title: The association between seven-day objectively measured habitual physical activity and 24 h ambulatory blood pressure: the SABPA study.
abstract: Few studies have examined objective physical activity in relation to 24 h ambulatory blood pressure (BP). We aimed to assess the association of 7-day objectively measured habitual physical activity with ambulatory BP in a sample of African and Caucasian school teachers (n=216, age 49.7 years) from the sympathetic activity and blood pressure in Africans prospective cohort study. Hypertension (ambulatory systolic BP⩾130 and/or diastolic BP⩾80 mm Hg) was prevalent in 53.2% of the sample, particularly in black Africans. The hypertensive group spent significantly more awake time in sedentary activity (51.5% vs 40.8% of waking hours, P=0.001), as well as doing less light- (34.1% vs 38.9%, P=0.043) and moderate-intensity (14.0% vs 19.7%, P=0.032) activities compared with normotensives, respectively. In covariate adjusted models, light-intensity activity time was associated with lower 24 h and daytime ambulatory systolic BP (β=-0.15, 95% confidence interval (CI): -0.26, -0.05, P=0.004; β=-0.14, CI: -0.24, -0.03, P=0.011) and diastolic BP (β=-0.14, CI: -0.25, -0.03, P=0.015; β=-0.13, CI: -0.24, -0.01, P=0.030), as well as resting systolic BP (β=-0.13, CI: -0.24, -0.01, P=0.028). Sedentary time was associated only with 24 h systolic BP (β=0.12; CI: 0.01, 0.22), which was largely driven by night-time recordings. Participants in the upper sedentary tertile were more likely to be 'non-dippers' (odds ratio=2.11, 95% CI: 0.99, 4.46, P=0.052) compared with the lowest sedentary tertile. There were no associations between moderate to vigorous activity and BP. In conclusion, objectively assessed daily light physical activity was associated with ambulatory BP in a mixed ethnic sample.
authors.affiliation: Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North-West University, Potchefstroom, South Africa.|School Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
authors.forename: M
authors.initials: M
authors.lastname: Hamer
authors.affiliation: Physical Activity, Sport and Recreation Research Focus Group, North-West University, Potchefstroom, South Africa.
authors.forename: E J
authors.initials: EJ
authors.lastname: Bruwer
authors.affiliation: Physical Activity, Sport and Recreation Research Focus Group, North-West University, Potchefstroom, South Africa.
authors.forename: J H
authors.initials: JH
authors.lastname: de Ridder
authors.affiliation: Physical Activity, Sport and Recreation Research Focus Group, North-West University, Potchefstroom, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Swanepoel
authors.affiliation: Non-Communicable Diseases Research Unit, South African Medical Research Council, Cape Town, South Africa.|Department of Medicine, University of Cape Town, Cape Town, South Africa.
authors.forename: A P
authors.initials: AP
authors.lastname: Kengne
authors.affiliation: Faculty of Health Sciences Statistical Group, North-West University, Potchefstroom, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Cockeran
authors.affiliation: Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North-West University, Potchefstroom, South Africa.
authors.forename: L
authors.identifier: 0000-0003-3187-2410
authors.initials: L
authors.lastname: Malan
mesh_terms: D000328:Adult; D044383:Black People; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D002940:Circadian Rhythm; D015444:Exercise; D005260:Female; D006184:Habits; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011237:Predictive Value of Tests; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D000070777:School Teachers; D057185:Sedentary Behavior; D013019:South Africa / Q000453:epidemiology; D013997:Time Factors; D044465:White People