Caffeine
Caffeine is one of our favourite drugs. If we are tired, caffeine is there to save the day.
A good, strong, caffeinated cup of tea or coffee, an energy drink, a glass of Coca Cola, or even a bar of chocolate, can give us a nice boost of energy when we need it.
We have it first thing when we get up to perk ourselves up for the day. We have it in the afternoon to lift ourselves out of a foggy slump. We have it before a workout to boost our motivation. We have it to stay alert at night if we need to study or work late.
How does it give us this surge of energy if we are flagging?
Caffeine is a stimulant, it works by activating the adrenal glands to secrete the stress hormones adrenalin and cortisol (1). These stress hormones increase the amount of sugar in our bloodstream, by drawing on stores from our liver. This burst of available sugar gives our energy a boost.
Caffeine also blocks the chemical adenosine in our brain, which overrides tiredness and increases the effect of the neurotransmitter dopamine, which improves focus, alertness and motivation (2).
However, what goes up, must come down.
Caffeine temporarily increases blood sugar, cortisol, adrenaline, dopamine and blocks adenosine, but when the effects of the stimulant drug wear off, our blood sugar, stress hormones and dopamine levels reduce, causing a rebound of tiredness and we are back to the starting point. That is when we reach for some more coffee, tea, cola or chocolate to boost ourselves back up.
Over the long run, we can build tolerance to the stimulating effects of caffeine, so like a drug, we need more and more of the chemical to get the same effect. If we try to stop caffeine cold turkey, we can experience withdrawal symptoms, like headaches, depression, irritability or tiredness. So we keep reaching for the caffeine and stay stuck in the addictive cycle (4). It is an illusion that regularly drinking caffeine gives you more energy or makes you feel more alert, in fact if you are addicted to caffeine, the stimulatory effects only reduce withdrawl symptoms to take you back to your natural, base line levels of energy.
However, because it is a central nervous system stimulant, excessive use of caffeine can cause anxiety, palpitations, diarrhoea, fatigue or insomnia (3), so if we are experiencing any of these symptoms, it might be sensible to think about the balance between caffeine’s temporary boost, versus the longterm effects on our energy, mood and wellbeing.
To stay within safe limits, the recommendation is to have no more than 400mg of caffeine daily, which is about the equivalent of up to three cups of coffee daily (5), but people vary in how sensitive they are to the effects of caffeine.
If you think you might be addicted to caffeine and the payback might be higher than the payoff, I suggest starting to reduce the amount of caffeine you are consuming gradually, to avoid strong withdrawal symptoms. This might look like swapping one caffeinated coffee or tea for a decaf daily, until you can reduce to one cup of caffeine daily. This way, you can still keep the ritual of a cosy cup of tea or an uplifting cup of coffee in your day, whilst taking care of your wellbeing in a way which works for you.
https://www.verywellmind.com/caffeine-stress-and-your-health-3145078
https://pmc.ncbi.nlm.nih.gov/articles/PMC6758129/
https://www.ncbi.nlm.nih.gov/books/NBK519490/
https://pmc.ncbi.nlm.nih.gov/articles/PMC3777290/
https://www.fda.gov/consumers/consumer-updates/spilling-beans-how-much-caffeine-too-much