Blood pressure circadian rhythm and obesity: Blood pressure variations and obesity

INTRODUCTION: The association between obesity and arterial hypertension has been established in a great number of studies. Our objective was to investigate whether circadian rhythm of blood pressure is disturbed among obese people. MATERIAL AND METHODS: In this cros-sectional, randomized study, Schiller BR-102 device was used for ambulatory blood pressure monitoring. One hundred and twenty outpatients were divided into three randomized groups: obese body mass index 30 kg/m2 (52 patients), overweight (28 patients), with body mass index 25.0-29.9 kg/m2 and normal weight (control group) (48 patients), with body mass index 18.5-24.9 kg/m2. In all patients we investigated the following blood pressure parameters: average blood pressure (total, day-time and night-time), maximal blood pressure and dipping or non-dipping blood pressure pattern during night (for systolic and diastolic blood pressure, respectively). RESULTS: In body mass index beyond 30 kg/m2 only systolic blood pressure parameters were significantly higher--average blood pressure--during daytime (P = 0.034) and during night (P = 0.014); maximal blood pressure (P = 0.001). In body mass index beyond 30 kg/m2, absence of normal blood pressure during night was significantly more often registered (P = 0.007). DISCUSSION AND CONCLUSION: The non-dipping blood pressure pattern and increase of systolic blood pressure only reveal hyperactivation of sympathetic nervous system as a leading patophysiological mechanism causing arterial hypertension in obese patients.