Evening heart rate measured at home is associated with visceral obesity and abnormal fat distribution in patients with hypertension.

BACKGROUND

Our aim was to examine the association between heart rate (HR) and visceral obesity and abnormal fat distribution in patients undergoing treatment for hypertension. We also ascertained whether such associations differ depending on the time of day when HR is measured and the venue at which the measurement is carried out (office or home).

METHODS

The study enrolled a total of 390 patients (mean age 63.9 years; 45% men) receiving treatment with antihypertensive drugs other than β blockers or nondihydropyridine Ca-channel blockers. Office blood pressure (BP) and HR as well as home BP and HR, both morning and evening, were measured in all these patients for 14 days. The amount of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were determined using abdominal computed tomography (CT).

RESULTS

Evening HR was positively associated with VAT (r = 0.26) and negatively associated with SAT (r = -0.16); as a consequence, evening HR was closely associated with the VAT/SAT ratio (r = 0.30; all P < 0.01). In contrast, neither office nor morning HR was associated with VAT. The significant association between evening HR and VAT remained unchanged even after adjustment for significant covariates including SAT (P = 0.001). A multiple logistic regression analysis revealed that a 1-s.d. increase (10 beats per minute) in evening HR was significantly associated with visceral obesity (defined as VAT ≥100 cm)(2) (odds ratio (95% confidence interval: 1.7 (1.3-2.3)), P < 0.001), and that this association was independent of body mass index (BMI) and abdominal obesity (waist circumference ≥85 cm for men and ≥90 cm for women).

CONCLUSIONS

In these patients receiving treatment for hypertension, high evening HR was associated with visceral obesity, independent of the presence of subcutaneous fat and BMI. This novel finding could explain why cardiovascular risk is higher in individuals with high HR.