With over four hundred billion cups of coffee consumed each year, caffeine is by far the world’s most widely-consumed psychoactive drug. For many of us, a hot cup of coffee proves to be a powerful and potent stimulant — a necessity to start the day. But caffeine’s effects vary significantly from person to person, and its actual effects on productivity remains unclear. Beyond anecdotal evidence, numerous studies show that, in small doses, caffeine provides an increase in energy and alertness, while improving reaction time and cognitive performance. But is coffee really making you more productive?
What does the research say?
The effects of caffeine on productivity have been a topic of considerable academic interest — researchers at Johns Hopkins University recently found that consuming small amount of caffeine can have a positive effect on long-term memory. In a double-blind trial, participants were given either a 200-milligram caffeine tablet or a placebo, and were asked to study a series of images. The next day, both groups were shown a new set of images, including pictures that were visually similar to the previous — the caffeine group was better able to identify these new images as “similar” rather than citing them as the “same.” In a paper published in Nature Neuroscience, the researchers wrote that this ability to recognize the difference between similar but not identical items — called “pattern separation” — suggests that the caffeine group benefited from greater memory retention.
However, other research suggests that many of the benefits of caffeine can be replicated by placebo. In another double-blind study at the University of East London, participants were randomly given either caffeinated or decaffeinated coffee — half were told they were regular coffee, and half that they were given decaf, also at random. Interestingly, the participants who were told that they received caffeinated coffee performed better on tests measuring reaction time, self-control, and reward motivation. The researchers concluded that the relationship between caffeine consumption, mood, and performance depends on many individual psychological variables — strangely, all participants in the study reported increased feelings of depression after drinking coffee, although this increase was slightly lower in the group that received caffeine.
Research also shows that caffeine also has a complex effect on creativity. Maria Konnikova observed in The New Yorker that “creative insights and imaginative solutions often occur when we stop working on a particular problem and let our mind move on to something unrelated.” As evidence, she pointed to a 2012 study in which participants performed better in creative thinking exercises (for example, devising novel and inventive uses for an everyday object like a newspaper) after they had allowed their mind to “wander” by switching between “undemanding,” low-intensity tasks. This suggests that caffeine may assist more in very simple, repetitive tasks like checking e-mails or filling out forms, and less in jobs that require high levels of insight and creative thinking.
And, for the same reasons caffeine increases alertness and wakefulness, it also has a tendency to cause anxiety, jitteriness, and sleeplessness. Scientists at Rice University studied the effects of caffeine on sleep — they observed that a typical cup of coffee decreased the average sleep time of study participants by an average of two hours; it also increased the amount of time it took to fall asleep by thirty percent. Coffee also had significant effects on quality of sleep: the number of sleep awakenings in the experiment subjects doubled. These conclusions has been reproduced in numerous studies, and suggest a significant risk of impairing your creativity and productivity if you don’t properly manage your caffeine intake.
Many people don’t know that the human body naturally “caffeinates” itself with the hormone cortisol at specific times of day, depending on your body’s natural circadian rhythm — typically early in the morning (between 8am and 9am), around lunch time (between 12pm and 1pm), and once again in the late afternoon (from 530pm to 630pm). If you are an avid coffee drinker, you may be impairing your body’s ability to produce cortisol — by drinking coffee when it’s not needed, i.e. when your body is attempting to naturally energize itself according to its hormonal cycles, you may build a faster tolerance to it.
Test it for yourself!
All the research shows a complex interaction between caffeine and bodily cycles — so instead of relying on the abstract conclusions of large-scale studies, how can you determine the specific effects caffeine has on your body? Caffeine’s effects depends on dosage, body type, weight, age, time of day, and many other factors; so it’s best to monitor all these variables by collecting your own data. First, you need to make sure you’re collecting accurate information: here are some tools we recommend.
RescueTime records how much time you spend using computer applications and browsing web sites. It allows you to keep track of how you are spending every minute of the day, and when and how you are wasting time, and it doesn’t require any effort to set up! It simply runs in the background and stays on top of your browsing habits for you.
Jawbone UP Coffee
Jawbone UP Coffee is a great app for tracking your coffee intake — it’s a simple tool for logging your coffee, tea, and energy drink consumption, to see how it changes overtime.
Sherbit is a personal dashboard that gives you access and control of your personal data in one place. The app syncs with over twenty-five applications including Facebook, Fitbit, Uber and Withings to gather and visualize data. From there, you can identify patterns in your daily habits and correlations across multiple services. For example, if you wanted to find out if you were less active on days you worked more, you could add steps counted by your Fitbit and productivity hours tracked by RescueTime. Download Sherbit from the the App Store here.
Here are some results from our own test:
By combining the data from Jawbone UP and RescueTime, I found a correlation between caffeine and productivity. You can see this by looking at the trend lines and flipping between the tabs at the top of the chart.
However, I found an even stronger correlation with my sleep and productivity — the more coffee I drank, the less sleep I got. This seem to be true for everyday other than JuIy 22nd and July 29th, but as I looked closer I realized that I had consumed coffee earlier in the morning on those days. This may seem like an obvious conclusion in retrospect, but being able to visualize the data made the effects of coffee on my life much more apparent to me. By reflecting on my data, I realized that there’s is a dual effect on the relationship between coffee and sleep: caffeine affects my quality of sleep and reduces the length of time I’m awake… however, when I don’t get much sleep the previous night, I tend to drink more coffee the next day, perpetuating the cycle. I also noticed that my quality of sleep decreases much more significantly when I drink coffee late in the afternoon — I realized that caffeine tends to work best early in the morning, when it will have a minimal effect on my sleep that night.
Have you found interesting correlations between different data sources? Let us know in the comments below.