The History and Efficacy of Caffeine on Physical Performance

Kyle Hunt
12 min readMay 20, 2020


People are always searching for new and exciting ways to boost performance. It started with the early Olympic athletes who used food such as deer liver & lion heart hoping that by eating these items it may affect their strength, speed, and even bravery. This drive for new ergogenic aids is evident in the supplement industry today. New products are promoted every year despite limited and unsubstantiated data. Most of these products come and go without leaving much of a mark. However, a few supplements have stood the test of time and demonstrated strong evidence, one of those is caffeine.

Caffeine is a widely recognized psychostimulant compound with a long history of consumption by humans. The history may go back as far as 2737 BCE [1].

What is Caffeine and What Does it do?

Caffeine is one of the most widely consumed compounds in the world, not just by fitness enthusiasts, but by nearly everyone. In addition to increasing arousal, caffeine can reduce pain and perceived exertion during exercise, improve aerobic endurance, muscular endurance, and muscular power and strength.

If you ask someone what does caffeine does, they will likely say something along the lines of, “it gives me energy”. But, that is not entirely true. When it comes to energy, the macronutrients — carbohydrates, fat, and protein, and therefore, calories are what’s used in the body for our daily energy requirements. This is the concept of energy balance and the Laws of Thermodynamics.

Caffeine’s main mechanism of performance-enhancing effects has to do with influencing the CNS, more specifically antagonizing adenosine receptors [2]. Adenosine causes sedation and relaxation when it acts upon its receptors, located in the brain. Caffeine prevents this action and causes alertness and wakefulness. This inhibition of adenosine can influence the dopamine, serotonin, acetylcholine, and adrenaline systems.

Does it Improve Performance?

At the end of the day, what we want to know is — does it work? Unlike a lot of supplements, caffeine provides immediate feedback on effectiveness. When you take it, you can feel the effects very soon. It’s a supplement that I feel doesn’t need much selling. On the flip side, a supplement like creatine, which also has a ton of scientific support, does need a sales pitch because you won’t notice any immediate effects, in fact, it often takes an extended period of time to notice any changes.

When it comes to caffeine and performance, we want to look at a few things.

Endurance: The greatest benefit seems to be for aerobic endurance. There is the widest amount of research backing the ergogenic effects of endurance performance, and it has been researched the longest.

Strength/Power: In recent years, the research has started to focus less on endurance and shift toward anaerobic performance specifically looking at caffeine’s effects on muscular endurance, muscle strength, and muscle power. The consensus seems to be there is a small but statistically significant benefit to strength and power. Again, this is huge because there are very few legal substances that actually consistently show a benefit for strength.

However, with that being said, I think there is another reason why caffeine is so popular in the strength community and that has to do with the cognitive and mood-enhancing effects. The cognitive and mood effects of caffeine are well documented. It’s not something I need to cite research for you to believe. Just go step in line at your local Starbucks and ask around, you will get the picture. I think just the feeling of alertness and euphoria when we walk into the gym helps get our minds in a good place for a productive workout. Caffeine absolutely has benefits beyond the placebo effect. That has been well documented in the literature. With that being said, I think there may be a slight placebo effect to taking a pre-workout dose of caffeine before hitting the gym.

Pre Workout Supplements Timeline:

From what I have gathered, the first pre-workout supplement was created in 1982 by Dan Duchaine. Before this lifters probably just drank coffee before training. As a side note, Dan was a pioneer in the fitness space back in the 80s and early 90s. This was obviously before my time but I have read a lot of his stuff. He was big in the drug scene, considered a steroid guru so to speak, but he also had unique ideas on training and nutrition as well. The book Steroid Nation by Shaun Assael talks about him quite a bit. That’s actually a great book that I highly recommend on the rise of steroids in sports.

In 1982, the product Ultimate Orange was created. Its main ingredient was Ephedra. It took advantage of the Ephedra and Caffeine stack which has been shown to work synergistically with each other. In the 90s ephedra was banned so they had to change the formula. I think they replaced the ephedra with synephrine which is structurally similar. When I first started training in the early to mid-2000s, Ultimate Orange was still a popular product.

However, the most popular pre-workout product of that time was by far BSN’s N.O Xplode. From what I remember, it came in fruit punch or orange flavor, it fizzed up when you mixed it, and outside of caffeine, nothing else in it did much. It was essentially just expensive caffeine. I never liked it because it tore my stomach apart. There were a few other pre-workouts at the time, I remember Gaspari had Superpump 250, but the most popular product was NO Xplode. I think a lot of the popularity had to do with BSN having Ronnie Coleman promote it. That was huge. Ronnie was BSN. Their marketing was fantastic. Actually, a lot of supplement companies had fantastic marketing back in the day. I know they certainly influenced me to spend hundreds of dollars on supplements each month during my teenage years.

In my opinion, the pre-workout supplement game changed when Jacked 3D was released. This was the first pre-workout that I really enjoyed. It was a concentrated formula so it had a small scoop, but it packed a big punch. The key ingredient USP Labs used was DMAA which was created by Patrick Arnold who was the chemist that worked with Balco designing steroids for people like Barry Bonds, Marion Jones, Jason Giambi, etc. A great book to dig into more information on Balco is Game of Shadows.

Jacked 3D was so popular…that is until people started having adverse side effects from DMAA and it ultimately got banned.

Bringing Things Back To Caffeine — Dosages and Timing

One of the things people may be most surprised about in terms of caffeine is the actual dosages supported in the literature are pretty high. Most research uses 3–6mg/kg with most of the actual performance benefits in the 4–6mg/kg range.

To put that into perspective what 4–6mg/kg looks like:

150lbs = 270–405mg

175lbs = 320–480mg

200lbs = 360–540mg

250lbs = 450–675mg

I always recommend starting out on the low end and trying to milk that for as long as you can. Caffeine is one of the few substances where you can see some benefit at a wide range of dosages. It’s not an on/off or black and white situation.

In a “perfect” world, you would assess your tolerance and take the studied dose in the pre-workout window. Based on how long it takes caffeine to reach peak levels in the bloodstream, you want to take your pre-workout caffeine dose 30–60 minutes before training.

However, the problem is, most people can’t handle huge boluses of caffeine all at once. In fact, I would bet most people will feel some negative effects at the higher end dosages — headaches, rapid heart rate, jitters, anxiousness, and just overall uncomfortable. That doesn’t lend itself to optimal performance. So, if you have built up to the point where you can handle a high intake, or want to try and get the most out of your caffeine, I have a workaround.

There is a way to use the half-life of caffeine in our favor. A half-life refers to the time it takes for the concentration of a substance to be reduced by 50%. So, after the half-life time period, the starting dose will be cut in half. We will talk more about half-life when it comes to sleep.

Through trial and error, I have found if I consume caffeine in the morning, and again in the afternoon, the effects of the afternoon dose are more pronounced. Although this is not necessarily supported by research, it is something I have played around with myself over the years.

For example, I may have a cup or two of coffee in the morning. Let’s say, it’s 200mg at 8 am. Based on the half-life of caffeine, which is between 4–6 hours, at 2 pm I still have roughly 100mg of caffeine in my system. At this point, I take 2 scoops of PR Breaker Materia which is 300mg, and train 30 minutes later. I admit, there may be other factors at play, but I have found the afternoon dose is more effective after having caffeine in the morning.

For me, this is the best of both worlds. As I said, I don’t know of any research on the validity of this, but it might be something that gets looked into down the road.


One of the issues brought up a lot about caffeine is that it loses its effectiveness over time. While it’s true that you develop a tolerance to repeated use the benefits do not completely diminish. If this is something you are worried about, you do have a couple of options.

One option is to just use caffeine on days when you have the hardest workouts. If you only use it a couple of times per week, it will likely take longer to lose its effectiveness. Personally, I don’t do this. I have accepted the fact that I am a habitual caffeine user and although the effects may be diminished, they are still prominent enough where it doesn’t bother me and make me feel like I’m losing much. You also don’t have to take the full dose every day.

The other option is to take time off from caffeine before you want to really take advantage of the benefits. This comes up a lot for powerlifting meets. It’s not uncommon for people to take a break from caffeine the last week or so before a meet to act as a reset. If you decide to do this, it typically takes longer than a week to really make much of a difference. You probably want to take caffeine out 2–4 weeks before the meet. Be prepared for mild symptoms of withdrawal starting 24–48 hours after your last caffeine dose.

Health and concerns?

In my opinion, most of the health concerns around caffeine are exaggerated and misguided. One of the reasons why I wanted to start out talking about the history of caffeine intake is because caffeine is one of the unique substances that we actually have hundreds of years of use to use as data. That can’t be said for nearly any other performance supplement or drug. If it was dangerous, caffeine has been so widely used, we would know about it.

There has been pushback against energy drink consumption in recent years. Again, most of this is misleading. Almost all of the research on the “dangers” of energy drink usage has to do with mixing it with alcohol, large amounts of sugar, and the potential to lead toward toxicity. So, essentially, they are saying if you mix energy drinks with alcohol, and consume in large quantities, they may be an issue. Ok, good to know.

Keep in mind, the lethal dose of caffeine is estimated to be 10,000mg. So, you would have to drink about 50 energy drinks to equal 10,000mg of caffeine. That is not to say there won’t be dangers of caffeine below that intake amount.


Dehydration is another misconception that you see thrown around a lot. Caffeine is a mild diuretic however, the degree in which is so small, when you consume caffeine as a liquid as in coffee, pre-workout, etc. the liquid in the drink outpaces the diuretic effect. To put it another way, when you drink a cup of coffee or pre-workout, you are more hydrated after you drink it than you were beforehand.


The urge to go to the bathroom is more closely related to coffee than caffeine. There is research that shows even decaffeinated coffee can cause people to use the bathroom.

If you used to take those old school pre-workouts back in the NO Xplode days, those used to make you hit the bathroom pretty fast as well. I don’t know if it was magnesium or sugar alcohol or what but they had the same effect.

It doesn’t seem to be strongly correlated to caffeine though.


When it comes to health concerns and caffeine, the big one is sleep. Quality sleep is so critical for optimal performance both cognitively and physically. I feel like as a society we have so many things pulling at us, sleep is the one area that is often neglected. When my clients have sleep issues, the first thing we do is look at caffeine, both total intake and dosage timing. Make sure you are sleeping 7–9 hours per night before you worry about optimizing your caffeine intake.

Remember when we talked about the half-life? Well, that is a big concern. Caffeine stays in your system on average for 4–6 hours. However, how people metabolize caffeine is highly individual. What that means is, some people metabolize it faster than others. Your half-life may be less than or more than the 4–6 hour range.

If you run the numbers, training at night is going to be an issue. If you work a 9 to 5 job, go home change, and get to the gym around 6 pm, that pre-workout caffeine does is likely still going to be significant enough to affect sleep quantity or quality.

If you must train at night, you have to look at the trade-off. How much caffeine can you get away with and still fall asleep on time? This might be a case where you want to stagger your intake of caffeine throughout the day and only consume a small dose pre-training to “top it off”. This method probably won’t be “optimal” but neither is not sleeping well.

The other option is to forgo caffeine pre-workout altogether. In this case, I recommend finding a good caffeine-free pre-workout, like Orange Creamsicle Materia which still has citrulline malate, beta-alanine, etc.

Don’t try to burn the candle at both ends. Caffeine is not a good crutch to make up for lack of sleep. You may be able to get away with it for a while, but eventually, it will catch up to you.

What are the best sources — coffee, pill, or pre-workout drink?

The best source of caffeine is the one you enjoy. There was actually a time when it was thought caffeine as a supplement was more effective than from coffee. This was widely accepted. It was part of ISSN’s Position Stand on Caffeine and it was even included in the third edition of the NSCA Essentials of Strength Training and Conditioning which is the CSCS textbook. However, this was all based on one study. In recent years it has been found that it really doesn’t matter how you consume caffeine, caffeine is largely caffeine.

The biggest issue with coffee is it’s hard to know how much caffeine you are actually taking in. I usually say 1 cup of coffee is equivalent to 100mg of caffeine but it really depends on the variety of the coffee bean, roasting method, grind, how much water used, and the brewing time. There was actually a research study done where they ordered a 16oz coffee from Starbucks 6 days in a row, tested the caffeine intake, and found it ranged from 259mg all the way to 564mg! So there was over a 300mg difference from the same size and blend of coffee ordered from the same Starbucks [3].

This is the only thing that can make coffee a little challenging. However, it probably won’t make a huge difference. If you are brewing your coffee at home you likely won’t see huge variations in caffeine content. At the end of the day, I recommend just consuming your caffeine by whichever method you enjoy.

I have always liked drinking my caffeine, that’s why I tend to be a coffee and pre-workout guy, but you can just as easily take a caffeine pill.

My recommendations

Overall, I am in favor of caffeine supplementation. As a natural athlete, there just aren’t that many ergogenic aids that actually increase performance. As long as you keep dosages within reason and are able to sleep well at night, caffeine seems to be reasonably safe.

To take advantage of the performance benefits, aim to consume between 3–6mg/kg of body weight per day. If you need to, split it up between 2 doses, with the larger dose being pre-workout.

If you start having sleep issues, lower your intake, and/or consume it earlier in the day!

*Note: This is a loose transcript from episode 268 of The Absolute Strength Podcast. Listen to the podcast here.

Papers mentioned on the show:

  1. Willson C. (2018). The clinical toxicology of caffeine: A review and case study. Toxicology reports, 5, 1140–1152.
  2. Davis JK, Green JM. Caffeine and anaerobic performance: ergogenic value and mechanisms of action. Sports Med. 2009;39(10):813‐832. doi:10.2165/11317770–000000000–00000
  3. McCusker, Rachel & Goldberger, Bruce & Cone, Edward. (2003). Caffeine Content of Specialty Coffees. Journal of analytical toxicology. 27. 520–2. 10.1093/jat/27.7.520.
  4. Other article referenced in the podcast:

To learn more about caffeine, check out’s piece on caffeine, and Eric Trexler’s article on Stronger By Science.

Books mentioned on the show:

Steroid Nation and Game of Shadows

Connect with Kyle Hunt:

Instagram: @huntfitness

YouTube: @HuntFitnessTV

Hire me as your coach:

Originally published at on May 20, 2020.