Think You’ve OD’ed? Short Term Effects of Caffeine

Written by Orlaith Costello

Caffeine, the world's number one drug of choice. You probably don't realise that you're partaking in the human race's favourite brain-altering psychoactive substance when you're sipping on your morning flat white or cup of REIZE before the gym, but you are. Why do we humans love this delightful chemical so much? Is it more than just a pick-me-up? What are the short term effects of caffeine? Let's discuss.

What is Caffeine?

Caffeine (C8H10N4O2)  in its purest form is a bitter white powder, not unlike cocaine. And in that form, it has a slightly wordier name: Trimethylxanthine. Try saying that three times fast.

Caffeine is naturally produced in a number of plants across the globe. Most commonly found in the glorious coffee cherry seeds (a.k.a. coffee beans). It evolved coincidentally across most continents. Scientists originally theorised that it evolved as a pesticide to protect plants from their predators, this theory is now being revised as it turns out, some bugs love it just a much as humans do.

What are the Short Term Effects of Caffeine?

In humans, caffeine effectively tricks the brain into thinking it is not tired. This happens because caffeine looks almost exactly like a molecule that is naturally present in our brain, adenosine. Your nervous system is actively monitoring adenosine levels through receptors. Normally when adenosine levels reached a certain point in your brain and spinal cord, your body will begin to fall asleep or start getting tired. Because caffeine looks like adenosine, it can bind to the same receptors, preventing adenosine from letting you know you are tired. Therefore, you stay alert and focused for longer. 

As Joseph Stromberg writes for the Smithsonian, "Caffeine can fit neatly into our brain cells’ receptors for adenosine, effectively blocking them off..., thereby generating a sense of alertness and energy for a few hours. Additionally, some of the brain’s own natural stimulants (such as dopamine) work more effectively when the adenosine receptors are blocked, and all the surplus adenosine floating around in the brain cues the adrenal glands to secrete adrenaline, another stimulant. For this reason, caffeine isn’t technically a stimulant on its own... but a stimulant enabler: a substance that lets our natural stimulants run wild." 

Are the Short-Term Effects The Same For Everyone?

Because caffeine is a chemical, and we are all just a bunch of chemicals making our way through the world, our bodies react to different substances in different ways. For instance, your friend might be allergic to peanut butter but you love it so much that you have considered forsaking all other foods for it. The peanuts themselves aren't 'wrong', 'evil', or 'bad', they just affect your friend in a different way. It is the same for caffeine. Some people are sensitive to its effects and so may experience the effects of caffeine to a more extreme extent than others.

So you’re happy, alert and aware. However, it won’t refresh you, it can’t undo a week of long nights and early mornings. It can give you a boost in the moment when you need it most. But eventually, you will need a good night of sleep to properly recharge.

side effects of caffeine

What Are the Most Common Side-Effects of Caffeine?

The effects will vary, in length and strength of the effect, from person to person, depending on genetics, other physiology factors, and tolerance. Many other factors can impact the effects of caffeine, meaning you should learn how it affects you personally, as what is right for you, may be wrong for your neighbour. Usually, the main side effects of caffeine are improved alertness, better reaction time, faster recall, better memory retention, more energy, increased physical performance and stamina, increased heart rate, increased body temperature, improved mood, and lastly an increased need to urinate. However, it's good to remember that everyone reacts differently

Although the effects on someone's heart rate and stamina are not in doubt, there is some debate on whether caffeine will improve your physical performance. It is considered a banned substance at many sporting events. But, in a recent double-blind, repeated-measures, cross-over designed experiment of seven resistance trained and seven non-resistance trained male subjects found that athletes might just need to believe they had caffeine for their performance to improve. They observed an improved performance of weightlifting in untrained individuals that received caffeine and those that received placebos. Plus, they observed no improved performance in trained individuals. Meaning that caffeine may be beneficial for improving performance in resistance training when you first begin weightlifting. But once you know what you're doing, it's all in your mind. 


What are the Most Common Forms of Caffeine?

Just look around your home. Caffeine can be found on the ingredients list of many foods and household products. Including coffee, tea, most energy drinks, soft drinks, painkillers, chocolate bars, protein bars, face masks, moisturisers, and more.

Energy drinks in Australia are strongly regulated and must comply with the Australia New Zealand Food Standards Code. Some contain up to 80mg of caffeine per 250ml, the same as a cup of instant coffee. This means that the majority of energy drinks contain the same, or lower, levels of caffeine as a cup of instant coffee. And less than half the levels found in a standard espresso. Other ingredients included in energy drinks have other stimulating effects or can heighten the effects of caffeine, like taurine and ginseng

Can You Overdose on Caffeine?

Just like any other psychoactive drug, you can overdose on caffeine. That's why energy drinks have to have a recommended daily dosage on the label. And often recommend to not be consumed by children younger than sixteen years old. This is because, as I mentioned above, caffeine affects different people in different ways. Barbara in the office might consume six cups of coffee a day in order to make it through to hometime, but Alan might be buzzing all day from one single cup of joe. 

Excessive levels of caffeine can cause heart palpitations, nausea, vomiting, headaches, becoming delirious (be confused, have hallucinations, or be very excited i.e. 'giddy'), insomnia, nervousness or anxiety, and can even worsen cardiovascular disorders. They can make underlying conditions like anxiety disorders and heart conditions worse. But again, it's different for everyone.

Can You Kick the Caffeine Habit?

Absolutely. If you feel that caffeine doesn't have a great effect on you, like maybe you are having difficulty sleeping or you have increased anxiety, caffeine is actually relatively easy habit to kick. You only need to get through about 7-12 days of symptoms without consuming any caffeine. During that period, your brain will naturally decrease the number of adenosine receptors on each cell, responding to the sudden lack of caffeine ingestion. If you can make it that long without a cup of joe or an energy drink, the levels of adenosine receptors in your brain reset to their baseline levels, and your addiction will be broken. You might not be the most pleasant person to be around.  Your mood levels will be affected (due to decreased dopamine). Plus, you will experience headaches and probably a little dehydration. But afterwards, you'll be good as new!