Investigators from the Research Centre in Physical Activity, Health & Leisure in Porto, Portugal conducted a study to analyze the association between blood pressure and (1) body mass index (BMI), (2) degree of physical activity and (3) cardio-respiratory fitness (CRF) in young people.

The study included 66 boys and 97 girls (average age around 14). Measures were taken of blood pressure and cardio-respiratory fitness during the school day, and accelerometers were used to determine degree of physical activity, both during and away from school.

Higher body mass index was associated with higher systolic (the top number) and diastolic (bottom number) blood pressure (p<or=0.05)  Additionally, systolic, but not diastolic BP, was inversely associated (p<or=0.05) with moderate physical activity and positively correlated with sedentary activities.   

The study concludes that BMI and time spent in sedentary activities were associated with higher systolic blood pressure in younger teens.  And that time spent in moderate physical activity was positively associated with lower systolic blood pressure in this age group.  Body mass index was the single predictor of diastolic blood pressure.

Citation:  Gaya AR, Alves A, Aires L, Martins CL, Ribeiro JC, Mota J.  Association between time spent in sedentary, moderate to vigorous physical activity, body mass index, cardiorespiratory fitness and blood pressureAnnals of Human Biology. 2009 Jul-Aug; 36 (4): pages 379-87. Epub 2009 May 11. [email protected]