Pain & Your Body’s Alarm System


Kerri Laurenza, SPT


Have you ever wondered how you developed a bruise on your leg and couldn’t recall how you injured yourself? Or why you may experience more pain than your peers following a similar injury? This is because 100% of pain is produced by the brain. Pain is a real experience; however, one’s perception of pain may be impacted by fear, mood, age, emotion, etc. causing individualized pain experiences. Pain is a complex symptom that may alter the way you move, think, process information, and behave.


How you perceive pain is similar to how your brain produces sound and sight. Your ears contain vibration receptors that your brain perceives as sound. Your eyes contain light receptors that your brain perceives as sight. Sound and sight are produced and altered based on the intensity and frequency of the stimuli. Think of the white/gold vs. blue/black dress that “stumped the internet.” People perceived the dress as different color schemes.


In a similar manner, all tissues contain “pain” receptors, called nociceptors. If there is a threat of injury or inflammation, nociceptors send signals to the brain. Think: the receptors have “tripped the alarm,” notifying your brain that there is a threat. Your brain then initiates a behavioral response such as pain or avoidance. If you are walking and step on a nail, the nociceptors in your foot send a signal to your brain, initiating a behavioral response, such as pain, picking up your foot, and tending to your injury. Over the course of the next few days, as the tissues heal, the pain remains as a protective behavioral response while the alarm begins to shut off.  If the stimulus does not reach the threshold (not great enough of a threat), your brain will not initiate a behavioral response. If you bang your leg on a coffee table during your favorite team’s game, your brain may decide that the events during the game are more important to attend to, or a “greater threat” than the injury to your leg.


For 1 in 4 people, the activation of the alarm will result in a hypersensitive nervous system, decreasing the pain threshold. As a result, they will have a lower threshold to pain and may continue to experience pain long after tissues have healed. Meaning, a non-harmful sensation such as light touch may trigger the alarm in a similar manner to someone else stepping on a nail. It’s important to retrain your nervous system to respond only in the presence of harmful stimuli. This will improve activity tolerance, decrease overall pain, and begin to assist with restoring function.