Why we feel pain differently: understanding pain tolerance and thresholds

Written By: Kara Storey-Hind 

Edited by: Violet So 

This article examines what pain really is and why different individuals experience it in unique ways. It will look further into comparing the biological and psychological reasons behind pain tolerances and thresholds, and discuss ways of improving pain tolerance. Additionally, this article will explore interesting examples of instances where our brain interprets pain in particularly peculiar ways. Moreover, it can be proven that the psychological factors of pain tolerance had a stronger influence on pain compared to the biological factors, and that there are various successful ways to improve pain tolerance. 

What is pain and how do we feel it? 

Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage [1]. The way we feel the sensation of pain is due to the transmission of a pain signal to the brain by nociceptors, which are specialised nerve cells also commonly called pain receptors [2]. After being exposed to potentially harmful stimuli such as temperature, pressure, or chemicals, these cells release neurotransmitters to communicate these signals to other nerve cells throughout the body. These signals travel through the body to reach the thalamus, which is the region of the brain responsible for processing sensory signals and directing them to other parts of the brain [2].

Once the signal is received, the brain coordinates a pain sensation with the help of the spinal cord to adjust the severity and intensity of the sensation in response to the perceived threat or injury. This combination of sensory and emotional processing is why pain is considered as a physical and psychological experience, and why depending on the situation and environment it can feel different to the person experiencing it [1]. 

Pain tolerance vs Pain threshold 

There is often confusion between pain tolerance and pain threshold, but it is important to recognise the differences between them as they are very different things. Pain threshold is the minimum intensity at which a person begins to perceive, or sense a stimulus being painful. It is the point at which a sensation changes from being uncomfortable to actually being experienced as pain. Pain tolerance, on the other hand, is the maximum amount, or level, of pain a person can tolerate or bear before it becomes unbearable. This means that two people might begin to feel pain at the same point, yet their ability to cope with this pain could be very different, leading to the distinction in their individual tolerances.

Why do people feel pain differently? 

There are both biological and psychological reasons why people experience pain differently. Biological factors such as age, genetics, and biological sex affect how pain signals are transmitted and processed in the body [3][4]. For example, the different hormones produced for each biological sex can affect pain sensitivity in individuals [4]. Genetics can also influence the sensitivity of pain receptors, as well as age, which can decrease sensitivity to heat pain and pain applied to the head [3]. The psychological factors which influence pain include trauma, stress, anxiety, and attention. For example, trauma from past experiences can change how the brain processes pain signals, as well as attention, stress, and anxiety being able to increase or decrease pain felt even when the same injury is experienced [4]. 

What are some interesting examples of shifts in pain tolerance or threshold? 

One interesting and strong example of how pain tolerance can be changed is the placebo effect, as it is when an individual’s symptoms improve after a fake or inactive treatment because they believe it is real, triggering genuine physical or mental changes through expectation, conditioning, and brain chemistry, like releasing endorphins [5]. A real life example of the placebo effect is from Henry Beecher’s milestone 1955 paper, The Powerful Placebo. Fifteen placebo-controlled trials were examined, and after analysis it was concluded that the placebo effect could be attributed to 35% of patients [5], highlighting just how strongly the mind can influence the perception of pain. 

Another example is when the body releases adrenaline, and the body’s pain threshold is raised significantly due to the activation of the fight-or-flight response, which puts your body in a state of focus to survive, resulting in a faster heart rate, increased breathing, and tenser muscles [6][7]. These adjustments prepare for high stress situations to maximise survival chances by minimising extra stress from pain and other physical sensations for a few hours. This phenomenon explains why some people don’t immediately notice injuries during emergencies [6]. 

Lastly, Phantom pain is experienced when a person experiences a painful sensation in a limb which they no longer have attached to their body. As phantom limb pain is felt in a limb that no longer exists, it is often considered a psychological type of pain and so the pain threshold might be changed due to abnormal nerve signals and significant changes in the areas of the brain which used to be controlled by the missing limb [8]. Due to this type of pain being so unpredictable and chronic, it could lower pain tolerance. Overall this shows that pain tolerance and threshold can also be changed due to the brain’s interpretations of pain signals.

Can pain tolerance be trained? 

Pain tolerance and threshold can be improved by physical activity, due to the release of endorphins, which are a natural painkiller produced by the body [4]. Physical activity can also reduce nerve sensitivity as repeated and regular triggering of pain receptors can result in them becoming less responsive. This means that the same stimulus may produce less discomfort after regular exercise. A way of improving pain tolerance specifically are breathing techniques, mindfulness exercises, placebo effect, and becoming familiar with specific pain [4]. Pain threshold can also be enhanced by hormonal and neural adaptation through repeated and controlled exposure, the use of painkillers and local anaesthetics, and neuroplasticity [4]. Together, these strategies demonstrate both biological and psychological approaches can be used to safely improve management of pain. 

Do biological or psychological factors have a stronger influence on pain? 

Biological factors have a strong influence on pain as they decide how the pain signals are created and transmitted to the brain and the body. Genetics are one of the biggest reasons as to why biological factors have such a strong influence, as they decide the amount of nociceptors you are born with in your body [4]. Also, the brain and spinal cord coordinate a pain response before a person can be consciously aware, bringing a more direct influence on the pain felt [2]. 

However, on the other hand, the psychological factors influencing pain can be seen to impact pain tolerance more drastically with aspects such as distraction, mental state, trauma, emotions, and stress [4]. Psychological factors affect how pain is received, processed, and responded to. This can often override the biological factors and lead to vast differences in pain due to such reasons. Therefore psychological factors overall have a stronger influence on pain. 

Conclusion 

In summary, pain is an impressively complex sensation influenced by both the body and brain. The differences in pain tolerance and threshold between individuals explain why people respond differently to the same stimulus due to biological and psychological factors such as age, genetics, gender, trauma, mental state, and attention. Examples such as phantom limb pain, the placebo effect, and adrenaline highlight interesting ways in which the brain can alter pain perception. After understanding the different factors affecting the sensation of pain we can understand the safe and effective ways of managing the feeling of pain. Understanding the causes for a higher and lower pain tolerance, and ways to improve it is not only important to research in science, but also for the future of medical treatments for both mental and physical pain. This will work towards ensuring a better quality of life for people with chronic pain or a generally low pain tolerance which affects their everyday life. 

Bibliography:

1. European Pain Federation. What Is Pain? Web page, European Pain Federation, n.d. https://europeanpainfederation.eu/what-is-pain/. 

2. National Vulvodynia Association. How We Feel Pain. Web page, National Vulvodynia Association, n.d. https://www.nva.org/learnpatient/how-we-feel-pain/. 3. Mogil, Jeffrey S. “Pain Genetics: Past, Present and Future.” Nature Reviews Neuroscience 13, no. 12 (2012): 859–872. 

https://www.sciencedirect.com/science/article/abs/pii/S0149763416303517. 4. Tracey, Irene, and Patrick W. Mantyh. “The Cerebral Signature for Pain Perception and Its Modulation.” Neuron 55, no. 3 (2007): 377–391. 

https://pmc.ncbi.nlm.nih.gov/articles/PMC6402571/. 

5. Harvard Health Publishing. The Power of the Placebo Effect. Web article, Harvard Medical School, n.d. 

https://www.health.harvard.edu/newsletter_article/the-power-of-the-placebo-effect. 6. King Law. Understanding the Effects of Adrenaline in Car Vehicle Crashes. Web page, King Law, n.d. 

https://kingatlaw.com/understanding-the-effects-of-adrenaline-in-car-vehicle-crashes/. 7. Cherry, Kendra. The Fight-or-Flight Response. Web article, Verywell Mind, n.d. https://www.verywellmind.com/what-is-the-fight-or-flight-response-2795194. 8. Flor, Herta. “Phantom-Limb Pain: Characteristics, Causes, and Treatment.” The Lancet 350, no. 9088 (1997): 1763–1764. https://pubmed.ncbi.nlm.nih.gov/2450442.

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