The Japanese Society of Hypertension recommends that evening home blood pressure (HBP) should be measured just before bedtime. However, this timing might be affected by taking a warm or hot bath and/or alcohol intake. The objective was to evaluate the differences in HBP readings taken between before dinner and those taken at bedtime.Design and Method:
Forty-eight patients (mean age 76.4 ± 7.8 yrs; 20 males, 28 females) measured evening HBP twice each day (before dinner and just before bedtime) for 14 days, and they recorded the times at which they took a bath and went to bed, plus information about daily alcohol consumption, if any. We defined the before-dinner (D) minus the at-bedtime (B) systolic HBP difference as the D-B difference.Results:
The number of HBP measurements before dinner and at bedtime was 1,286 and 1,272, respectively. The mean D-B difference was 8.7 mmHg (129.2 vs. 120.5 mmHg). When we divided the patients into four groups according to the time interval from their bath to when they went to bed (≤60 min [n = 267], 61–120 min [n = 276], 121–180 min [n = 140], and ≥181 min [n = 128]) and compared the systolic HBP values between before dinner and at bedtime, the four groups’ D-B differences were 12.8 mmHg (125.0 vs. 112.2 mmHg, p < 0.001), 8.7 mmHg (125.9 vs. 117.2 mmHg, p < 0.001), 2.5 mmHg (129.0 vs. 126.5 mmHg, p = 0.065), and 2.1 mmHg (128.6 vs. 126.5 mmHg, p = 0.133), respectively. The D-B difference with alcohol intake (n = 173) was significantly larger than that without that (n = 836) (10.8 vs. 6.9 mmHg, p = 0.007). The group with both time after bathing ≤120 min and alcohol consumption had significantly larger D-B differences than the other groups (Fig.).Conclusions:
HBP readings taken just before bedtime were lower than those taken before dinner. Physicians should take into account the influence of a bath and alcohol intake in evening HBP measurements.