Circadian variability of blood pressure in obese children.
OBJECTIVE
The aim of the present study was to evaluate the circadian rhythm of blood pressure pattern in obese children, and to investigate if the lack of normal diurnal rhythm of blood pressure is associated with cardiovascular risk factors.


RESULTS
73 obese children (body weight [mean+/-SD]: 89.0+/-17.8 kg; age [mean+/-SD]: 14.2+/-2.3 years), 42 dippers and 31 non-dippers were investigated. Following ambulatory blood pressure monitoring (ABPM), physical fitness testing was performed on a treadmill. Physical working capacity at 130, -150, -170 beat/min (PWC-130, -150, -170), resting and peak oxygen consumption (VO(2)rest, VO(2)peak) were determined. Forty-two percent of obese children were non-dipper. PWC-130 (74.8+/-48.8 watts; 48.0+/-38.5 watts), PWC-150 (132.9+/-52.1 watts; 104.2+/-49.3 watts), PWC-170 (185.9+/-49.5 watts; 154.9+/-53.4 watts) and VO(2)rest, ([mean+/-SD]: 0.29+/-0.08 L/min; 0.26+/-0.07 L/min), and VO(2) peak (2.77+/-0.61 L/min; 2.44+/-0.62 L/min) were significantly lower in the non-dipper group, as compared to dippers (p<0.05). The prevalence of hypertension, on the basis of ABPM, was significantly higher in the non-dipper group (45.2% vs 83.9%, p<0.001). This is due to increased prevalence of masked hypertension in the non-dipper group (19.0% vs 32.3%, p<0.001).


CONCLUSIONS
The normal circadian variation of the blood pressure is frequently absent in obese children. Most of the non-dipper obese children are hypertensive, and their physical fitness is decreased.
Department of Paediatrics, University of Pécs, József A. u. 7., H-7623 Pécs, Hungary. katalin.torok@aok.pte.hu
Katalin
K
Török
Anita
A
Pálfi
Zoltán
Z
Szelényi
Dénes
D
Molnár
D000293:Adolescent; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology; D005080:Exercise Test; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology*; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D010101:Oxygen Consumption; D010809:Physical Fitness / Q000502:physiology*; D012307:Risk Factors