What is Pain?

Understanding the human body can be very helpful for athletes in any sport. A particularly fascinating phenomenon concerning the human body is the idea of pain. 

Pain is an extremely ambiguous term. One definition of pain could be a complex, biopsychosocial phenomenon characterized by several cognitive and affective processes, leading to interactions between various neurochemical and neuroanatomic systems. But pain could also be defined as a sensory or emotional feeling caused by tissue damage, causing an unpleasant feeling. Thus, the ambiguity of pain leads the topic to be one of the most questionable areas of study amongst researchers today. 

Biologically speaking, pain is essential for humans. Two important uses for pain in humans include the external aspect where pain (in the form of the human sense touch) is used to pinpoint and escape threats and the internal aspect where pain is utilized to identify and protect injured tissues which disrupt the normal bodily processes. 

Secondly, nociception is a process led by a series of events used to process information derived from external stimuli. Nociception is a major subset of pain, and it makes up a lot of how individuals perceive pain. This process begins at specific pain receptors (nerve endings) in body tissues that respond to damaging or potentially damaging stimuli. At the molecular level, nociception occurs through intra- and extra-cellular molecular messengers, leading to signal transduction down nerves in the nervous system. In order for nociception to begin, there must be a thermal stimulus (with a temperature above 40°C), mechanical stimuli (where extreme pressure is concentrated over a small area), and/or chemical stimuli (like strong acid or alkali) that comes into contact with the human. When the noxious stimulus is received, the human’s nociceptors become activated. 

Nociceptor activation is influenced by inflammatory mediators which are synthesized at the site of the individual’s initial injury. These mediators are often titled “inflammatory soup”, as they consist of peptides, neurotransmitters, lipids, and neurotrophins. Two possible outcomes stem from the presence of these inflammatory mediators: the first of which excites the nociceptors near the inflammatory soup and the second lowers the nociceptor’s activation threshold. Once the nociceptors are activated, an electrical signal is sent down a nerve fiber attached to myelinated Aδ and unmyelinated C fibers, leading to the dorsal horn and the activation of a process called neurogenic inflammation. 

The outcome of the neurochemical changes previously listed in the local environment of nociceptors results in the increased activation of Aδ and C fibers. Once the signal is received in the second-order-pain transmission neurons of the spinal cord, it is then forwarded from neuron to neuron using the excitatory neurotransmitter glutamate to specific pathways in the brain. One of these areas is the thalamus, which organizes all the information received and relays it to other locations in the brain. These other, specific locations include the limbic system (connected to emotions), the somatosensory cortex (connected to physical sensation), the insula and anterior cingulate cortex (connected to the perception and subjectiveness of pain), and the frontal cortex (connected to thinking). 

As stated before, nociception is a subset of pain perception. The level of nociception that allows the process to be categorized as pain perception is when stimulation of nociceptors is at the degree to which Aδ fibers begin to become activated, leading individuals to experience a sharp and prickling pain. When the strength of stimulation increases, C fibers are implemented into the process, leading to a burning sensation that lingers after the cessation of the initial stimulus. These sensations are often seen in individuals that have recently had an acute injury or trauma. Two other types of pain called fast pain and slow pain branch off this field of nociception. Fast pain is the type of pain that is felt after a damaging incident, occurring almost immediately after the stimulus is received and interpreted. This pain is not necessarily intense, especially when compared to the second variation. Slow pain is felt for a long period of time after the initial stimulus is received, and medical professionals describe slow pain as more unpleasant and less discretely localized than fast pain. Nociception is responsible for both fast and slow pain. 

Other types of pain include neuropathic pain, psychogenic pain, acute pain, and chronic pain.

Neuropathic pain is a type of pain that derives from injury to the system that carries and interprets pain, like the nerves, spinal cord, or brain. Patients with this type of pain experience burning, tingling, or shock-like sensations throughout the body. In addition, patients who have neuropathic pain may have increased sensitivity to external stimuli, causing things that are not usually painful to cause pain. This phenomenon also causes painful stimuli to be perceived as even more painful. Processes that often cause neuropathic pain include physical damage to nerves, the inability of the spinal cord and/or the brain to dampen down the received pain, and increased concentrations of glutamate between nerve synapses.  One variance of neuropathic pain is commonly associated with shingles, a skin condition caused by the varicella-zoster virus, and this leads to an inflammation of nerves, which often establishes a constant tingling, aching, or burning sensation in patients. Lastly, neuropathic pain is quite common, occurring in 10% of adults over the age of thirty.

Psychogenic pain is a type of pain that worsens because of existing physiological factors. Individuals with psychogenic pain perceive pain in an intensified manner, considerably out of proportion to the perception of normal individuals to the same exact stimuli. This is one example of how pain can occur without noxious stimuli, a phenomenon being extensively studied . Some possible treatments for psychogenic pain include the use of non-narcotic painkillers, antidepressants, and psychotherapy. 

Prior to its classification, medical officials have estimated that millions of people in the United States have suffered from acute and chronic pain. Acute pain is a short-lasting variance of pain that serves as a warning that damage is occurring. This type of pain goes away shortly after the initial experience, usually when the injury or disease causing the pain heals. Examples of acute pain include the sensation felt when you accidentally touch your finger on a hot object or when you stub your toe on your bedroom door. On the other hand, chronic pain is longer-lasting, ongoing tissue damage. This duration time frame can range from medical institution to medical institution, but pain is classified as chronic when it lasts for more than 3-6 months. Chronic pain lasts beyond the healing of the initial injury that caused the pain, so chronic pain is classified as a disorder itself compared to being a symptom of the initial disease or injury. On the cellular level, several causes of chronic pain may be identified, such as when nociceptors and neurons becoming too easily activated, when connections in the essential neuronal pathways are altered, when parts of central nervous system fail to dampen pain signals, when nerves abnormally grow after nerve injury, or when normally inactive neurons begin to be activated. Patients with chronic pain tend to have symptoms such as anxiety, depression, and trouble falling asleep, for months or (in more severe cases) years after the initial injury. Treatments for chronic pain include physical exercise, biofeedback, acupuncture, physical therapy, cognitive behavioral therapy, several types of medications (like specific analgesics and narcotics), and more. Currently, acute and chronic pain is a topic in the medical field that is being closely studied due to its high prevalence in many locations around the world. 

Moving on, pain is subjective, so a noxious physical stimulus may be agonizing to one individual, but that same stimulus may have little effect on another person. This subjectiveness holds true for all types of sensory modalities. Researchers believe that a complex combination of past experiences, present circumstances, and future implications all affect how an individual uniquely perceives an external stimulus. Understanding this subject is crucial in today’s era as the creation of new medical treatments rely on the pre-existing information on a certain illness. For instance, does the patient reporting a slight pain from the same procedure receive the standard analgesic regimen, or should they be treated with a more conservative treatment? 

Furthermore, gender and ethnicity play major roles in individual differences (subjectiveness) in pain. It is clear that those with the XY genotype have substantially different pain tolerances than those with the XX genotype. One large study (N=617) showed that female subjects are slightly more sensitive than males to acute heat pain by about 8%, but in regards to cold pain tolerance, female patients averaged a 40% smaller duration of time than male subjects. Other than gender, cognitive, and psychological components, researchers also believe that each patient’s genetics are also taken into account with determining their subjective opinions to stimuli. From this, one can see how ethnic differences may have a role in differences in perceiving pain. Modern studies revealed differences among ethnic groups such as African Americans, southern Europeans, northern Europeans, and Jews. One study showed that Asian-Americans are more sensitive to heat pain than African Americans, European Americans, and Hispanic individuals, while another noted how European Americans have higher cold pain tolerance than the other groups. Additionally, these ethnic distinctions were expressed in qualitative ways. For example, Hispanic individuals describe the application of the compound capsaicin to the skin as an itch compared to how Asian and European American groups describe the same sensation as painful. Also in the experiment, African American individuals noted a warmness in the targeted skin. Overall, these interpretations should be further studied as comparing differences in a purely genetic context could establish problems due to the varying sociological factors amongst different locations, manipulations of gender expectations, and the aspect of scaling bias (simple numerical scales, 1-100). 

Many individuals say that pain is universal to all humans, but there are some exceptions that exist. One example is the illness: congenital insensitivity to pain, or CIP. Only affecting a few hundred people in the world, CIP is a disorder that prevents the infected from feeling any type of pain or discomfort, as well as preventing them from sweating or feeling extreme temperatures. At the molecular level, CIPA patients have a mutated NTRK1 gene, the gene that normally encodes neurotrophic tyrosine-kinase receptors. As this gene is mutated in a way that interferes and stops the phosphorylation process, signals of temperature and pain are prevented from being sent to the brain. Peculiarly, CIP patients have sensory perceptions parallel to people without the condition. All in all, this disease is devastating as individuals with CIP do not usually live beyond the age of 25. 

In conclusion, pain is a complicated yet vital phenomenon. Pain grants many positives to humans through its role in human survival and experiences. Several types of pain exist that are crucial to how humans function and interact including fast pain, slow pain, neuropathic pain, psychogenic pain, acute pain, and chronic pain. 

It is important to not let pain take over your mind. Pain is a sign that you are pushing yourself, which is an important aspect of athletics, allowing you to get better. Pain is helpful as it allows you to be aware of an injury or a possible injury as well as when your body is at its limit. Therefore, by understanding the concept of pain, athletes can comprehend what pain is and the differences between pain that will be harmful or pain that will aid their performance.

Works Cited

Coghill, Robert C. “Individual Differences in the Subjective Experience of Pain: New Insights into Mechanisms and Models.” Headache, U.S. National Library of Medicine, Oct. 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC2959190/.  

Cox, David. “The Curse of the People Who Never Feel Pain.” BBC Future, BBC, 27 Apr. 2017, www.bbc.com/future/article/20170426-the-people-who-never-feel-any-pain.  

Daneshjou, Khadije, et al. “Congenital Insensitivity to Pain and Anhydrosis (CIPA) Syndrome; A Report of 4 Cases.” Iranian Journal of Pediatrics, Tehran University of Medical Sciences, Sept. 2012, www.ncbi.nlm.nih.gov/pmc/articles/PMC3564101/

Garland, Eric L. “Pain Processing in the Human Nervous System: a Selective Review of Nociceptive and Biobehavioral Pathways.” Primary Care, U.S. National Library of Medicine, Sept. 2012, www.ncbi.nlm.nih.gov/pmc/articles/PMC3438523/.  

Hancock, S, et al. “Clinical Experience across the Fetal-Fraction Spectrum of a Non-Invasive Prenatal Screening Approach with Low Test-Failure Rate.” Ultrasound in Obstetrics & Gynecology : the Official Journal of the International Society of Ultrasound in Obstetrics and Gynecology, John Wiley & Sons, Ltd, Sept. 2020, www.ncbi.nlm.nih.gov/pmc/articles/PMC7496885/.  

Institute of Medicine (US) Committee on Pain, et al. “The Anatomy and Physiology of Pain.” Pain and Disability: Clinical, Behavioral, and Public Policy Perspectives., U.S. National Library of Medicine, 1 Jan. 1987, www.ncbi.nlm.nih.gov/books/NBK219252/.   

Jones, Michael. “Pain and How You Sense It.” MyDr.com.au, 25 Aug. 2020, www.mydr.com.au/pain/pain-and-how-you-sense-it


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