서아름,강성구, 신진희, 송상욱

가톨릭대학교 의과대학 가정의학교실

Background : The aim of this study was to investigate the relationship between sleep quality measured by the Pittsburgh Sleep Quality Index (PSQI) and daytime autonomic nervous function reflected in heart rate variability. Methods : Study subjects included those visiting a health promotion center at a medical college from February to April 2007. We assessed sleep quality (using the PSQI) and heat rate variability adjusting for age, weight, height, body mass index, alcohol and caffeine consumption, educational level, regularity of exercise, smoking history, and marital status. Healthy subjects, 76 in number, were divided into two groups- good sleepers (≤5, N=44) vs poor sleepers (≥6, N=32) by the PSQI global score. Five-minute electrocardiographic recordings were analyzed in terms of time and frequency domains. Results : There were no significant differences in baseline characteristics between the two groups. In the spectral analysis of heart rate variability, the square root of the mean of the sum of the square of differences between adjacent NN intervals (RMSSD) and the natural logarithm high frequency (ln HF) were significantly lower in poor sleepers compared to good sleepers (P=0.017, P=0.002). The results of the stepwise multiple regression analysis assessing the relationship between the PSQI subscales and heart rate variability (HRV) parameters showed a significant increase in the mean heart rate (MHR) and a significant decrease in the standard deviation of normal to normal intervals (SDNN), RMSSD, and ln HF according to the "sleep disturbance" scores. in HF was significantly lower according to the "habitual sleep efficiency" scores. Conclusions : We found a significant relationship between poor sleepers and reduced parasympathetic activity in daytime HRV in middle-aged men; and in particular, "sleep disturbance" and "habitual sleep efficiency" (subscales of the PSQI) were related to this reduction. Clinically, this reduced parasympathetic activity seen with poor quality sleep may explain the increased risk for cardiovascular disease. (
Korean J Health Promot Dis Prev 2009;9(4):289-295) Key words : Sleep quality, heart rate variability, Pittsburgh Sleep Quality Index (PSQI)