We are creatures of habit, and with the UK population drinking around 98 million cups of coffee a day, our infatuation with the morning brew is hard to beat. Currently the most consumed psychoactive substance in the world, caffeine has been reported to not only keep us feeling energised, but also to positively affect our mood and general health.
Having just been plagued with a bout of the fifth week blues myself, a drink that can both help me finish a problem sheet and put a smile on my face is very appealing.
The key to unlocking the full benefits of coffee is not as simple as knocking back several double shots a day, however (especially for any sleep-deprived and overworked student).
Despite differing views within the scientific literature on the effects of caffeine and the optimal dose, some common threads shine through on how those 98 million cups can have their maximum impact.
So how does it work?
Fellow coffee fiends may be disappointed to find out that coffee is somewhat of a trickster. That buzz we get is not from any real energy boost, but instead from caffeine’s ability to fool our body into ignoring signals that we are tired.
As you use energy throughout the day, a chemical called adenosine starts to build up. Adenosine binds to cells and promotes sleep by telling cells to slow down. The active ingredient in coffee, caffeine, binds to adenosine receptors (molecules on the cell surface that allow them to respond to signals) and prevents adenosine from attaching. This leads to the feeling of alertness associated with drinking a strong coffee.
Frustratingly, the deceptive nature of a Cup of Joe means we are under the illusion of having more energy than we do. Once coffee stops having its effect, we are hit with the full force of any energy deficit. Unfortunately, the only real way of getting back our energy is to sleep.
Surely the way to combat this is just to drink more coffee? Well… yes, but also no. This may delay the post-coffee slump but comes with serious health drawbacks. Excessive caffeine consumption limits and even reverses the benefits of drinking it in the first place. It has been reported that high doses of caffeine can promote anxiety and cause further sleep deprivation as well as gastrointestinal symptoms. Based on this, the FDA recommends that people do not exceed 400mg of caffeine (approximately four cups) a day.
Once coffee stops having its effect, we are hit with the full force of any energy deficit.
How do we make the most of our coffee habits?
It is not uncommon for students to report chronic sleep deprivation, with studies showing we achieve around six hours of sleep a night – much below the recommended 8-10 hours. Resting is often sacrificed as students attempt to balance work, exercise, and an active social life – therefore, maximising the energy boost from coffee whilst avoiding the negative side effects of drinking too much would be the dream.
When the time is right
Despite the popularity of a coffee with breakfast, this may not be the most effective time to consume it if you want to achieve maximum alertness. Whilst you sleep, adenosine levels decrease, meaning coffee seems less potent first thing in the morning. In addition, cortisol (which caffeine acts to increase) levels are high after waking and then drop throughout the day. It may therefore be beneficial to have your first shot of espresso in the late morning. Further evidence for switching up your morning coffee is that food can slow caffeine absorption, making it a poor breakfast companion.
The question of when we should drink coffee to achieve maximum alertness is not a new one. In fact, it is essential to occupations that require fast reaction times. For this reason, US Army researchers developed an algorithm that could predict the optimal dose and timing of coffee consumption throughout the day based on a person’s history of caffeine intake and sleep. Working in the army means soldiers need to be able to respond quickly in emergency situations while often running on less than 5 hours of sleep a night. To help combat this, researchers created the 2B-Alert Web tool, which designs a caffeine schedule unique to the individual to ensure that alertness never drops below a certain threshold despite sleep deprivation. Crucially, the tool demonstrates that by timing it right, a person could decrease their caffeine consumption by 65% (thereby avoiding any negative health effects) whilst still reaching the same level of alertness. The pitfall of algorithms like this is that they are based on population averages and don’t take into account all the variables that may influence a person’s reaction to caffeine, so although their recommendations are useful, they may not be right for everyone.
Pick your poison carefully…
Not all coffees are made equal. A recent study by Which? evaluated the amount of caffeine in coffees purchased from several high street chains and noted significant differences, with some of the highest scoring contenders containing up to six times as much of the psychoactive ingredient as the lowest. Differences like this makes it hard for the average person to measure their daily caffeine intake in cups, with the 400mg limit being hit by anything from 2 to 5 cups depending on where you get your java. If you want to feel the buzz without overdoing it, you need to choose where you get your cuppa wisely.
Some of the highest-scoring high street coffees contain up to six times as much of the psychoactive ingredient as the lowest.
It’s all about… you
The overriding factor in determining how we respond to caffeine (or any drug for that matter) is the individual. Particularly when it comes to coffee, previous coffee habits and genetics are two of the main factors contributing to how energised we feel after an espresso. Several genetic variants in the genes responsible for caffeine metabolism and the adenosine receptor affect how quickly we process and respond to coffee. This means some people may be able to bypass the “no coffee 6 hours before bed” rule if they rapidly process any coffee consumed; others, however, may get jittery after a single shot.
The question of whether there is a right way to drink coffee remains unsolved. We can speculate about the optimal time and dose of caffeine, but no single answer will apply to the entire population. Perhaps the most disappointing answer of all is that although we can trick our body into thinking it is awake, the only real way to feel more energised is to have enough sleep.
Regrettably, it is sixth week and a flurry of essay crises awaits me – I think I’ll stick to the espresso.