Brain on Caffeine: How Coffee and Energy Drinks Affect Students

For many, caffeine is a lifesaver. Whether it’s a morning coffee or an energy drink in the middle of a late-night assignment marathon, caffeine is almost a daily essential. But what exactly does it do to our brain and body? And is it the study aid that students believe it to be?

How Caffeine Works

Caffeine blocks a chemical in your brain called adenosine that makes you feel tired, so your brain stays awake. But once the effect of caffeine fades, adenosine rushes back, triumphantly announcing its return, making you feel even worse than before, and there you go – a caffeine crash.

Have you ever felt like your brain is moving at a snail’s pace during lectures? Caffeine can put it into overdrive. Caffeine boosts attention, reaction time, and mood, which is why it’s a no-brainer for all-nighters. Yet, there’s a catch – dosage matters. A moderate dose of caffeine (100-200 mg, or roughly a cup of coffee) will get you going, but too much (more than 400 mg) can have you buzzing like a phone on silent mode, making it harder to focus.

The Crash: Anxiety, Stress, Sleep Disruption, and Dependence

While caffeine guarantees you stay awake, it also activates stress hormones like cortisol and adrenaline, which can turn up the volume on anxiety. The more you rely on it, the worse you sleep – creating a vicious cycle where you’re always craving caffeine to make up for lost sleep. Does this ring a bell?

Energy drinks promise laser focus and boundless energy, but come with some unwanted sidekicks – loads of sugar and stimulants like taurine. They cause blood sugar spikes, heart palpitations, and enough jitters to make typing in class a challenge. Studies even link heavy use of energy drinks to higher stress levels and poor sleep. Maybe refueling on energy drinks isn’t the best pre-exam ritual?

Your body is smart. The more caffeine you consume, the more it adapts to, and that single shot of espresso might not be enough anymore. Before you know it, you’re up to cup number five just to feel wired. And if you cut back suddenly? Headaches, fatigue, and crankiness can hit. Caffeine withdrawal isn’t a myth, and it’s no fun.

Finding a Healthy Balance

So, should students ditch caffeine altogether? Not necessarily. Experts suggest:

• Timing it right – Avoid caffeine in the late afternoon or evening to prevent sleep disruption.
• Moderation is key – Stick to recommended daily limits (about 400 mg for adults).
• Alternative boosts – Stay hydrated, consider quick naps, and movement breaks to boost alertness without relying solely on caffeine.

Caffeine can be your best friend or worst enemy, depending on how it’s used. Coffee can be a brain booster, but using caffeine as a cheat code for energy? Is caffeine really helping us to stay ahead, or is it merely sustaining us in a cycle of highs and crashes? Maybe it’s time to sip smarter.

Words by Jacqueline Wong

References:

1. Reddy, V.S., Shiva, S., Manikantan, S. and Ramakrishna, S., 2024. Pharmacology of caffeine and its effects on the human body. European Journal of Medicinal Chemistry Reports, p.100138.
2. Hennessy, N., Lead Dietitian, Cromwell Hospital. 2024. How caffeine affects your body. [Online]. 14th February 2025. Available from: https://www.bupa.co.uk/newsroom/ourviews/how-caffeine-affects-body