Heart rate and blood pressure response to exercise and recovery in subclinical hypothyroid patients

BACKGROUND: Exercise response of asymptomatic subclinical hypothyroid patients may aid in early diagnosis of cardiovascular morbidity. AIM: To study and compare the heart rate and blood pressure changes during exercise and recovery in subclinical hypothyroid patients and euthyroid controls. MATERIALS AND METHODS: For the study, 30 each cases (mean age of 40 ± 7 years) of subclinical hypothyroidism and healthy controls underwent exercise as per Bruce protocol. Heart rate (HR) and blood pressure (BP) changes were compared every minute (min) till 3 min of stage II exercise, continued till maximum heart rate and thereafter on recovery, for 5 min after stoppage of exercise. RESULTS: Both groups had normal HR and BP at rest, heart rate and BP increased with exercise and remained high even after 5 min of recovery from exercise. The increase in systolic blood pressure (SBP) with exercise was less in patients at the stage of exercise where maximum HR was achieved and up to 1 min of recovery. SBP at 5 min of recovery was higher in patients (P = 0.018). Diastolic blood pressure (DBP) increased with exercise and changes were similar in both groups during exercise and recovery. HR was higher in patients at 1 min of exercise. Changes in HR from 1 min of recovery to 2-5 min of recovery were significant in both groups. CONCLUSION: The present pilot study highlights that many parameters of HR and SBP during exercise and recovery in asymptomatic subclinical hypothyroid patients may differ from euthyroid, controls.