight in kilos giving you roughly 68. You take this 68 and multiply it by 3-13 giving you a range of 204-886mg of caffeine. That sounds like a lot and that’s because it is. That’s anything from a strong cup of coffee up to 3-4 energy drinks worth of caffeine! When presented with these studies and this information it’s always a good idea to err on the side of caution and start (and stay) on the lower end of the spectrum. The athletes who respond to the higher end of caffeine intake are probably people who already consume good amounts of caffeine in their lives already, thus developing a bit of a tolerance that necessitates the need for more. Again, start on the lower end of the spectrum and see how you feel when performing. Caffeine is a central nervous stimulant that helps feelings of well-being, so it makes total sense that it can make the brain fire quicker and muscles fire faster leading to enhancement in performance.

In the heart caffeine acts as a vasodilator of the coronary arteries leading to an increase of blood flow to working muscles. In the lungs it increases air flow allowing for both more oxygen and carbon dioxide exchange. This can help ensure that the working muscles get a consistent flow of both oxygen and nutrients leading to better performance. You’ll run faster, jump higher and lift more and that sounds like a win, right? Well, there’s a down side when it comes to recovery and we’re going to explore that now.

Detriments of Caffeine Use in Sport

We’ve laid out the effects of caffeine and how they can be beneficial and talked about the effects of the crash but what are the downsides to this supplement when it comes to performance in sport? The detriments aren’t really felt during the heat of competition (outside of dehydration), they’re felt during the recovery process. Here’s just a few:

• Dehydration

• Increased breakdown of glycogen in the liver (sounds good, but it’s also bad)

• Habit forming

• Interruptions in sleep patterns

- Dehydration

Dehydration is of major concern with sports. We’ve all heard stories of athletes dying on the field of practice due to dehydration and the threat is real. On top of the life threatening possibilities from dehydration, there’s also a performance detriment. Performance suffers when we’re as little as 2% under hydrated, and when we hit 5% dehydration performance and power output drop as much as 30%! In sports, we simply cannot compete if our ability to perform drops by 30%, you’re completely out of the realm of competition at that point. In addition to that our bodies have an incredibly hard time staying in an anabolic state (a state of building muscle) when we’re as little as 3% under hydrated, and will switch to a catabolic state (breaking down muscle cells for fuel) making growth and recovery next to impossible.

- Liver Glycogen

Glycogen is out body’s stored form of carbohydrates. Think of glycogen being like fat cells, only they’re used to store sugars for energy as opposed to lipids. Glycogen is stored in both the muscles and in the liver. Breaking down glycogen stores in the liver and mobilizing those sugars for fuel sounds like a good thing right? Well yes and no. In the short term of competition it’s a great thing, however remember that the half life of caffeine is around 5 hours. When’s the last time you played a game that lasted 5 hours, probably never. That means this process continues following play when we need to be refueling for the next competition or training session. This process is going to halt you replenishing your glycogen stores, leading to decreased performance in your next game/training session.

- Habit Forming

Caffeine is an addictive substance. And not only on a physical level but it can be on a mental level as well. Have you ever met an athlete who is superstitious before? It’s fairly common. Some athletes have pregame rituals that are scheduled almost to the minute. Including a caffeinated beverage or pill prior to play can be something that ends up becoming part of this ritual, and it can lead to the caffeine becoming less effective and the athlete needing more over time. If you were someone who got in on the preworkout craze 15 years ago, you know exactly what I’m talking about. I think when it was all said and done I (and many others) may have been taking upwards of like 3 scoops of NO-XPLODE just to get up for a training session. The efficacy of the caffeine just decreases the more we use it, which can lead to athletes taking almost dangerous amounts.

- Interruptions in Sleep Patterns

We’ve talked about the five hour half life of caffeine earlier in this article, and that’s absolutely a detriment to recovery following competition/training. Let’s say you have a game at 7pm at night, and you decide to drink an energy with 300mg of caffeine before that game. The caffeine’s no doubt going to help you perform if you’re able to stay hydrated, but where does that leave your sleep? At midnight, you’ve still got around 150mg of caffeine (or a strong cup of coffee) running through your veins which is going to make it next to impossible to get any meaningful sleep. Losing that sleep is going to have an impact on your recovery, and readiness for the next day whether you’re training, taking an important test, have an important business presentation, or playing another game like during a tournament weekend. Caffeine taken at the wrong time, is definitely going to have detrimental effects on your sleep, and thus your ability to recover.

Wrapping it All Up

Caffeine is the most widely consumed drug on the planet providing many benefits including increased performance, but fails us when it comes to the recovery process. Caffeine can be used in competition and in training, but we need to make sure we’re taking steps to ensure we’re staying hydrated, not taking it at a time that’s going to disrupt our sleep, and making sure we’re not slowly increasing our intake as we make it part of ritual for training or competition. Is it for you? Only you can make that decision.