A few years ago I was preparing to race an Ironman 70.3 in Syracuse, New York. My training was going really well, and my confidence was high. So high that I got it into my head that I may be able to qualify for the world championships.
For someone like me, qualifying meant I would have to go the extra mile—the metaphorical mile, that is. So I started looking into some of the more fringe and less significant advantages I could incorporate. Things like drinking beet juice, taking ice baths, and for the two weeks before the race, abstaining from my most beloved of beverage based drugs—caffeine!
I know, right?
The point of this coffee abstinence was to allow my body to regain its sensitivity to caffeine. Then, in theory, when I had that big cup of glorious coffee on race morning, I would feel it.
In the end, I am not sure I felt much more of a caffeine rush than I usually do. But what I did feel was the lack of caffeine in my system for those two weeks leading up to the event. Let's just say I was not my usual chipper and positive self.
Caffeine is well known to enhance and prolong exercise performance. Most specifically, doses of 3 to 13 mg of caffeine per kilogram of body weight (mg/kg) have been shown to improve exercise performance.
How does it do that? Well, caffeine's stimulating effect on the central nervous system has been shown to reduce feelings of fatigue, lower perceived exertion, and even lower levels of perceived pain. Caffeine also improves mental acuity and sharpness, it helps maintain laser-like focus, and it even improves some technical skills both during and after strenuous activity. And, if that isn't enough, it's also believed to enhance the body's ability to use its own fat as fuel, which can effectively increase the time to exhaustion in endurance events.
To get a little nerdy and "sciencey" for a second, the theory is that caffeine blocks something called adenosine receptors in the brain. That leads to higher levels of dopamine and noradrenaline, which both can lead to all the aforementioned magical performance-boosting benefits.
Abstaining from caffeine
It's believed that the easiest and most effective way to get a performance boost is by first allowing your body to regain its natural state of sensitivity to caffeine. (That was the theory back in my racing days, and it holds true in most circles today.) That means going cold-turkey for ten days to two weeks.
But in 2017, a study in the Journal of Applied Physiology from the University of São Paulo, tested that assumption. Researchers put 40 well-trained cyclists through a series of time trial events. Each event lasted 30 minutes and was performed by cyclists who were either having nothing but water, taking a caffeine placebo, or taking an actual 6 mg/kg dose of caffeine one hour before the trial. And these lucky folks only had to abstain from caffeine for 24 hours before each event!
At the beginning of the study, each of the cyclists was asked about their caffeine-drinking habits. Then, based on their answers, they were divided into one of three caffeinated groups: low (two to 101 mg/day), moderate (104 to 183 mg/day), and high (190 to 583 mg/day). The initial assumption for the study was that the lesser-caffeinated cyclists would experience the biggest boost in performance. And the higher-caffeinated group would see the lowest boost—especially since the abstinence period was so short (24 hours.) Contrast that with the two weeks of caffeine deprivation I inflicted upon myself!
Not surprisingly, the caffeine did boost everyone's performance and speed by 2.5% on average compared to the placebo group. It also boosted everyone's performance 3.3% more than the plain water group. That's interesting in and of itself—there was a 1.2% placebo advantage! But placebo effects aren't what we are talking about today. For that you can check out my article called Can the Placebo Effect Enhance Athletic Performance?