The Intelligent Use of Caffeine in Exercise and Sport
We are a nation of stimulant junkies….and I love it. I have always thought that if you are going to be addicted to something, it might as well be stimulating. Better to enhance awareness (and thus existence) than blunt it or alter it. But, then again, the author is the guy who, when asked to test amphetamine for Naval Aviation, threw down two tabs, grabbed a cup coffee, and hit the gym. THAT was AWESOME.
Coffee is the peace pipe of America, the nectar of the gods, and is shared around the home, office, and restaurant on a daily basis. Heck, we even named a table in our living room after it.
Caffeine is ubiquitous in our society and found in coffee, tea, cola, chocolate, among many other products. It’s positive effects on focus and mood have been known for centuries and it has been actively researched for decades. It was removed from the World Anti-doping Agency’s list of restricted or banned substances in 2004. The fact that it was originally banned is a testament to a definite performance enhancing effect. Apparently 2004 was a bad year for neo-puritans.
It’s popularity has soared over the last two decades and it is now a prominent component of many sports drinks, sports gels, energy drinks, and even chewing gum. As popular and widespread as it is, we should take a moment to examine its effects, both good and bad, on our bodies.
How does caffeine exert it’s effects?
Caffeine works via multiple mechanisms in the body.
- It increases Epinephrine (Adrenaline) which serves to both increase focus and increase glycolytic flux (more glucose to working muscles).
- It inhibits the enzyme phosphodiesterase (which increases cAMP intracellularly) leading to greater lipolysis as well as a greater increase in calcium release from the sarcoplasmic reticulum (calcium is essential for muscle contraction). * For #1 and #2 most of the studies done in the lab were with doses that would be toxic in an actual human so this is not likely to carry over to the actual effects seen in exercise and sport
- Current thought in examining the ergogenic effects of caffeine is that the primary mechanism is the ability to act as an adenosine receptor antagonist (it blocks the action of adenosine by blocking the receptor). This allows it to induce effects on the nervous system, to reduce pain and how we perceive our fatigue, and improve muscle recruitment as well as excitation-contraction coupling. Blunting pain may mitigate fatigue by extending time to exhaustion or time to quitting due to pain-mediated failure. Don’t be a quitter.
Caffeine is similar in structure to adenosine. Since adenosine is a vasodilator, blocking it via caffeine leads to vasoconstriction (explains the use of caffeine in vascular headaches such as migraines). In the brain, increased adenosine levels lead to enhanced pain perception, sleep inducement, reduced arousal, and depressed locomotor activity. I hate all those things. Since caffeine so effectively blocks the adenosine receptor, all of these effects are counteracted. With 4 different types of adenosine receptors in the brain many effects are yet to be fully explored.
Note that “pain” reduces the ability for a forceful muscle contraction. Thus blocking these pain pathways would lead to more forceful contractions. Caffeine combined with other analgesics reduces pain better than single analgesics alone and caffeine has even been shown to attenuate DOMS and force loss following exercise.
Are there any side effects that are concerning?
High doses of caffeine used in research studies, or seen in my Emergency Department in overdose situations, have predictable effects. The most common side effects are an elevated heart rate (HR) and blood pressure (BP), nausea (occasionally vomiting), nervousness, mental confusion, and disturbed sleep. Blood testing would show a doubling of catecholamine levels (adrenaline), higher blood lactate levels, and an increase in fatty acids
While most research has been on moderate to high doses (5-13 mg/kg), lower doses have now been shown to be beneficial (3mg/kg) at 200 mg in an adult.
-do not alter the peripheral whole body response to exercise
-improve vigilance, alertness, and mood
-have fewer side effects
When doses were reduced from high to moderate levels the performance enhancement remained and the side effects diminished but were still present.
The lower dose of 3 mg/kg produced an ergogenic effect without side effects and with no changes in HR, catecholamines, free fatty acids, etc. suggesting that the primary effect of caffeine was via the central nervous system or brain.
How does caffeine benefit us in exercise and sport?
The effect on endurance performance is well founded and the amount of literature I found was exhaustive. I will not bore you with that here. Let’s take a look at what is known about caffeine and human performance to see if it will indeed help us in the gym to lift heavier weights, get stronger, and gain lean body mass.
Recently several researchers collaborated on a systematic review of caffeine use as an ergogenic aid in anaerobic exercise, focusing on bouts of activity ranging from 4 to 180 seconds. The Wingate test (sprint cycling power) is a widely accepted measure of power output and anaerobic capacity. Most studies that have used this test in untrained subjects have failed to show an ergogenic effect of caffeine use but there are problems comparing the performance of untrained subjects versus trained subjects due to the rapid adaptation to exercise among a host of other factors.
The Wingate test, of course, does not mimic sporting events entirely. Sports that require intermittent high-intensity bursts, focus, and psychomotor skills such as football and basketball are quite different. When aspects of these sports were tested there was a significant improvement in both the first and second halves of play with respect to total work and peak power. In competitive swimmers, caffeine improved swim velocity when compared to untrained swimmers with more marked improvement in the second 100 m sprint tested. Affect of caffeine on agility is mixed with the best positive study showing only modest improvements of around 2%. Strength in highly resistance-trained males was improved with caffeine ingestion of 5-7 mg/kg and more weight was lifted and greater peak power obtained.,
Speed Endurance is essentially the performance of high-intensity exercise lasting from 60-180 seconds. The model used to test this parameter is Maximal Accumulated Oxygen Deficit (MAOD), a measure of anaerobic ATP metabolism. MAOD involves high intensity running (125% of VO2max) which brings fatigue on at about the 2-3 minute mark. Tested within this model, caffeine improved run time to exhaustion by 14% (about 30 seconds). NOW GET THIS, When caffeine was tested concomitantly with creatine it was found that acute ingestion of caffeine improved performance by 23.8 seconds compared to creatine use alone. The test was performed after a 7 day loading phase (20 g/day). A synergistic effect of caffeine and creatine was not shown when caffeine was consumed during the loading phase. Caffeine does inhibit elevations in intramuscular phosphocreatine levels. FOLKS…FOLKS….this means that caffeine should not be utilized in the loading phase of Creatine supplementation. AND IT IS LIKELY THAT PREWORKOUT DRINKS WITH CREATINE AND CAFFEINE ARE UTTERLY WORTHLESS. That would mean that almost ALL preworkout drinks are worthless unless it’s just good old black coffee ;). Besides, creatine needs time to get into the muscle cell anyway and would be useless preworkout even without caffeine. Yet caffeine is what you should be using preworkout.
A large body of literature also exists that reports pain perception is attenuated during moderate and intense exercise with 5-10 mg/kg of caffeine. It is very important to realize that this effect on pain perception really is beginning to be seen as one of the primary drivers of caffeine’s effects in both aerobic and anaerobic exercise. You can push farther when the pain is perceived as less.
What else can it help improve?
For vigilance, mood, alertness, and executive control, 200 mg appears to be the best dose. That’s a large cup of coffee. It appears that the preworkout dose of caffeine is still effective as a performance enhancer even if you have a cup of coffee every morning to wake up. That is very good news to me.
Caffeine may help your immune system. The first line of defense against infectious organisms is often NK cells (aptly named Natural Killer cells because they do not need prior sensitization to foreign organisms to kill them). The functional abilities of NK cells decrease after intense exercise explaining, in part, why elite athletes have a high incidence of viral upper respiratory infections after competitive events. Caffeine serves to increase the activation state of these NK cells.
Is coffee just as good?
Most research studies have utilized caffeine in forms other than coffee. Does drinking coffee have the same effect? For many years the study results were mixed on this question, until the article by Hodgson definitively answered this question by showing that coffee consumed 1 hour prior to exercise at 5mg/kg is equally effective as oral caffeine tablets or powders at improving exercise performance. In this study, it should be noted that, while coffee produced the same ergogenic (i.e. performance) effects, the metabolic effects were slightly different. Oral caffeine tabs caused a greater increase in plasma glucose, fatty acids, and glycerol. This is likely due to certain metabolites in coffee, such as chlorogenic acids, producing subtle effects on adenosine receptors.
So what is the bottom line? How do I use this drug to focus my athletic efforts?
Given the existent body of literature, and my own personal experience with stimulant use, it appears that caffeine consumed at a dose of 3-5 mg/kg one hour prior to exercise is the best recommendation. That’s one hour prior to your first working set in the weight room, or the beginning of any high intensity workout. I don’t want to peak during my warm-up or on the way to the gym. Peak when the hard part starts. Caffeine is rapidly absorbed and appears in the blood within 10 minutes, peaking at about one hour post ingestion. Half life is 3-5 hours so you will continue to see effects for up to 8-12 hours post ingestion. If your workouts are in the evening this is probably not going to turn out well for you. Particularly on a leg day when you are squeezing your adrenals to the max. I’ve often laid in bed wide awake all night watching the ceiling fan after an extremely hard day of training the wheels.
Overall, caffeine seems to be most effective in trained subjects with little to no discernable effects in untrained subjects. Thus, it would not be expected to be beneficial until a trainee is at least on the intermediate level of strength or endurance training. Personally, I use the equivalent of a Grande Starbucks coffee (no cream or sugar) one hour prior to the gym. I’m not a fan of black coffee so the taste serves to piss me off at the same time – anger that can be channeled to a good use.
After my workout I will wait at least 30-60 minutes before consuming my postworkout meal that contains a dose of creatine. I don’t normally workout after dinner so I use the remaining arousal and focus from caffeine to focus on reading, writing, or other intellectual activity that I need to get done. This is synergism and is something that you need to take into account when planning more advanced routines if your goal is an existence of excellence: Arete’
Lanny Littlejohn, MD
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|Drink||Type/Size||Caffeine Content (mg)|
|Starbucks Via||Ready Brew||135|
|Dunkin Donuts Coffee||Small||132|
|Dunkin Donuts Coffee||Medium||178|
|Dunkin Donuts Coffee||Large||244|
|Dunkin Donuts Coffee||Extra Large||284|
|5 Hour Energy||Shot||200|
|10 Hour Energy||Shot||422|
|Red Bull||Weak….little wings||80|
|Booty Sweat||Yeah, it exists…||80|
|Rip It||Can(my fav on deployment)||200|
650 drinks cataloged at the above site
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