O'Brien Eoin; Murphy, Joan; Tyndall, Anne; Atkins, Neil; Mee, Fáinsia; McCarthy, Gerry; Staessen, Jan; Cox, John; O'Malley, KevinJournal of Hypertension: April 1991 Original papers: PDF Only Buy Abstract In order to determine reference values for ambulatory blood pressure, a sample of 815 healthy bank employees (399 men and 416 women), aged 17-79 years, were investigated. Ambulatory blood pressure was recorded over 24 h, taking measurements at 30-min intervals. Blood pressure was also measured by trained observers in the clinic. Ambulatory blood pressure in the 815 subjects averaged 118/72 mmHg over 24 h, 124/78 mmHg during the day (1000-2259 h) and 106/61 mmHg at night (0100-0659 h). Office blood pressure, measured by an observer, was 4/2 mmHg lower (P<0.0001) than daytime ambulatory pressure. The 95th centiles for the daytime ambulatory pressure in men were: 114/88 mmHg for the age group 17-29 years (n=107); 143/91 mmHg from 30-39 years (n=123); 150/98 mmHg from 40-49 years (n=109); and 155/103 mmHg in 50-79 year old men (n=60); for the corresponding age groups in women, the 95th centiles of the daytime pressure were: 131/83 mmHg (n=174); 132/85 mmHg (n=149); 150/94 mmHg (n=55); and 177/97 mmHg (n=38). © Lippincott-Raven Publishers.