Heart rate recovery and chronotropic incompetence in patients with prehypertension.

The study was aimed to evaluate the function of the autonomic nervous system by heart rate recovery (HRR) and chronotropic incompetence (CIc) in patients with prehypertension.Subjects were classified into three groups by JCN 7 REPORT: 1) hypertension in the case of systolic blood pressure of ≥140 mmHg or diastolic blood pressure of ≥90 mmHg; 2) prehypertension in the case of systolic blood pressure of 120~139 mmHg or diastolic blood pressure of 80~89 mmHg; and 3) normal in the case of systolic blood pressure of <120 mmHg and diastolic blood pressure of <80 mmHg. HRR and CIc in 147 subjects with prehypertension, 147 subjects with hypertension and 211 subjects with normal blood pressure were measured.HRR was significantly lower in subjects with prehypertension than in subjects with normal blood pressure (37.27±11.93 vs. 34.17±11.03, P<0.05), but there was no significant difference between subjects with hypertension and subjects with prehypertension. With regard to the CIc, subjects with hypertension showed significantly higher frequency than both subjects with normal blood pressure and with prehypertension (P<0.05). The results of multiple regression analysis showed that the HRR was significantly influenced by such factors as age (P<0.001), waist size (P<0.001), HDL cholesterol (P<0.001), heart rate at rest (P<0.001), maximum heart rate (P=0.049) and maximum systolic blood pressure (P=0.007).Subjects with prehypertension showed a lower HRR compared with those with normal blood pressure, which proves that the dysfunction of the autonomic nervous system also appears in patients with prehypertension, the previous stage of hypertension.