Written by: Andrew Pardue
What you’re looking at: ~ 1900 words / 9 minute read time
Popeye has his spinach; Green Lantern has his ring, Superman the sun… our super power energy source? Good ole’ caffeine. Knock back some pre-workout or coffee and we’re off leaping tall buildings and feeling stronger than ten men, or at least able to interact with other people. Below is a full breakdown of the physiology, performance benefits, and practical applications for maximizing the effects of caffeine while periodically limiting intake to keep yourself as healthy and productive as possible.
Although there have been multiple theories on the exact mechanism of caffeine on reducing fatigue, the most well-supported theory tends to be that of caffeine acting as a competitive inhibitor to adenosine receptors. By actin as a competitive inhibitor, caffeine stimulates the central nervous system (CNS) through binding to adenosine receptors before adenosine can, which results in reduced fatigue.1
Adenosine accumulates throughout daily activities and exercise through the metabolism of ATP. Once produced, it contributes to feelings of sleepiness and fatigue as the day progresses, leading to eventual, nightly sleep.2 Part of the reduction in fatigue is due to the subsequent reduction of fatigue-related neurotransmitters such as dopamine, serotonin, GABA and others within the body upon adenosine inhibition.3
Let’s Talk Tolerance
Although caffeine is very effective as a competitive inhibitor to adenosine receptors, we’ve all experienced the decreased effect of caffeine after continued use. The increasing tolerance to caffeine is thought to occur after the body creates more adenosine receptors in an effort to maintain proper adenosine balance; thus creating an increased requirement for caffeine consumption to achieve the same effect.
Although the period of time before tolerance increases can differ between individuals, some research has helped shed light onto some general guidelines for how long a particular, daily caffeine serving can be consumed before receptor up regulation. It seems that a daily dose of 400mg/day didn’t result in a notable tolerance in the first week of consumption, while 2 weeks of 400mg/day or greater lead to significant increases in tolerance during a study among 45 healthy individuals. This is why that single cup of coffee or scoop of pre-workout, rather quickly develops into 2, 3 or more servings for most individuals. 4,5
If an individual decides to take a break from caffeine, the sudden availability of adenosine receptors, along with the increased quantity of receptors, is thought to create a sudden rush and binding of adenosine to receptors. This adenosine ambush leads to the all too common caffeine headache. Pounding headaches and overwhelming fatigue from stopping cold turkey is a huge reason why performing a taper, rather than an all-out break, is a smart idea. Luckily, the following section is written to help you successfully do just that.
Performance Benefits of Caffeine & Suggested Relative Dose
Acute caffeine consumption has been shown to support greater time to fatigue, strength output, and mental acuity. For those focused on increasing strength, a study in 2010 showed improvements in bench press 1RM among females 1 hour after consuming 6mg/kg (i.e. 360mg for a 132lbs female).6 Others have shown a 5mg/kg dose to improve strength and power output during exercise in male athletes.7
For runners or cross trainers out there, another study showed that consuming 100mg caffeine in addition to 45 grams carbohydrates lead to significantly improved time to exhaustion and mental performance in endurance training athletes compared to those consuming only carbohydrate or a zero calorie, zero caffeine placebo.8 Even our sport-specific athletes can benefit from caffeine consumption through its improvements in reaction time, such as reacting to a volleyball spike, or a wide receiver’s cut during a route.9
When covering the benefits of caffeine consumption, the question of hydration typically arises given the common acceptance that caffeine causes dehydration. Although this notion has been largely accepted as fact by the fitness community, very little research supports this. On the contrary, a very large majority of research on hydration alterations of caffeine show little to no effect on diuresis.10,11
Based on the available research, it seems that anywhere from 3 to 6mg/kg caffeine consumption can have safe, ergogenic effects for athletes (i.e. 270-545mg for a 200lbs male or 175-355mg for a 130lbs female athlete) while lower servings can still improve cognitive performance for non-habitual consumers. Although an athlete could consume above this range, it’s unlikely to produce greater performance benefits, but very likely to cause nausea, jitters, and disrupted sleep.
For those interested in maximizing effect, it would seem prudent to start at the lower end of the suggested range, limit intake to around the most challenging of weekly training sessions, and increase serving size only as needed toward the upper range.
Capitalizing on your Caffeine
Considering that more isn’t always better when it comes to caffeine consumption, it can be relieving to know that other factors can contribute to the effectiveness of a caffeine dose, and help athletes get more out of their caffeine consumption without constantly upping the serving size.
As a little background into caffeine itself, the substance is water soluble, and absorbed through the stomach lining into the blood stream, then finally transported across the blood-brain barrier. Since caffeine is absorbed through the GI tract, the timing of caffeine consumption relative to recent meals will affect the degree in which caffeine is felt in terms of mental and physical benefits. Its solubility in water also stands to reason as another benefit of maintaining proper hydration as caffeine metabolism can likely be improved simply by consuming enough water throughout the day. For those looking to maximize the effects of their caffeine regiment, keeping daily water intake in check, and consuming caffeine containing beverages or supplements before, or at least 1 hour after consuming a meal can help with metabolism and absorption.
As a side note, as with many ingredients used with the fitness industry, there seems to be some inter-individual variability with caffeine consumption. Along with bodyweight, consumption frequency, and even possibly gender difference- all things being equal, some people may simply notice more or less effects given the same serving size and caffeine source. This makes starting at low intakes and experimenting with different servings important for each athlete to find the minimum effective dose for their personal needs.
In terms of intake timing throughout the day, it should be noted that caffeine is known to have a half-life of roughly 3-6, meaning it takes somewhere between 3-6 hours for half of the caffeine consumed to be metabolized and eliminated. This half-life can be dependent on a multitude of factors such as the type of caffeine consumed, which we will briefly cover next. However, generally it is a good rule of thumb to abstain form caffeine consumption at least 6-8 hours before planned bedtime to reduce risk of sleeplessness.
Common Forms of Caffeine
Caffeine is a general term, however with the evolution of the fitness industry, it is now available in many different synthetic and naturally derived forms, especially in sports nutrition supplements. Each version tends to have slightly different benefits, but the physiology of caffeine remains largely the same.
Many products will include extracts of natural caffeine sources rather than synthetically created versions. Coffee bean, green tea and cocoa bean extracts are common versions. These should provide a more concentrated source of naturally found caffeine, as well as trace sources of antioxidants and other substances found through these extracts.
Caffeine anhydrous is probably the most common form of caffeine seen in dietary supplements, and is essentially a dehydrated version of natural caffeine- making it easy to include in various powder & pill products. Other names for this version are often seen on labels as 1,3,7-trimethylxanthine or methyltheobromine. Caffeine anhydrous is most closely related to the natural version of caffeine, such as that found in coffee, tea etc.
Di-Caffeine Malate (Infinergy™) (60-65% Caffeine)
Caffeine and malic acid are bonded together in this version to allow for a purported, more sustained, smoother energy source. It’s also thought to reduce digestive issues that some may experience with the anhydrous form. Caffeine sources that provide a prolonged, more sustained energy source such as Di-Caffeine Malate and PURENERGY should be consumed further out from planned bedtimes than natural caffeine sources given the extended half-life, but may allow for extended training output for athletes.
PURENERGY® (40-45% Caffeine)
PURENERGY® is a patented version of caffeine combining pterostilbene (pTeroPure®) and caffeine to provide what is designed to be a longer half life, greater bioavailability (better absorption and use), and other benefits to improve user experiences in cognitive and physical performance. This version is becoming more readily available through sports nutrition supplements and thought to reduce jitters or “crashes” for athletes.12
Caffeine Content in Common Beverages (8oz serving)
|Diet Mt. Dew:||36mg|
|Monster Zero Ultra:||70mg|
After chronic use of caffeine, we don’t necessarily want to continually increase our caffeine consumption and risk rises in cortisol, increased vasoconstrictions or chronic sleeplessness. For anyone that’s been using given caffeine source, or sources, rather consistently for several weeks, it can be a good idea to perform a caffeine break.
By gradually tapering, then taking a complete break from caffeine intake, we can essentially “reset” our bodies by allowing time for adenosine receptor down-regulation, returned blood vessel dilation, and re-gain normal, quality sleeping patterns. For athletes constantly working to remain healthy, and maximize muscle size and strength, these tapers can be especially beneficial given chronic caffeine consumption can significantly elevate cortisol levels, which in turn can disrupt muscle growth and immune function.13 Whether we’re in a fat loss phase or growth season, keeping cortisol levels within a healthy range can be important for maximizing improvements.
A good rule of thumb that has worked well for my clients, as well as myself, is to perform a weeklong taper, followed by a weeklong caffeine break. This gives plenty of time to gradually work away from caffeine dependence, reap the benefits of the caffeine break, but to also reduce the withdrawal symptoms often seen when first coming off regular caffeine used. Of course some people prefer to cut the process short and just stop cold turkey for a week, but the success rate of a complete caffeine break seems to be far lower for those that stop cold and deal with sometimes overwhelming caffeine withdrawals after excessive, chronic consumption.
Example of a Proper Caffeine Break
This example is using someone that has worked up to an average of 500mg/day caffeine intake and is looking to perform a full caffeine break as described above. Generally, tapering intake by ½ with each reduction throughout the week can be a good rule of thumb. Performing caffeine tapers just before, and the full caffeine break during de-load phases of training can help athletes mitigate reductions in training performance.
Week 1 (Taper Week)
Example 1: (2) cups of coffee
Example 2: (1) 16oz Rockstar Zero energy drink)
Example 1: (1) cup of coffee
Example 2: (2) diet colas and (1) cup of green tea)
Example 1: (1-2) diet colas
Week 2 (Break Week)
The next 7 days are taken completely off of any form of caffeine. Decaf coffee, caffeine-free diet drinks, and non-stimulant pre-workout products are great to have on hand so you can enjoy the beverages and pre-workout rituals you are used to, while still allowing yourself the benefit of a complete caffeine break.
Cracking the Caffeine Code
It’s not exactly fair that Popeye can get psyched up simply from eating spinach any time he wants, and we have to be so strategic with our caffeine intake. However the good news is, with a little planning, we can greatly limit the negative effects we experience with caffeine use, while getting the most out of each training session. You may not be leaping over buildings any time soon, but those extra sets of bench press just got easier.
- Davis, J. M., Zhao, Z., Stock, H. S., Mehl, K. A., Buggy, J., & Hand, G. A. (2002). Central nervous system effects of caffeine and adenosine on fatigue. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology,284(2). doi:10.1152/ajpregu.00386.2002
- Porkka-Heiskanen, T., & Kalinchuk, A. V. (2011). Adenosine, energy metabolism and sleep homeostasis. Sleep Medicine Reviews,15(2), 123-135. doi:10.1016/j.smrv.2010.06.005
- Caffeine for the sustainment of mental task performance: formulations for military operations. (2001). Washington, D.C.: National Academy Press. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK223808/.
- Boulenger, J., Patel, J., Post, R. M., Parma, A. M., & Marangos, P. J. (1983). Chronic caffeine consumption increases the number of brain adenosine receptors. Life Sciences,32(10), 1135-1142. doi:10.1016/0024-3205(83)90119-4
- Varani, K., Portaluppi, F., Gessi, S., Merighi, S., Ongini, E., Belardinelli, L., & Borea, P. A. (2000). Dose and Time Effects of Caffeine Intake on Human Platelet Adenosine A2A Receptors : Functional and Biochemical Aspects. Circulation,102(3), 285-289. doi:10.1161/01.cir.102.3.285
- Goldstein, E. R., Jacobs, P. L., Whitehurst, M., Penhollow, T., & Antonio, J. (2010). Caffeine enhances upper body strength in resistance-trained women. Journal of the International Society of Sports Nutrition,7(1), 18. doi:10.1186/1550-2783-7-18
- Woolf, K., Bidwell, W., & Carlson, A. (2008). The effect of caffeine as an ergogenic aid in anaerobic exercise. International Journal of Sports Nutrition and Exercise Metabolism,412-429. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/18708685.
- Hogervorst, E., Bandelow, S., Schmitt, J., Jentjens, R., Oliveira, M., Allgrove, J., . . . Gleeson, M. (2008). Caffeine Improves Physical and Cognitive Performance during Exhaustive Exercise. Medicine & Science in Sports & Exercise,40(10), 1841-1851. doi:10.1249/mss.0b013e31817bb8b7
- Durlach, P. J. (1998). The effects of a low dose of caffeine on cognitive performance. Psychopharmacology,140(1), 116-119. doi:10.1007/s002130050746
- Millard-Stafford, M. L., Cureton, K. J., Wingo, J. E., Trilk, J., Warren, G. L., & Buyckx, M. (2007). Hydration during Exercise in Warm, Humid Conditions: Effect of a Caffeinated Sports Drink. International Journal of Sport Nutrition and Exercise Metabolism,17(2), 163-177. doi:10.1123/ijsnem.17.2.163
- Coso, J. D., Estevez, E., & Mora-Rodriguez, R. (2009). Caffeine during Exercise in the Heat. Medicine & Science in Sports & Exercise,41(1), 164-173. doi:10.1249/mss.0b013e318184f45e
- (n.d.). Retrieved May 11, 2017, from https://chromadex.com/purenergy/
- Lovallo, W. R., Farag, N. H., Vincent, A. S., Thomas, T. L., & Wilson, M. F. (2006). Cortisol responses to mental stress, exercise, and meals following caffeine intake in men and women. Pharmacology Biochemistry and Behavior,83(3), 441-447. doi:10.1016/j.pbb.2006.03.005