Many of us have this false belief that coffee gives you energy and have an expectation that it will wake us up. That’s not entirely how coffee works. We might perceive the experience as newfound alertness but, the reality is that caffeine is just hiding how tired we really are. It’s like a painkiller but for tiredness.

Why do we feel tired to begin with?

As we go about our normal day we release the sleep inducing molecule called adenosine. Neurons in our brain have receptors tailored to adenosine (i.e. adenosine receptors). When adenosine attaches to these receptors it makes us feel more sluggish, slows us down and makes us sleepy. It also decreases our motivation or anticipation by blocking dopamine. This process is to encourage sleep and as you sleep adenosine declines gradually promoting wakefulness.

How does caffeine work?

Caffeine has a very similar molecular structure to adenosine but does not activate adenosine receptors. It can block the receptors from adenosine but does not make us feel sluggish and allows continued uptake of dopamine. Caffeine slowly breaks down over time allowing adenosine uptake. Caffeine also stimulates adrenaline (fight or flight) for heightened alertness.

Why is this all bad?

To put it plainly, caffeine stops you from recognising how tired you really are and then on top of this creates a physiological stress response. Caffeine raises heartrate and blood pressure, is diuretic (increases urination and diarrhoea) and can contribute to insomnia and anxiety. If caffeine is blocking adenosine, your body will adapt and create more adenosine receptors. This can lead to habituation and dependency. If you stop drinking coffee, these excess receptors result in unpleasant withdrawal symptoms such as headaches, tiredness and low motivation/depressed mood. Without caffeine in your system these receptors will decrease back to a regular amount.

If you wake up feeling exhausted prior to having a coffee, this is the underlying state of your body all day.

As soon as you have that morning coffee you hide how tired you really are. Going about your normal day with a coffee instead of resting is like taking a painkiller and then re-injuring yourself because you can’t feel that it hurts. Most of us do this daily.

Do I drink coffee?

Yes, but in moderation. I only drink coffee during the week and dishabituate over the weekend. I don’t drink coffee first thing in the morning. Upon waking we have low levels of adenosine receptor activation and high levels of cortisol. This is the least effective time to have coffee. Having coffee too late can impact on sleep, upto 6 hours before bed time can impact on sleep quality. Some research has suggested between 9:30am and 11:30am is ideal because that is when our cortisol has a natural dip. To make caffeine more effective I drink coffee closer to the later time.

What else can be done to stay alert instead?

You might consider a slower release of caffeine such as green tea or bullet proof coffee (coffee + fat) but the best solution is more high-quality sleep or an afternoon nap. It is important to be aware that napping can result in sleep inertia (i.e. feeling drowsy upon waking).

Interested in music to help your afternoon nap?