Effects of alcohol restriction on ambulatory blood pressure, heart rate, and heart rate variability in Japanese men

We investigated the effects of alcohol restriction on ambulatory blood pressure (BP), heart rate, and heart rate variability in 33 Japanese male volunteers (37 ± 1 years, mean ± SE), who were all habitual drinkers. Subjects were told either to keep their usual drinking habits for 3 weeks (usual alcohol period), or to reduce alcohol intake by at least half of their usual drinking amount (reduced alcohol period). The ambulatory BP, heart rate, and electrocardiographic R-R intervals were measured during a 24-h period with a portable recorder on the last day of each period. A power spectral analysis of R-R intervals was performed to obtain the low-frequency (LF) and high-frequency (HF) components. The percentage of differences between adjacent normal R-R intervals >50 msec (pNN50) was also calculated. The amount of ethanol intake was significantly reduced from 70 ± 5 mL/day in the usual alcohol period to 19 ± 3 mL/day in the reduced alcohol period (P< .0001). The daytime systolic BP was significantly lower in the reduced alcohol period than in the usual alcohol period by 4 ± 1 mm Hg (P< .05). The daytime and nighttime heart rate was significantly lower in the reduced alcohol period than in the usual alcohol (P< .001 for each). The pNN50 and the HF component were significantly higher in the reduced alcohol period than in the usual alcohol period (P< .0001 for each). The LF/HF ratio was significantly lower in the reduced period than in the usual period (P< .01). These results demonstrate that 3-week alcohol restriction produced reductions in ambulatory systolic BP, heart rate, and the index of sympathovagal balance, and augmentations of parasympathetic indices of heart rate variability in Japanese male drinkers.