Are Physical Activity And Sedentary Behavior Predictive Of Pain In Veterans With Chronic Widespread Pain?

Chronic widespread pain (CWP) is a primary symptom affecting Gulf War Veterans (GWV). GWV with CWP have heightened sensitivity to noxious stimuli and are less physically active than their pain-free GWV counterparts. Pain sensitivity has been negatively associated with physical activity (PA) and positively associated with sedentary behavior (SB) in fibromyalgia, a disorder characterized by widespread pain, but this relationship in GWV is less well studied. PURPOSE: To examine the relationship between PA, SB, pain symptoms, and pain sensitivity in GWV with CWP. METHODS: Activity levels, bodily pain scores, and experimental heat pain ratings were collected from 136 GWV with CWP (age = 50 ± 6 yrs; BMI = 30 ± 5 kg/m2; female = 13%) across three separate studies. PA and SB were measured via hip-worn accelerometers (n = 113), bodily pain was measured using the Veterans RAND 36 Item Health Survey (VR36; n = 111), and pain intensity and unpleasantness ratings were collected during exposure to 45 °C, 47 °C, and 48.9 °C thermal stimuli (n = 74). Separate linear mixed effects models determined whether PA (i.e., total counts/min/day, moderate-vigorous min/day, and percent of wear time spent in light activity) or SB (i.e., percent of wear time spent sedentary) predicted bodily pain and pain sensitivity (i.e., intensity and unpleasantness). Model covariates included study assignment (categorical random factor), age, BMI, fibromyalgia status, and the VR36 mental component score. RESULTS: Neither PA nor SB were significantly associated with bodily pain or pain sensitivity ratings in any of the models. CONCLUSIONS: Contrary to CWP research in civilian populations, current levels of PA and SB were not predictive of either self-reported chronic pain symptoms or pain sensitivity to noxious thermal stimuli in GWV with CWP. Supported by Dept. of Veterans Affairs grants: I01 CX001329, I01 CX000383, 561-00436