Influence Of Resistance-exercise Training On Total Physical Activity In Gulf War Veterans With Chronic Pain

Abstract

Nearly 30% of US military Veterans of the Persian Gulf War are currently suffering from debilitating multisymptom illnesses. A primary complaint among these individuals is chronic widespread musculoskeletal pain (CMP). Previously our lab has observed lower levels of total physical activity (PA) in civilian CMP patients compared to their healthy peers. In general, CMP patients with lower levels of PA are at risk for greater disability. While exercise-training interventions may have demonstrated benefits for fitness and health related outcomes, their influence on total PA, particularly in CMP patients, is an open question. PURPOSE: To quantify the influence of a 16-week resistance exercise training (RET) trial on self-reported and actigraphy measures of total PA in Gulf War Veterans (GV) with CMP. METHODS: Fifty-five GV with CMP were randomly assigned to 16 weeks of RET (n=28) or a wait-list control (n=27). The RET consisted of twice weekly sessions with a personal trainer, initiated at a low intensity (25-35% 1 RM) with progression as tolerated. At baseline, 6 weeks, 11 weeks, and 17 weeks, all participants completed the International Physical Activity Questionnaire (IPAQ) and wore a waist-mounted actigraphy monitor (ACTI) for 7 d during waking hours. Total PA was defined for the IPAQ as the summative total score (MET-min/week) and for the ACTI as total counts per day relative to wear time (counts/d/min). Analyses were limited to GV with valid measures at baseline and at least one additional time point. Data were log transformed and extreme outliers (> 3 SD) were excluded. Separate linear mixed models with group and time point as fixed effects were computed for the IPAQ and ACTI measures, using baseline values as a covariate to control for initial differences. RESULTS: GV assigned to RET completed 88% of training sessions and exhibited strength increases of >20% for 7 of 8 lifts. Estimates for the fixed effects and their interaction were not significant for either measure (IPAQ: FG =0.17, FTP = 0.02, FG×TP = 0.09, p < 0.05; ACTI: FG =0.47, FTP = 0.09, FG×TP = 0.22, p < 0.05). CONCLUSION: Although 16 weeks of RET were well attended and resulted in improvements in fitness for GV with CMP, total PA level, outside of the exercise sessions, did not appear to be impacted. Supported by US Department of Veterans Affairs grant #I01CX000383