Ps 02-59 Non-dipping-type Blood Pressure Variations In Young Kazakhs Derived From Increased Sympathetic Activity In The Morning

Objective: Many cases of non-dipping-type blood pressure variations and hypertension have been documented amongst elderly and middle-aged Kazakhs. The purpose of this study was to discover whether there are also large numbers of non-dippers among young Kazakhs and to compare the blood pressure variations seen in these individuals with those observed in age-matched dipping-type Kazakhs. Design and Method: We performed ambulatory blood pressure monitoring and defined non-dippers as individuals that exhibited a nighttime systolic blood pressure (SBP) reduction of Results: Dippers and non-dippers accounted for 73% and 27% of the subjects, respectively. The physiological characteristics of the dippers and non-dippers did not differ, nor did their 24-hr SBP values. However, daytime SBP was lower and nighttime SBP was higher in the non-dippers than the dippers (non-dippers vs. dippers: daytime SBP: 117 ± 5 vs. 123 ± 10 mmHg, P  =  0.022; nighttime SBP: 109 ± 7 vs. 97 ± 7 mmHg, P  =  0.005). MEM analysis of the non-dippers detected SBP variations with a 24-hr frequency periodicity, a very weak power spectral density (PSD), and an ultradian periodicity. The HRV analysis revealed that the low frequency/high frequency ratio was lower in the non-dippers than in the dippers during the morning. Conclusions: Young non-dipping Kazakhs exhibited SBP variations with a 24-hr frequency periodicity, a very weak PSD, and an ultradian periodicity. Furthermore, the non-dippers displayed less sympathetic nerve activity during the morning than the dippers.