Vagal modulation and symptomatology following a 6-month aerobic exercise program for women with fibromyalgia

Objectives - To examine the effects of a supervised aerobic exercise programme on heart rate variability (HRV) parameters and symptom severity in women with fibromyalgia (FM). Methods - Thirty-two women with FM were randomly allocated to one of two groups: aerobic exercise (AE) or usual care control for 24 weeks. Women allocated to AE performed two aerobic exercise sessions per week of 45-60 min duration including 15-20 min of steady-state aerobic exercise at 60-65% of predicted maximum heart rate (HRmax) and 15 min of interval training at 75-80% HRmax (six repetitions of 1.5 min, with 1 min interpolated rest intervals). Cardiac autonomic modulation was assessed using power spectral analysis of HRV. Symptom severity was assessed by a 10 cm visual analogue scale (VAS) for pain, sleep disturbances, stiffness, anxiety and depression. Results - After 24 weeks, the women in the exercise group showed an increase (4.8±0.2 to 5.2±0.2) in total power (LnTP, p<0.001), low frequency power (LnLF, p<0.01), high frequency power (LnHF, p<0.001), and the root-mean-square of successive R-R intervals (rMSSD, p<0.001). In addition, significant group-by-time interaction effects were observed for LnHF (p=0.036) and LnLF/HF (p=0.014). Improvements in anxiety and depression were also observed in AE versus control patients. Conclusions - These results show that a programme of aerobic exercise training induced changes in cardiac autonomic nervous system modulation in FM and that these changes in HRV parameters were accompanied by changes in anxiety and depression.