(184) Pain sensitivity is associated with vigorous physical activity and high cardiorespiratory fitness

Abstract

Current activity recommendations are based primarily on epidemiologic evidence of an inverse relationship between volume of physical activity (PA) and overall risk of chronic disease, disability, and ultimately, mortality. Although exercise is often recommended to prevent and treat chronic pain conditions, whether or not greater physical activity reduces pain sensitivity remains unclear. Thus, the primary goal of this study was to compare pain sensitivity in highly active and sedentary adults. We assessed pain sensitivity, 7-day PA, and cardiorespiratory fitness in 59 pain-free adults (29F, 30M; 18-45 yrs). Pain sensitivity was assessed using pressure pain thresholds (PPTs) of the middle deltoid, pressure temporal summation (TS) of the dorsal forearm, and conditioned pain modulation (CPM) using middle deltoid PPTs before and after contralateral cold water hand immersion. PA was assessed via self-report (International Physical Activity Questionnaire) and wrist-worn accelerometry (Actigraph; ± 6g triaxial). Cardiorespiratory fitness was estimated using a submaximal step test to classify participants as having low, average, or high fitness. PPTs were highest (lowest sensitivity) in the high fitness group (p ≤ 0.01) while no differences were noted between fitness groups for TS (p = 0.21) or CPM (p = 0.97). Pressure pain sensitivity decreased with increasing levels of self-reported and measured (accelerometry) vigorous PA (rs = 0.44, p ≤ 0.01). Less TS was observed with increasing vigorous self-reported PA only (rs = -0.29, p < 0.05), while CPM was not associated with activity level. These results suggest that PPTs are more sensitive to physical activity and fitness differences than pressure TS or CPM in a young, healthy cohort. Supported in part by University of Iowa Physical Therapy & Rehabilitation Science Department, University of Iowa, Carver College of Medicine NIH Training Grant, and NIH CTSA U54TR001013.