I never check for updates from the journal of Neuropsychopharmacology, so you (well, I) can thank a recent BBC article for letting me know about this study. It is somewhat relevant not only because it’s officially Coffee Week here at ST, but because it references caffeine tolerance which is apt for the previous two articles showing caffeine’s ergogenic potential.
The study itself was a collaboration between British and German researchers investigating the effect caffeine can have on different people. Specifically, they wanted to look at people with a variation of the ADORA2A gene (the gene coding for the adenosine A2A receptor) who suffer anxiety from caffeine use, and to determine whether the anxiety can be lessened with frequent use. The result of this is not the interesting part of this study however, as I will detail below. In the past two articles I avoided going into any detail about caffeine pharmacology, but I guess for this one it is required as I don’t want anyone getting lost as they read this.
Caffeine is an antagonist of the A1 and A2A adenosine receptors, thereby inhibiting the breakdown of Cyclic Adenosine Monophosphate (cAMP). Adenosine is an inhibitory neurotransmitter that slows nerve cell activity. It is also important for energy transfer as up to three phosphates can be attached to it to form adenosine triphosphate (ATP), something I discussed in more detail in the article Phosphorous an appetite regulation. By inhibiting the adenosine receptors, nerve cell activity is increased, leading to mental stimulation. This is how a cup of Joe in the morning perks you up.
The near-four hundred participants were directed to have a sixteen-hour caffeine wash-out period. Two hundred and seventeen of these participants were medium/high coffee drinkers, sinking one to six cups a day, so this must have been a pretty rough time for them! The other hundred and sixty-two participants either never or rarely drank coffee. During the experiment, the participants were randomly given a 100mg caffeine espresso shot, or a placebo. After ninety minutes, they got another 150mg shot or placebo. Here’s where it gets interesting because this is the only part of the study that may be relevant for the average bodybuilder or athlete – the medium/high coffee drinkers receiving caffeine reported alertness levels no higher than that of those who rarely drink coffee that were given the placebo! In other words, regular coffee drinkers drink coffee to make themselves “normal”!
As a regular coffee drinker I can kind of see the reality in this. And I can definitely relate to the fact that the medium/high coffee drinkers given placebo tended to get a headache. I’m sure some of you reading can relate to this also. So the take-home message for this update is that for best impact cycle your stimulant usage and take time off coffee drinking every now and then.
Source: Rogers PJ, Hohoff C, Heatherley SV, Mullings EL, Maxfield PJ, Evershed RP, Deckert J, Nutt DJ. Association of the Anxiogenic and Alerting Effects of Caffeine with ADORA2A and ADORA1 Polymorphisms and Habitual Level of Caffeine Consumption. Neuropsychopharmacology. 2010 Jun 2.