Touch a hot pan by accident, and you immediately pull your hand away. Hit your toe against the corner of a table, and for a few seconds, you hate everything… A toothache wakes you up in the middle of the night, and you discover that one tiny tooth can take control of your entire life…
Pain is one of the most unpleasant parts of everyday life. It interferes with our ability to work, sleep, move and sometimes even think. So it is natural to ask: why does this agonizing sensation exist?
The answer is paradoxical: life without pain would be far more dangerous. In fact, there are people who have been unable to feel pain since birth, and this condition poses serious challenges for them.
Why doesn’t the brain let us touch a hot pan without reacting?
Let’s go back to the hot pan. As soon as we touch it, specialized nerve endings in our skin, called nociceptors, respond to the dangerous temperature.
They generate electrical signals that travel along nerves to the spinal cord, which then relays the information to the brain. It is through the brain’s involvement that the unpleasant sensation we call pain is produced.
There is one interesting detail here: we often pull our hand away before we have fully registered the pain.
This is thanks to a spinal reflex. The body does not wait for you to analyze the situation, assess the pan’s temperature and decide that pulling your hand away is a good idea.
Neural circuits in the spinal cord activate the relevant muscles, causing your hand to withdraw. In other words, by the time you consciously register the pain, your body has already launched its own survival operation.
Why does something sometimes hurt more than it should?
Stubbing your toe against a piece of furniture can hurt as if you have suffered a serious injury. Yet nothing may be broken, and the pain can disappear within minutes.
That is because pain is not an accurate measure of how severe an injury is. Its perception is influenced by attention, emotions, past experiences and the surrounding environment.
For example, a football player may sustain an injury during a match and initially feel almost no pain. Only after the game ends might they realize that the injury is quite serious.
During intense emotional arousal or stress, the brain can temporarily reduce the transmission of pain signals. The opposite can also happen. When we are anxious, sleep poorly or constantly focus on pain, we may experience it more intensely.
Pain is a real experience, but its intensity is regulated by the nervous system.
How can an arm that no longer exists still hurt?
One of the strangest phenomena associated with pain is phantom pain.
A person who has lost an arm through amputation may still feel as though their fingers hurt, their fist is clenched or their wrist is under intense pressure.
How can a body part that no longer exists still hurt?
The explanation lies in the fact that the brain has a kind of neural map of our body. It represents different body parts and processes the sensory information received from them.
After a limb is lost, this neural system does not disappear immediately. Processes occurring in the brain, spinal cord and remaining nerves can still produce the sensation of pain.
This shows that pain is not simply a signal originating from damaged tissue.
There are people who have never felt pain
Imagine a child who falls, badly injures their knee and continues playing as if nothing happened… Or someone who touches hot water and only notices the burn once their skin has already been damaged.
Such cases really do exist.
Due to rare genetic conditions, some people are born unable to feel pain. One such condition is associated with certain mutations in the SCN9A gene, which disrupt the functioning of neural mechanisms essential for transmitting pain signals.
At first glance, this might seem like a superpower. In reality, the condition can be life-threatening.
Children may accidentally injure their tongues, break bones or suffer severe burns without pain warning them of the danger.
In some cases, injuries are only discovered after serious complications have already developed.
Why does pain sometimes persist even after an injury has healed?
Pain has another unusual characteristic: sometimes it remains even after the danger has passed.
For example, a person may injure their back, the tissues may gradually heal, yet the pain can continue for months.
Pain that lasts for more than three months or recurs over time is known as chronic pain.
In some cases, this is caused by increased sensitivity of the nervous system.
Imagine a fire alarm that was initially triggered by a real fire but then became so sensitive that it starts sounding even when exposed to ordinary steam.
This is a useful analogy for understanding some forms of chronic pain, although chronic pain can have many different causes.
Why do we need pain?
The main evolutionary advantage of pain is its ability to help us avoid danger.
If you burn your hand on a hot surface once, you will probably be more careful next time. If you injure your foot, pain encourages you to put less weight on it and give it time to recover.
Pain also plays a role in learning. It helps us remember dangerous experiences and avoid similar situations in the future.
Of course, this system is not perfect. Sometimes pain is excessively intense, and in cases of chronic pain, it can even lose its protective function.
Ultimately, pain may be one of the most unpleasant mechanisms in our bodies, but it is also one of the most useful.
It is an alarm system that we often wish we could switch off, yet without it, we would face far greater dangers.
