High or low intensity aerobic fitness training in fibromyalgia: does it matter?

To determine the efficacy of training in fibromyalgia (FM), we compared the effects of high intensity fitness training (HIF) and low intensity fitness training (LIF).

Thirty-seven female patients with FM were randomly allocated to either a HIF group (n = 19) or a LIF group (n = 18). Four patients (1 HIF group, 3 LIF group) refused to participate after randomization but before the start of the intervention. They were excluded from the analysis. Assessments were performed at baseline and after 20 weeks of HIF or LIF. The primary outcome was patient's global assessment [on 100 mm visual analog scale (VAS)]. Secondary endpoints were pain, number of tender points, total myalgic score, physical fitness, health status, and psychological distress.

One patient in the HIF group (n = 18) and 2 in the LIF group (n = 15) stopped training sessions during the course of the study. Nine of 18 patients in the HIF group compared to 8 of 15 patients in the LIF group achieved a participation rate of 67% or more. Most important reasons for nonadherence were postexercise pain and fatigue, time consumption, and stress. The VAS for global well being improved slightly from 64 to 56 mm in the HIF group, and did not change in the LIF group (58 to 61 mm) (p = 0.07). The Wmax (physical fitness) changed modestly from 110 to 123 watt in the HIF group, and from 97 to 103 watt in the LIF group (p = 0.3). VAS for pain increased from 53 to 64 mm in the HIF group and from 52 to 54 mm in the LIF group. The large standard deviations around mean change in global assessments, number of tender points, total myalgic score, and psychological distress (by SCL-90) severely influenced the power to detect within- and between-group differences. Analysis limited to those patients who accomplished a high attendance rate (> 67%) showed similar results.

High intensity physical fitness training compared to low intensity physical fitness training leads to only modest improvements in physical fitness and general well being in patients with FM, and does not positively affect psychological status and general health.