Press left arrow to begin.
Arrows to navigate,
“P” for presentation mode,
“N” to reveal content

& stuff    


Face 180
Creative Commons License


Does caffeine really make me …

… more alert?
… more productive?

My Answer

… wait for it …


Let's get science-y!

Let's measure our productivity

While using caffeine

While not using caffeine

Now, anecdotes aren't data

(but they're better than nothing)


Concentration vs coffee chart

What does caffeine do?



Short digression



What does Adeonsine do?

Adenosine is an inhibitory neurotransmitter.

It inhibits the release of excitatory neurotransmitters like dopamine, acetylcholine or noradrenalin. (Wikipedia: Adenosine)

Regulates sleep/wake cycle.

And caffeine?

Caffeine is an adenosine antagonist.

It binds to the same receptors as adenosine would, but does not activate them.

500x the oatmeal adenosine Source: The Oatmeal

What that means

Caffeine does not make you more awake

But suppresses the feeling of tiredness
(In your brain, but also in your muscles.)
... while adenosine levels keep increasing

The consequences

Caffeine has a half-life of ~4-8h
(less in smokers; more during menstruation; ...)

Adenosine keeps accumulating
Sooner or later, you will crash

Tiredness is only suppressed
And then masked with even more caffeine

The body reacts

More receptors for adenosine
building a tolerance → need to increase dosage

tolerance within one week

... almost independent of dosage


When regular caffeine users were given caffeine this simply returned them to their baseline, and did not enhance their alertness. Non caffeine users saw no benefit from taking caffeine.

Consequently (…)

The take home is that regular use of caffeine produces no benefit to alertness, energy, or function. Regular caffeine users are simply staving off caffeine withdrawal with every dose – using caffeine just to return them to their baseline.


Detoxification takes 2–6 days

Withdrawal symptoms are stronger the higher your usual dose is
Headache, irritability, insomnia

Then, re-normalize your circadian rhythm
(up to four weeks)

Light and shadow

We keep staring at bright screens

We are surrounded by bright LEDs
(many of them blue or white)

Light signals our brain

Oh frabjous day! Callooh! Callay!

Let there be darkness!

In reality, it's not always daytime.

f.lux to the rescue!


Let there be darkness! (…)

F.lux makes the color of your computer's display adapt to the time of day, warm at night and like sunlight during the day.

Flux settings


Enjoy your
psychoactive drugs!

Sleep well
be productive!

Coffee break!

Thank you!

Face 180
(follow me on Twitter!)