Considering the huge role that caffeine can play in enhancing (workplace)
productivity, it is worthwhile to study its effects and mechanism with the hope
of maximizing this productivity-enhancing effect. I've done the legwork for
you, so sit back and read. The results might surprise you.
Caffeine has a number of
effects on the body, but the one that is relevant here is that it blocks
adenosine receptors in the brain (by tricking your brain into thinking it is
adenosine.) A decrease in the activity of adenosine (which is a sleep
chemical) increases neuron firing rate and increases focus and concentration.
builds up rather quickly (2-3 weeks) and further, is
near-total. That means that if you drink coffee regularly, pretty soon you
start producing more adenosine in respose; thus you need your caffeine dose
just to get up to your normal level of brain activity, and you're dopey if you
don't take it. Another way to think about it is that the time-average of
adenosine level (and hence, attention level) tends to stay more-or-less
constant, both short term and long term.
Short term strategy.
Let us examine
the way that most people take caffeine -- when they feel sleepy (I will call
changes the attention level from the green line to the blue line (i.e, it
smooths out the fluctuations.) This works great for many people (say,
someone that has a data entry job), because maximum productivity is limited
by external constraints. Other jobs where antagonistic consumption is
essential include assembly line worker and truck driver, where mistakes can
be disastrous but there is little to be gained from peak concentration.
Daily fluctuation in attention level, highly oversimplified. The
green line represents no coffee. The blue line is antagonistic
consumption. The red line is reinforcing consumption.
But other jobs, often characterized by a low level of repetition, have a
markedly different attention-productivity curve. Academic research, for
instance, involves generating ideas that no one has come up with before.
Clearly, an idea that advances the state of the art is unlikely to occur
except when attention level peaks. If you spend your entire day doing
nothing, but all that doing nothing somehow enables you to reach a point
where you understand your research problem well enough that you get insights
that no one ever did before, then that's good research. Writers are another
example: it is common to sit around for days or weeks waiting for
inspiration to hit ("writer's block").
What is common to these tasks is that progress happens in spurts, due to the
fact that they involve frequent
. A cognitive bottleneck can only be overcome when
attention level exceeds a task dependent, typically very high threshold.
Clearly, then, antagonistic caffeine
consumption results in worse-than-normal productivity
, because it
flattens the attention level curve and decreases the fraction of time spent
at peak attention level. Instead,
maximize productivity (the red line). According to this strategy,
the best time to drink coffee is when you are
already very alert
Productivity as a function of attention level for naturally
rate-limited tasks (green line) and tasks with cognitive bottlenecks
(blue line). The former is
concave and the latter is
A job like driving trucks is one end of the spectrum, where productivity is
naturally and insuperably rate-limited. Jobs with frequent cognitive
bottlenecks like at the other end. In each of these cases, the optimal pattern
of caffeine consumption is clear. Most other jobs fall somewhere in between,
and each person must make a reasoned decision about what works best for
The reinforcement strategy has
another element to it. When adenosine peaks, the best response is not to fight it,
but "go with the flow" and (shock, gasp) sleep. Sleep has effects on
memory consolidation and is extremely beneficial in overcoming cognitive
bottlenecks, making the brain maximally alert right after waking up. Thus, a
possibly very effective coffee drinking pattern would be two cups a day, one
early in the morning and one right after an afternoon nap. (Unfortunately,
napping is stigmatized in the Western work culture, despite much scientific
evidence touting the benefits. I hear that such stigmatization is non-existent
in China. Good for them.)
Long term strategy.
Over the long term,
consistent caffeine consumption is as good as nonconsumption, because of (you
guessed it) tolerance. Is there a better strategy? Of course there is.
Periodic abstinence lets adenosine levels return to normal. With complete
abstinence, it takes 5 days to reach adenosine normality; conservatively, and
with imperfect abstinence, a week or 10 days may be required. (Quitting is
hard!) For most people, work involves a natural cyclic pattern of crunches and
lean periods, and moderated coffee consumption to reflect this pattern
will let you enjoy its cognition-enhancing effects more-or-less permanently.
1. Many products contain caffeine, especially sodas. Carelessness about
extraneous caffeine sources will diminish the effect that well-planned
coffee-drinking can have. (Of course, the sugar in sodas is far more harmful
than the caffeine, so that would probably be the least of your worries.)
2. Personally, since I discovered these principles 6-8 months ago, I've had an
absolutely unbelievable time in terms of research productivity. I've also had
3-4 quitting cycles in this time period (which is less than ideal, but I
didn't realize the importance of quitting until later.)
3. There appears to be a generally low awareness of cognition-enhancing
substances in general, such as
I plan to expand on this in a later essay.
4. This essay (and everything else I write on this blog, unless otherwise
stated), is licensed under