Repeated ambulatory monitoring reveals a Monday morning surge in blood pressure in a community-dwelling population

Background Although weekly variations with a peak on Monday have been reported in the incidence of cardiovascular events, few studies have investigated weekly variations in blood pressure (BP). Methods One hundred and thirty-five community-dwelling subjects had 24-h ambulatory BP monitoring for 7 days. We calculated the mean awake, asleep, morning (during the first 3 h after awaking) BP, and morning BP surge (mean morning systolic BP minus mean asleep systolic BP) for each day. Results Monday surge in BP was found in the awake and morning BP (awake BP: 128.8 ± 15.4/79.1 ± 9.2 v 131.5 ± 16.3/80.7 ± 10.0 mm Hg, P< 0.01, respectively; morning BP: 127.3 ± 17.8/78.8 ± 11.4 v 132.5 ± 18.2/81.2 ± 10.0 mm Hg, P< 0.01, respectively) but was not found in the asleep BP (112.7 ± 18.3/68.4 ± 10.7 v 113.1 ± 17.6/68.7 ± 10.5 mm Hg, P = NS, respectively). The morning BP surge on Monday was higher than on the other days of the week except for Tuesday (Monday: 19.7 ± 13.3 mm Hg v Friday: 16.4 ± 12.9 mm Hg, P< 0.05; v Saturday: 14.7 ± 13.3 mm Hg, P< 0.01 v Sunday: 13.7 ± 12.0 mm Hg, P< 0.01; v Wednesday: 15.5 ± 14.3 mm Hg, P< 0.01). Conclusion Morning BP surge was the greatest on Monday in a community-dwelling population. This may be in accord with clinical evidence that cardiovascular events more frequently occur in the morning on Monday.