31P magnetic resonance spectroscopy of skeletal muscle in patients with fibromyalgia.
Jacobsen S., Jensen KE., Thomsen C., Danneskiold-Samsoe B., Henriksen O.
31Phosphorous nuclear magnetic resonance (31P NMR) spectroscopy of painful calf muscle was performed in 12 patients with fibromyalgia (FS) and 7 healthy subjects during rest, aerobic and anaerobic exercising conditions, and postexercise recovery. Ratios of inorganic phosphate and creatinine phosphate (Pi/PCr) and pH were calculated from the collected 31P NMR spectra. Resting values of Pi/PCr were normal in the patients. Patients delivered only 49% of the muscle power of the controls (p = 0.005). Patients and controls had similar rates of Pi/PCr and pH changes during work and recovery. The controls were able to change their Pi/PCr and pH more than the patients, due to the greater workload reached. However, statistical significance was reached only for the anaerobic static exercise (p = 0.003). It was concluded that patients with FS have a reduced voluntary capacity for work, but normal biochemical response to work and recovery.