Caffeine is the world’s most often ingested psychoactive substance, and it’s found most commonly in tea, coffee, and chocolate. An alkaloid found in many different plants, caffeine is a minor stimulant that affects the central nervous system and is often used as a supplement to fend off sleepiness and improve focus. However, could it be that your coffee (or more directly, a caffeine supplement) can help reduce pain? And if so, what kind of pain? And how?
How Caffeine Works in the Body
The way caffeine functions on the body begins with its ingestion. While caffeine is a common ingredient in energy drinks, caffeine doesn’t really give you more energy per se. What it does instead is block off natural neurotransmitters that help your body power down. In other words, it allows us to access energy that’s already there, but gated off. If used irresponsibly, this can help contribute to a caffeine crash. We derive energy from glucose, which is used up by our cells in the production of ATP and won through our diet.
But as the day goes on, and our neurons continuously work their usual 16-hour shift, a neurotransmitter (brain chemical) called adenosine is being continuously released into our system. Because neurons are cells, they possess receptors that pick up certain molecules that are shaped just right, in order to trigger different functions. Adenosine receptors pick up the free adenosine in our system, until enough of it is accumulated that the body begins to signal to us that it’s time to sleep.
During this process, we generally feel drowsy and calm, and slowly prepare to fall asleep. This is part of how the body keeps an internal clock (our circadian rhythm). The other chemical responsible for the slow descent into sleepiness is melatonin. While adenosine is a byproduct of our neurons working hard throughout the day, and is used as a neuromodulator to prepare for sleep (and other things), melatonin is produced by the pineal gland, building up throughout the day, draining out of the system during sleep, and building up again the next day.
Melatonin is blocked by light. Blue light (the kind generated by screens, for example) is especially potent, as it’s closest to sunlight, and thus keeps us awake. Adenosine, on the other hand, is blocked by caffeine (and other stimulants). Caffeine achieves this by being similarly shaped to adenosine, and thus blocking adenosine from attaching to its respective receptors by taking precedence over the neuromodulator. Until the body metabolizes and clears out the caffeine, it continues to fool the body into thinking that it isn’t time to fall asleep just yet.
Blocking adenosine is caffeine’s primary function in the body and brain, but this does more than just stop drowsiness. As our neurons no longer recognize adenosine during the period wherein caffeine is active in our system, they begin to speed up. Meanwhile, because adenosine also regulates vasodilation (the opening up of blood vessels), our blood vessels begin to constrict, increasing blood pressure.
As our neurons fire more rapidly, an automatic effect within our central nervous system triggers the release of adrenaline, in response to the fact that we’re suddenly in what feels like an emergency. This release of adrenaline is what causes many of the physical effects of ingesting enough caffeine, from a faster heartbeat to better blood flow in the muscles, dilated airways, and a burst of energy as our liver’s glycogen stores are made open for depletion.
Joining Forces With Caffeine to Fight and Reduce Pain
Pain is a complex sense, generally understood to be a warning by the body that something isn’t going the way it should be. At other times, pain can be chronic and debilitating, serving no positive purpose. Sometimes it’s a bit of both. While the boost in adrenaline can go a long way to help reduce pain, the main mechanism by which caffeine helps reduce pain is through its relationship with adenosine. As mentioned previously, caffeine leads to vasoconstriction.
This can help alleviate headache pain, which is why caffeine is often paired with acetaminophen for over-the-counter vascular headache relief. Because caffeine increases blood pressure, it also boosts the speed at which medicines become effective, making it a good pick to mix with other over-the-counter drugs. Not only does this mean your painkillers kick in faster, but they can also be more effective. Studies show that caffeine helps drugs like ibuprofen and paracetamol be 5-10 percent more effective at relieving pain.
Adenosine also plays a role in pain perception, which means that caffeine helps reduce the way the brain perceives pain, while boosting the production of dopamine, which acts as a natural painkiller. Finally, it’s important to note that sleepiness and sleep deprivation are linked to increased pain perception. This is caffeine’s double-edged sword – it can alleviate the pain-boosting effects of feeling tired by making you less tired, but it’s only a temporary solution. A more effective approach would be to get more quality sleep.
The Bottom Line
When used effectively, caffeine allows you to ‘ride a wave’ of positive effects. The release of adrenaline and blocking of adenosine allows for a state of heightened alertness and greater physical ability, while helping with minor pains, and even specifically targeting certain pains, such as headaches and joint pain. However, with a caffeine high comes a caffeine crash. Once caffeine wears off, and the adrenaline rush is over, your body and mind feel the toll of using the drug.
Most of this is easily fixed with a long sleep session, but that’s exactly where being careful with caffeine becomes so important. If taken too late in the day, caffeine can greatly affect your sleeping habits, to the point that you are unable to fall into a deep sleep until much later in the evening. If you other issues with falling asleep, or have previously struggled with insomnia, then having any coffee in the afternoon is a bad idea. The half-life of caffeine is roughly six hours, which means that by six hours, half of the caffeine you will have ingested will have been metabolized.
If you have coffee in the afternoon, your body will still have caffeine in it by the time you lay down to sleep. This will leave you feeling tired and depleted the next morning, pining for another cup. This cycle of sleep deprivation can greatly affect your physical performance, and pain sensitivity. When dosed and scheduled properly, caffeine can be a great tool both for alertness and for pain. But if it begins to affect your quality of sleep, then it’s time to wean off the caffeine and quit for a while.