Hypothalamic-pituitary-adrenal hormonal responses to exercise stress test in patients with rheumatoid arthritis compared to healthy controls

Objective. There is controversy about hormonal dysfunction in the hypothalamic-pituitary-adrenal (HPA) axis that is supposed to contribute to the development or persistence of rheumatoid arthritis (RA). We investigated whether there is an altered and blunted response of the HPA axis when stimulated by exercise stress in patients with RA. Methods. Twenty women with RA and 15 matched healthy controls were included in the study. All subjects took an ergospirometric exercise test on the treadmill to determine anaerobic threshold (AT). On another day, blood was collected for basal plasma levels of growth hormone (GH), insulin-like growth factor-I, cortisol, and adrenocorticotrophic hormone (ACTH); and subjects exercised on treadmill at an intensity above their AT. Blood was collected again to measure hormone levels just after the exercise stopped and 60 minutes later. Results. Two subjects left the study, so 19 patients and 14 controls were evaluated. Peak oxygen consumption (VO2), VO2 at AT, exercise test duration, and basal hormone levels were similar in groups. In both groups, GH slightly increased just after the exercise (0 min), and decreased at 60 min compared to baseline, but the change was not different between groups. Cortisol levels decreased significantly at 0 and 60 min in both groups, ACTH levels did not change in time, and there was no difference between groups. Conclusion. There was no perturbation in HPA axis stimulated by exercise stress test in patients with RA and all the variables measured were similar to those of the control group.