How much coffee should you drink to be “productive”?

Warning: the following post includes a discussion on the results of self-experimentation using chemicals to improve my ability to concentrate. As I mention here, you should only mess with your body/mind if you are satisfied that you are doing so in a safe manner and that you are aware of all the risks. Even then, proceed with caution.

The experiment:

When I was in the final, desperate, stages of my PhD, I began to experiment with my psychopharmacology. I wanted to know exactly how much coffee I should be drinking to optimise my ability to put in the long hours required, but at the same time not lose focus. That one simple question led me on a fascinating journey into the world of caffeine and performance. Over the course of a month I experimented with coffee, carbonated caffeine based beverages, caffeine supplements (think: ‘pills’), tea and anything else I could think of that had caffeine in it. As you might well imagine, that particular journey had plenty of highs and lows.

One of the highs was when I stumbled upon this piece of research that looked at the effects of caffeine in Navy SEALS who were subjected to sleep deprivation during the infamous Hell Week training period. Navy SEALS were administered dosages of caffeine that ranged from 100mg to 300mg and they were tested for various effects on their cognitive abilities. Now I’m not suggesting that the final stages of a PhD is as demanding as Hell Week (although it felt like it at the time), but the nights are long and it requires a significant amount of focus on detailed work. One has to be sharp.

It turns out that 200mg of caffeine is the optimum dosage that will sustain alertness and will that still have a positive effect after 8 hours. Now the tricky bit lies in knowing how much caffeine is in any one particular drink (or supplement). It seems that the range can be large indeed depending on a variety of factors (method of extraction, size of beverage etc), so I relied on the USDA stats for coffee that was brewed from grounds with tap water (the most common method I used for making my coffee during this period), which suggests that the dosage is about 95mg per cup. Let’s call it 100mg.

This means that for the best results, I* should slam down two cups of brewed coffee to enjoy sustained, positive cognitive results.

Wilfully ignoring the science:

Of course that all sounds fine in theory, but there are many factors that means that each individual’s response to 200mg of caffeine will be different – not the least of which is whether or not someone believes they have a ‘tolerance’ to caffeine or not. Now, I would suggest that I drink more than the average amount of coffee in a day. I seem to average about four cups per day with most of the doses coming in the early part of the day. Since I drink so much of it, I expected that my tolerance is higher. So I began to dose higher (<– not so smart). Furthermore I began to mix with various forms of caffeine – a mixture of caffeine pills, ‘energy drinks’, flavoured milks, soft drinks… you name it.

While there is research to suggest that there is no material impact in such things as coordination (steadiness of hand) on doses of 200mg whether the participants drink coffee regularly or not, the fact was that I thought I was more immune to the effects due to my ‘higher than average’ consumption levels. So I drank more. And that, dear friends, is where the trouble began.

I can reliably inform you that extremely high doses of caffeine can have an impact on one’s mood, ability to sleep and feelings of general well-being. The effects are particularly pronounced if the dosages are taken in a short period of time – rather than spacing them out. The presence of other compounds other than pure caffeine can also have an impact. Flavoured milks, for example, have high doses of sugar in them – welcome to a cycle of highs and lows that is very, very unpleasant. Let’s not even talk about the impacts of ‘energy drinks’.

The results:

Once I had figured out that I was doing very bad things to my body and mind, I settled back into a routine that more closely resembled that which science suggests. I found that two cups of coffee (not espresso shots – that’s something else entirely), was enough to give me enough of a kick to be able to do the kinds of work that is involved in late-stage thesis writing/editing. I was able to chase down all the issues with my referencing and I was able to make sure that my arguments made sense (Note: this is different to the creative work in arriving at the argument in the first place). I was able to put in the very late nights required to get.it.done. In short, it seemed to work.

I’m not convinced, however, that it was/is sustainable. I now only use this particular technique sparingly. In fact, I can get more done when I deliberately slow down. More rest, longer walks and more frequent breaks seems to have a positive impact on my productivity beyond what messing with my brain with caffeine does.

*YRMV – (your results may vary)