Are you Marinating in Stress?
The chemistry of stress and how it affects your muscles.
By Dr. Elke
Ever wondered why you feel pain when you’re stressed but when you go on vacation, it tends to go away? Or how it hurts way more when you stub your toe when you’re upset versus when you’re in a good mood? It’s really all about the brain and the chemistry our bodies are marinating in.
When we have any chemical, emotional or physical stressors (good or bad) we respond to them. Our brain takes sensory input (our feelings, our stress, our body position, our environment, our pizza etc.) and the hypothalamus (a fun area in our brain that integrates information) instructs certain hormones to set out and patrol our bodies, which tell our bodies how to respond to the input. It’s these changes in internal chemistry that alter our perception of pain*.
If you’ve had a really bad day at work, or someone cut you off while driving, or that house of cards you’ve been making blew over, you can get pretty heated! This increases the sympathetic activity in the body (fight or flight) and in turn causes hormones like adrenaline and cortisol to run through your body. Long-term activation of the sympathetic nervous system triggers an inflammatory response and a substance, aptly named Substance P (think of ‘P’ for pain), increases, and in so doing affects our perception of pain**,***. This chronic activation can also trigger chronic and painful muscle contractions like tension headaches, and ‘work-related’ muscle pain. But when we have less stress and less stress hormones in our bodies the outcome is completely different. That stubbed toe isn’t as bad as last time…
When you decrease the tone of the sympathetic nervous system, you can decrease this muscle tension. The cerebellar vermis (a worm-like area in our cerebellum) has also been shown to play a role in pain perception and muscle tone. One study in particular used Positron Emission Tomography (PET) – a type of imaging that tracks where glucose is taken up in the brain. Glucose is used as energy, so if an area of the brain is taking up glucose, it means it is active. When patients were given a cue that something was about to hurt them, the cerebellar vermis increased its glucose uptake. When patients experienced and responded to pain, the cerebellar vermis increased its glucose uptake again. The authors of the study suggest that the cerebellar vermis can be deactivated with a reduction in sympathetic and muscle tone. This study in particular found that a chiropractic adjustment could reduce sympathetic tone. With this reduced system activation, glucose uptake actually increased in the areas of the brain responsible for relaxation****.
What does it all mean??? It means we have some say in how we take our pain. Our pain depends on how our brain perceives and responds to sensory input. The longer we stay in stress-mode, the more it might hurt. In a world full of fried food, crying babies, bad drivers, falls, poor posture, negative thoughts, and information constantly being thrown at us, we definitely can’t eliminate our stress, but we can get better at adapting to it. Some chiropractic, yoga, gratitude, and good ol’ deep breathing will help you on your way.
*Minardi J. The power of chiropractic [notes from unpublished lecture]. Holiday Inn Mississauga; October 8 2016.
**Mantyh PW. Neurobiology of substance P and the NK1 receptor. Journal of Clinical Psychiatry 2002; 63; 11: 6-10.
***Widmaier EP, Raff H, Strang KT. Vander’s Human Physiology: the mechanisms of body function. 11th ed. McGraw-Hill; 2008. Chapter 7, Sensory Physiology; p. 233.
****Ogura T, Manabu T, Masud M, et al. Cerebral metabolic changes in men after chiropractic spinal manipulation for neck pain. Alternative therapies 2011;17;6: 12-17.