Abstract
IntroductionFibromyalgia (FM) is characterized by chronic pain. Impaired growth hormone responses and reduced serum insulin-like growth factor 1 (IGF-1) are common in FM. The aim was to examine changes in serum IGF-1, cerebrospinal fluid (CSF), neuropeptides, and cytokines during aerobic exercise in FM patients.MethodsIn total, 49 patients (median age, 52 years) with FM were included in the study. They were randomized to either the moderate- to high-intensity Nordic Walking (NW) program (n = 26) or the supervised low-intensity walking (LIW) program (n = 23). Patients participated in blood tests before and after 15 weeks of aerobic exercise. Changes in serum levels of free IGF-1, pain rating on a 0- to 100-mm scale, pain threshold, and 6-minute walk test (6MWT) were examined. CSF, neuropeptides, matrix metalloproteinase 3 (MMP-3), and inflammatory cytokines were determined. Nonparametric tests were used for group comparisons and correlation analyses.ResultsSerum free IGF-1 levels did not change during 15 weeks of exercise between the two groups, although the 6MWT significantly improved in the NW group (p = 0.033) when compared with LIW. Pain did not significantly change in any of the groups, but tended to decrease (p = 0.052) over time in the total group. A tendency toward a correlation was noted between baseline IGF-1 and a decrease of pain in response to exercise (r = 0.278; p = 0.059). When adjusted for age, this tendency disappeared. The change in serum free IGF-1 correlated positively with an alteration in CSF substance P (SP) levels (rs = 0.495; p = 0.072), neuropeptide Y (NPY) (rs = 0.802; p = 0.001), and pain threshold (rs = 0.276; p = 0.058). Differing CSF SP levels correlated positively to a change in pain threshold (rs = 0.600; p = 0.023), whereas the shift in CSF MMP-3 inversely correlated with an altered pain threshold (rs = -0.569; p = 0.034).ConclusionsThe baseline level of serum free IGF-1 did not change during high or low intensity of aerobic exercise. Changes in IGF-1 correlated positively with a variation in CSF SP, NPY, and pain threshold. These data indicate a beneficial role of IGF-1 during exercise in FM.Trial registration: ClinicalTrials.gov NCT00643006.
Highlights
Fibromyalgia (FM) is characterized by chronic pain
One third of FM patients are estimated to suffer from growth hormone (GH) deficiency, with impaired growth hormone responses leading to reduced insulin-like growth factor 1 (IGF-1), a critical mediator of growth hormone [5,6,7]
The effects of Nordic walking on body function were reported previously [4], showing that Nordic Walking (NW) resulted in better improvement in the 6-minute walk test (6MWT) and aerobic capacity, when compared with patients in low-intensity walking (LIW)
Summary
Fibromyalgia (FM) is characterized by chronic pain. Impaired growth hormone responses and reduced serum insulin-like growth factor 1 (IGF-1) are common in FM. The aim was to examine changes in serum IGF-1, cerebrospinal fluid (CSF), neuropeptides, and cytokines during aerobic exercise in FM patients. Fibromyalgia (FM) is characterized by chronic pain, tenderness [1], and enhanced central sensitivity [2]. Low-grade inflammation could be Approximately one third of FM patients are estimated to suffer from growth hormone (GH) deficiency, with impaired growth hormone responses leading to reduced insulin-like growth factor 1 (IGF-1), a critical mediator of growth hormone [5,6,7]. The major IGF-binding protein in serum and extracellular fluid is insulin-like growth binding protein 3 (IGFBP3). IGFBP3 did not change significantly in FM patients after 6 months of exercise [10]
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