Sixteen Weeks of Resistance Training Increases Heart Rate Variability in Women with Fibromyalgia

Abstract

Fibromyalgia (FM) is characterized by low muscular strength, generalized pain and autonomic dysfunction. Heart rate (HR) variability (HRV) is reduced in individuals with FM increasing their risk for cardiovascular diseases. PURPOSE: To test the hypothesis that resistance exercise training (RET) will improve HRV, baroreflex sensitivity (BRS) and pain perception in women with FM. MetHoDs: Women with FM (n=10) and healthy controls (n=9), aged 27-60 years, were compared at baseline. Only women with FM performed 1 set of 8-12 repetitions on 9 resistance exercises, twice a week for 16 weeks. Pre- and post-training measurements included HRV and spontaneous baroreflex sensitivity (BRS, alpha index) from continuous electrocardiogram and blood pressure (BP) recorded with finger plethysmography during 5 min in the supine position. RESULTS: RR interval, total power, log transformed (Ln) squared root of the standard deviation of RR interval (RMSSD), low-frequency power, and BRS were lower (P<0.05), and HR and pulse pressure were higher (P<0.05) in women with FM than in healthy controls. Total power HRV increased from pre- (869±274 ms2) to post-training (1256±360 ms2, P<0.05) and RMSSD increased from pre- (3.04±0.25 Ln ms) to post-training (3.21±0.25 Ln ms, P<0.05) in women with FM. Upper and lower body muscle strength increased by 63 and 49% (P<0.001), and pain perception decreased by 39% in women with FM. There were no significant changes in BRS, high-frequency power HRV, HR and BP after RET. CONCLUSIONS: Our data show that RET improves total power HRV, cardiac parasympathetic tone, muscle strength and pain perception in women with FM who had autonomic dysfunction before the exercise program.