Dynamic training and circulating neuropeptides in patients with rheumatoid arthritis: a comparative study with healthy subjects

Abstract

This study aimed at evaluating the effects of a dynamic physical training programme on circulating levels of corticotropin-releasing hormone (CRH), beta-lipotropin (beta-LPH), and beta-endorphin (beta-EP) after high-intensity training for 6 weeks (60 min twice a week) and after low-intensity training (home-training) for another 6 months in patients with rheumatoid arthritis (RA) and in healthy subjects. Additionally, differences in neuropeptide levels between the two groups were studied. A total of 30 patients with RA were randomly allocated to the study, 15 in the training group (TG) and 15 in the control group (CG). In addition, 20 healthy subjects (10 in TG; 10 in CG) participated. In addition to the biochemical analyses, the following variables were assessed for the RA group: pain and disability (Stanford health assessment questionnaire), joint tenderness (Ritchie articular index), disease activity, muscle function, aerobic capacity, sociodemographic data and attitudes. The results obtained at the start revealed significant differences (p < 0.05) between RA patients and healthy subjects concerning CRH levels, RA patients showing the lower levels (RA-group Md = 24 pmol/L, healthy group Md = 29 pmol/L). No significant differences concerning beta-LPH and beta-EP were found here. After the high-intensity training period, a significant increase of the CRH levels were found for the RA-TG (pretest Md = 24 pmol/L, after 6 weeks Md = 27 pmol/L, p < 0.05). No such results were found for the healthy-TG or the control groups. Concerning beta-EP, significant differences between the RA-TG and healthy-TG were found after the training. RA patients generally showing higher levels as compared with the healthy (RA-group Md = 42 pmol/L, healthy group Md = 36 pmol/L, p < 0.05). The same pattern was found for the beta-LPH levels. In conclusion, the effects of physical training on circulating neuropeptides remain still incompletely examined, and there is no definite answer to the question whether increased beta-EP levels are good or bad.