Is My Pain Caused by Stress?

In a previous post I mentioned research showing that the prevalence of neck pain was 33.9% in people undergoing serious psychological distress. Is my upper back pain caused by stress at work? Is the nerve pain in my butt caused by relationship problems? Is the lower back pain I felt after moving house caused by the stress of moving furniture or the stress of changing my home environment?

As a physical therapist, I am often asked whether I think someone’s pain is coming from their injury or from other stressors in their life. The truth is that it is always a combination, because pain is a summation of all threatening stimuli.

Pain is a response the body creates to stimuli that it perceives as threatening. Pain is an appetite for protection, and its correlation with physical damage can be amazingly poor as I have written about before.

How can I measure and manage my stress response?

By the stress response, I mean both the psychological stress (feeling stressed) and the physiological response (the body’s unconscious response to stress: activation of the sympathetic nervous system and hypothalamic-pituitary-adrenal axis). In an acutely stressful situation, such as giving an improptu speech to a critical audience, you will experience both the psychological response of feeling overwhelmed and the phsyiological response of shallow breathing and a racing heartbeat. But in situations of chronic stress, the physiological response is often less extreme and may go unnoticed, and thus unmanaged.

Measuring Psychological Stress

You can measure your psychological stress with the Perceived Stress Scale [1]. Of the 331 subjects exposed to the common cold in the laboratory, those who reported higher levels of feeling stressed, overwhelmed, and unable to cope with their challenges were more likely to get sick. [2]. A small study found that people with a combination of chronic knee pain and high perceived stress had shorter telomeres (a marker of cellular aging) than those without chronic pain, or those with pain but with less perceived stress [3].

Measuring Physiological Stress

You can measure your physiologic stress response in a variety of ways including heart rate variability, breathing patterns, and brain waves. Here are three devices I have tested both personally and with patients in the clinic to measure manage the physiologic stress response more effectively.

1. Spire
2. SweetBeat Heart Rate Variability
3. Muse

That which gets measured gets managed. Change starts with finding the truth about where you are right now. Knowing to what extent your body is physiologically stressed gives you something more objective to work on than the nebulous “manage your stress.”

1. Spire

The spire is a small wearable that clips on your waistband and measures your physiological stress response by measuring your breathing rate. When you are tense, your breathing is rapid and irregular, spire senses this and notifies you to breath slowly and regularly which calms you down. This is the best tool I have found for measuring and managing the stress response because it is relatively easy to use, can be used all day, and you get to see the results right away. It will also track your steps and let you know when you have been sitting still too long. You just have to remember to put it on your waistband every morning, and avoid dropping it in the toilet. https://spire.io/

2. SweetBeat Heart Rate Variability

Heart Rate Variability (HRV) is the most accurate measure of the stress response of the autonomic nervous system. Your autonomic nervous system consists of a “fight or flight” component called the sympathetic nervous system and a “rest and digest” component called the parasympathetic nervous system.

When you are rested and recovered, your heart rate varies with breathing because your sympathetic system speeds up your heart rate while you breath in and your parasympathetic slows down your heart rate while you exhale. When you are stressed your sympathetic system takes over and your heart beats like a metronome with little variation.

Using a chest strap heart rate monitor and an app called SweetBeatLife you can see your HRV as well as the activity of your parasympathetic system directly (called the HF band). People with lower HF reported greater pain and lower pain thresholds when touched by a 40F metal rod [4]. Doing 30 minutes daily of slow breathing (4sec inhale, 6sec exhale) for a month was shown to increase heart rate variability. HRV is the most accurate method of determining the combined physiological stress load from life and exercise. If my HRV drops for two days in a row, I take a rest day from training and/or spend more time deep breathing. http://www.sweetwaterhrv.com/SweetBeatLife/SweetBeatLife.shtml

3. Muse

Nerves communicate via electrical activity, in aggregate the sum of your brains’ electrical activity makes waves that can be measured from the surface of your scalp using an electroencephalogram (EEG). Basic EEG technology has been around for a long time, but only now is it available to consumers in a portable easy to use format that connects wirelessly to your device for interpretation.

Brain waves are divided into five categories according to their frequency and association with mental states:

• Fast brain waves such as gamma and beta waves are associated with alertness,
• Medium range alpha waves are associated with calm wakefulness,
• Slower theta waves are associated with deep relaxation, and
• Delta waves are usually only found during sleep.

Muse doesn’t show you your brain types specifically, but does some behind-the-scenes proprietary calculations to tell you whether your mind is calm or active by changing the soundscape. I find this lack of transparency a bit irritating, but IT nevertheless it does the job. If I start doing mental math while wearing muse the graph will show my brain was “active,” if I let my mind wander or focus on my breath it will show my brain was “calm.”

I’ve used Muse after an argument to calm down and I have also used it on clients to make sure my massage wasn’t causing too much stress. If you are into meditation but want to skip the woo-woo, Muse is for you.

Summary

These three devices have helped bring objectivity to the often nebulous world of stress management. The main barriers I find to their use is that people don’t have the discipline to use them regularly, and some people get stressed out more by seeing how stressed out they are. To combat these problems I usually only recommend one at a time;  focus mostly on the behaviors that will help manage stress such as deep breathing, sleep hygeine, and regular exercise; and only measure enough to see how things are going.

I put together this chart to compare these three stress management devices.

1. http://www.mindgarden.com/documents/PerceivedStressScale.pdf
2. 1993 Cohen- Negative Life Events, Perceived Stress, Negative Affect and Susceptibility to the Common Cold.
3. 2012 Sibille- Chronic pain, perceived stress, and cellular aging: an exploratory study. 
4. 2008 Appelhans- HRV and pain sensitivity
5. 2012 Tharion- Influence of deep breathing exercise on spontaneous respiratory rate and heart rate variability- a randomized controlled trial in healthy subjects