What's the Real Deal with Caffeine?

Friday, 15 September, 2023

Words by Katie Burnett

In the early 1900s, Barcolo Manufacturing in Buffalo New York introduced the “coffee break” to its labour force. Twice a day, the entire factory would stop to have a cup of coffee. It was a special benefit that they were able to offer their employees, and they found that it gave the workers a chance to relax, but also return to work more productive and energized. Fast forward to the typical workplace in 2023 and coffee is a massive has a massive part to play in the lives of the economically active. 

 What we know about caffeine is that it increases mental and physical performance, increases a feeling of well-being and alertness. As an avid coffee consumer, I wanted to understand more about the effects that regular caffeine intake was having on my health. What was the scientific literature indicating? Is caffeine a drug we should stay away from or is it the greatest gift to productivity since Henry Ford?

My introduction to the topic was on Andrew Huberman’s podcast. Huberman is an associate professor of neurobiology at Stanford University School of Medicine and hosts Huberman Lab, a podcast with over 3 million weekly listeners. The episode “Using Caffeine to Optimize Mental & Physical Performance” dives into the neuroscience of the effects of caffeine. 

Immediately Huberman dives into the links between caffeine and the prevention of cognitive decline in the long term. Huberman goes on to describe multiple studies into this topic, of which the outcomes were that caffeine consumption has shown to decrease risk of cognitive degeneration in later life. In 2020, scientists Chen, Scheltens, Groot and Ossenkoppele set out to summarize the data of 61 independent studies between 1990 and 2020 that explored caffeine and cognitive health. Their findings were undeniably skewed towards caffeine having a positive effect on brain function (when consumed in moderate quanitities, 100-400 mg/d).

What does that mean? An average cup of filter coffee has around 95mg of caffeine and the average single espresso has around 65mg of caffeine*. In coffee terms, “moderate quantity” sits at between 1 and 3 coffees per day.

Now that I knew how many coffees a day was “moderate”, I wanted to know if there was an optimal time to be consuming this caffeine. We are always warned against drinking coffee after 4pm to avoid it decreasing our quality of sleep. This is true. In 2016, a review was done that concluded that “slow-wave sleep and electroencephalographic (EEG) slow-wave activity were typically reduced, whereas stage-1, wakefulness, and arousals were increased”. Caffeine has a concrete negative effect on quality of sleep.

Huberman states that caffeine can take up to 12 hours to be completely cleared from the bloodstream (other studies suggest 10 hours). The Sleep Foundation notes that this can also vary from person to person, hence some of your friends can’t sleep if they drank coffee after noon and others can have a coffee after dinner and still fall asleep by 10pm. Sleep Foundation suggests avoiding caffeine consumption from 8 hours before sleep and Huberman suggests from 12 hours before sleep. Although they differ slightly, the sentiment is the same: having caffeine in your bloodstream during sleep will significantly decrease your quality of sleep.  

Caffeine has been pointed at for a few different crimes outside of sleep: increased anxiety, cardiovascular disease, liver disease. According to the Harvard School of Public Health, the studies done into these various areas have all concluded that caffeine consumption does not contribute cardiovascular disease, despite the wives tales, “cohort studies have not found that coffee drinking is associated with a higher risk of hypertension”. Similar results were concluded when examining caffeine and liver disease. In fact, “caffeinated coffee intake is associated with a lower risk of liver cancer, fibrosis, and cirrhosis”. 

Now, the big one: those anxious jitters you get after drinking coffee. The Harvard School of Public Health states that those who have “underlying anxiety or panic disorder are especially at risk of overstimulation when overloading on caffeine”. Although, you do not have to have a pre-existing condition to feel these anxious jitters and it is suggested that although some are more sensitive than others, more than 400mg of caffeine per day puts you in the red zone for those anxious feelings. 

All this information has me pleasantly surprised. To not only discover that ongoing and past studies have pointed towards caffeine being fairly harmless in moderate doses, but that caffeine has been proven to aid in the prevention of some diseases has been astonishing to me. Here, the key phrase is “moderate doses”. All of the studies hinge on the consumption of consistently moderate doses. My parents would always repeat to me as a child, “everything in moderation and you’ll be okay”, and it seems that they were more spot on than they probably realised.

* I am not a scientist and these findings are not my own, I am merely a curious caffeine consumer compiling information from various reputable studies and individuals. If you would like to read more about the studies discussed, please find the links below.








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