Autonomic Reactivity With Altered Thyroid Status

ABSTRACT

The study was carried out to test the effect of altered thyroid status on the autonomic reactivity in 60 subjects (age group 20-50 years). The para meters recorded and the tests used were pulse rate, blood pressure, orthostasis, cold pressor test, mental arithmetic and QTc interval for assessment of sympathetic activity and valsalva ratio, heart rate response, expiratory-inspiratory ratio (E.I. ratio), heart rate variability, standing-lying ratio (S.L. ratio) and 30 15 ratio for assessment of parasympathetic activity. Our findings show that the changes in thyroid hormone levels - in both hypothyroids and hyperthyroids are associated with altered sympathetic reactivity, with no significant difference in the parasympathetic activity - in either hypothyroids or hyperthyroids- as compared to euthyroid controls.