Why is back pain or a knee injury annoying to one person and sheer agony to another? Turns out, an individual’s tolerance to pain is as unique as the person. It is shaped by some surprising biological factors, as well as some psychological factors that we can actually try to control.
Feeling pain is an important experience. It can alert you to a potential illness or injury that needs to be addressed. When you feel pain, nearby nerves send signals to your brain through your spinal cord. Your brain interprets this signal as a sign of pain, which can set off protective reflexes. For example, when you touch something hot, your brain receives signals indicating pain. This in turn can make you quickly pull your hand away without even thinking.
Many things can influence the complex system of communication between your brain and body. There are two steps to feeling pain. First is the biological step, for example, the pricking of skin or a headache coming on. These sensations signal the brain that the body is experiencing trouble. The second step is the brains perception of the pain and our reaction to it. Do we shrug off these sensations and continue our activities or do we stop everything and focus on what hurts?
“Pain is both a biochemical and neurological transmission of an unpleasant sensation and an emotional experience,” Doris Cope, MD, an anesthesiologist who leads the Pain Medicine Program at the University of Pittsburgh Medical Center. “Chronic pain actually changes the way the spinal cord, nerves, and brain process unpleasant stimuli causing hypersensitization, but the brain and emotions can moderate or intensify the pain.” Past experiences and trauma, Cope says, influence a person’s sensitivity to pain.
Pain produces a significant emotional, physical, and economical toll in the U.S. Chronic pain results in health care expenses, lost income and lost productivity estimated to cost $100 billion every year.
Everyone struggles with pain at some point, but how you tolerate pain can be up to you.
What is pain tolerance?
Pain comes in many forms, whether it’s from a burn, joint ache, or throbbing headache. Your pain tolerance refers to the maximum amount of pain you can handle. This is different from your pain threshold.
What is your pain threshold?
Your pain threshold is the minimum point at which something, such as pressure or heat, causes you pain. For example, someone with a lower pain threshold might start feeling pain when only minimal pressure is applied to part of their body.
Pain tolerance and threshold varies from person to person. They both depend on complex interactions between your nerves and brain.
What drives your pain tolerance?
Pain tolerance is influenced by people’s emotions, bodies, and lifestyles. Here are several factors that Grabois says can affect pain tolerance:
• Depression and anxiety can make a person more sensitive to pain.
• Athletes can withstand more pain than people who don’t exercise.
• People who smoke or are obese report more pain.
Biological factors – including genetics, injuries such as spinal cord damage, and chronic diseases such as diabetes that cause nerve damage- also shape how we interpret pain.
1. Your dominant side
Some surprising biological factors may also play a role in pain tolerance. For example, recent research shows that one side of your body may experience pain differently than the other side.
A study published in the December 2009 issue of Neuroscience Letters showed that right-handed study participants could tolerate more pain in their right hands than in their left hands. A dominant hand – your right hand, if you’re right-handed, for example –may interpret pain more quickly and accurately than the non-dominant hand, which may explain why the dominant side can endure longer. Hand dominance may also be linked to the side of your brain that interprets the pain, the researchers note.
2. Hair color
Another surprising factor is that hair color may reflect pain tolerance. In 2009, researchers reported in the Journal of the American Dental Association showed that redheads were more sensitive to pain and may need more anesthesia for dental procedures.
Why redheads in particular? Redheads, the researchers say, tend to have a mutation in a gene called melanocortin-1 receptor (MC1R), which is what helps make their hair red. MC1R belongs to a group of receptors that include pain receptors in the brain. The researchers suggest that a mutation in this particular gene appears to influence sensitivity to pain.
3. Pain receptors
“We have different receptors for pain in our body, and those receptors respond differently, whether you’re taking aspirin or acetaminophen i.e. Tylenol,” Stelian Serban, MD, director of acute and chronic inpatient pain service and an assistant professor of anesthesiology at The Mount Sinai Medical Center in New York, tells WebMD.
Genes play an important part in determining one’s sensitivity to pain. Thank your parents if you have the gene that blocks BH4, a chemical in your body that increases pain sensitivity. If your body naturally blocks BH4, you are less sensitive to pain, and have a reduced risk for chronic pain, according to the Harvard University Gazette.
A study finds women experience more pain after surgery than men. And, a 2002 study by the Center for Neurosensory Disorders at the University of North Carolina found females have a lower pain threshold than males. The reason is the female body releases fewer natural painkillers (beta endorphins) than the male body. Although I’d really like to test this hypothesis by having men go through childbirth and see how well the human population survives.
6. Your brain
Your brain’s wiring could be an indicator for your threshold of pain. One study reveals a correlation between a person’s sensitivity to pain and the thickness of the cortex in the brain. Other studies show that less gray matter in the brain can also be a link to higher pain sensitivity.
We can’t change our genetic receptors, and not even changing your hair color or which hand you write with can rewire your sensitivity to pain. However, there are coping mechanisms that can influence the brain’s perceptions of pain.Researchers have focused on trying to alter the psychological interpretations of pain by retraining the mind. “You can change the perception [of pain] on the brain,” Grabois says. “You haven’t changed the perception on the nerves.” The experience of pain is complex. While you can’t always change the source of your pain, there are ways you can alter your perception of pain. Just make sure you see a doctor if you have pain that’s persists, gets worse or interferes with your day-to-day life.
Next week I’ll talk about ways to decrease our perception of pain, including our pain tolerance and how to reach a point where it can be lived with.