What is Pain?
…Pain warns us of potential harm or damage and motivates us to take action to protect ourselves. The anatomy and physiology of pain involve intricate processes that allow our bodies to detect, transmit, and interpret pain signals. Pain is multifactorial in that it is impacted by physiological mechanisms, psychological factors, and social contexts. Each contributes to the individuality of the pain experience.
Central and peripheral nervous system of the human body consisting of the brain, spinal cord, and peripheral nerves
Pain perception begins with specialized nerve receptors called nociceptors. These receptors are found throughout the body, including the skin, muscles, joints, and internal organs. Nociceptors can respond to various types of stimuli, such as thermal (heat or cold), mechanical (pressure, touch, vibration), and chemical stimuli. Some nociceptors are specific to noxious (painful), high-intensity stimuli, while others are non-specific and can respond to both noxious (painful) and non-noxious (non-painful) stimuli.
When a stimulus surpasses a certain threshold, nerve endings generate electrical signals that travel along the nerve fibers to the spinal cord. In the spinal cord, these signals connect with various nerve fibers and pathways and then ascend to the brain (seen below). The electrical-related activity spreads to different brain regions where the stimulus is processed, localized, and given emotional and motivational qualities.
Pain discernment comes from stimuli that pass the body’s threshold for stimulus intensity. The pain experience is subjective and can vary between individuals. Factors like genetics, past experiences, emotions, and cognitive processes can influence how we perceive and react to pain. This phenomenon is called the biopsychosocial model of pain (seen below) and it discusses how the true state of a person’s health can be captured by the intersection of the categories of the biological, psychological, and social domains. Social contributions relate to any interactions that an individual has with others and the roles a person plays in their social world.
As evidenced in the following graphics, pain can protect the body from loading past your tissue tolerance, thereby protecting from injury. However, the aforementioned factors can alter your body’s response to activity and make your pain system extra sensitive to movements. These movements or activities may not be damaging to your body even though your body senses pain. The relative decrease in stimulus intensity can elicit similar pain responses to high stimuli prior to injury or prior pain experience.
In practice, a common way to grade pain is either with a numeric rating scale or visual analog scale. With a numeric rating scale, a person rates their pain from 0 to 10 with 10 being the most intense pain possible. Visual analog scales allow a person to match what they feel to faces that represent pain levels. At THE LAB, we use numeric rating scales to assess, modify, and progress training programs.
Overall, pain is a crucial component of our body's defense system and survival. It serves as a warning signal, prompts protective behaviors, and can even act as a call for help. Much like an alarm system for a house, pain alerts you to potential tissue damage (alarm sounding for someone breaking into your house). However, the sensitivity of your alarm system can change depending on past pain experiences, prior injuries, emotions, and your specific belief system (biopsychosocial model of pain). This ‘alarm system sensitivity’ and pain experience can be influenced and improved in many ways; to learn more, read the next blog on how to manage pain.
Born and raised in Stoughton, MA, Zach’s passion for sports began at an early age, playing soccer throughout his childhood and during his undergraduate studies at Ithaca College. After completing his undergraduate degree, Zach continued his education, achieving a Doctorate in Physical Therapy. During this time, he also conducted extensive research in the field of biomechanics, leading to a presentation at the World Congress of Biomechanics in Dublin, Ireland in 2018. Since completing his academic career, Zach has dedicated his professional life to working in the sports science and physical rehabilitation realms, honing his skills in movement analysis, injury rehabilitation, manual therapy, therapeutic exercise prescription, and return to sport facilitation. Zach’s deep understanding of human movement and biomechanics, coupled with his passion for sports and personal fitness, make him an ideal partner for anyone seeking to improve their health, wellness, and performance.