Effects of Balneotherapy on Circadian Rhythm of Plasma Aldosterone in Patients with Rheumatoid Arthritis

Abstract

It was said that balneotherapy caused an elevation of peak values of plasma cortisol (PC) at 0400 in the patients with rheumatoid arthritis (RA), but there has been no study on plasma aldosterone (PA).
From five patients, 35-77 years old, with mild or inactive RA blood was withdrawn in supine position every four hours one day from 1200 to 1200. After regular bathing (20min. in 39°C hot spring water twice a day) during two weeks a second circadian rhythm study was performed under the same way.
Cosinor method was used as a rhythm analysis.
Normal circadian rhythmicity of PA and PC was preserved in all patients both before and after balneotherapy.
Elevation of peak PC value after balneotherapy was found in all patients but PA was in four only. As for increase of amplitude (obtained from single cosinor method) it was the same as above.
Acrophase of PA circadian rhythm was shifted to earlier in the day in three patients and that of PC was shifted in four patients.
According to group cosinor method, PA amplitude was altered from 29 to 33pg/ml and PC amplitude was altered from 4.5 to 6.5μg/dl. Acrophase of PA was also changed from -97 to -86 deg., PC was from -96 to -82 deg. after balneotherapy respectively.
Conclusion: PA amplitude of circadian rhythm was less affected by two weeks balneotherapy than PC amplitude although a small change may be related to an improvement of autonomic nervous function in chronic disease as RA.