Light-intensity PA was found to be beneficially associated with obesity , markers of lipid and glucose metabolism , and mortality .
Conclusions Observational evidence that light-intensity PA can confer health benefits is accumulating .
Background The health effects of light-intensity physical activity ( PA ) are not well known today .
Objective We conducted a systematic review to assess the association of accelerometer-measured light-intensity PA with modifiable health outcomes in adults and older adults .
Objectively measured physical activity is associated with parameters of bone in 70-year-old men and women.
As the world 's population ages , the occurrence of osteoporosis-related fractures is projected to increase . Low areal bone mineral density ( aBMD ) , a well-known risk factor for fractures , may be influenced by physical activity ( PA ) . In this cross-sectional study , we aim ed to investigate potential associations between objective measures of PA and bone properties , in a population -based cohort of 1228 70-year-old men and women . We measured volumetric BMD ( vBMD , mg/cm(3 ) ) together with cross-sectional area ( CSA , mm(2 ) ) by peripheral quantitative computed tomography at sites located 4 % and 66 % in the distal-proximal trajectory at the tibia and radius . We also measured aBMD ( g/cm(2 ) ) by dual energy X-ray absorptiometry at the femoral neck , lumbar spine ( L1-L4 ) and radius . Participants wore triaxial accelerometers for 7 consecutive days to obtain objective estimates of PA . The intensity of the objective PA was divided into light ( 100 - 1951 counts/min [ CPM ] ) , moderate ( 1952 - 5724 cpm ) and vigorous ( ≥ 5725 cpm ) . Maximal accelerations for the anterior-posterior ( z ) , medio-lateral ( x ) , and vertical ( y ) axes were also separately assessed . Associations were investigated using bivariate correlations and multiple linear regression , adjusted for height , weight and sex . Vigorous PA showed the strongest association with femoral neck aBMD ( β=0.09 , p<0.001 ) , while both moderate and vigorous PAs were associated with cortical area and trabecular vBMD in the weight-bearing tibia ( all p<0.05 ) . Peak vertical accelerations were associated significantly with cortical area ( β=0.09 , p<0.001 ) and trabecular vBMD ( β=0.09 , p=0.001 ) of the tibia , whereas peak anterior-posterior accelerations showed no correlation with these properties . No positive association was found between objective ly measured PA and bone parameters of the radius . In conclusion , vertical accelerations and moderate to vigorous PA  independently predict bone properties , especially in the weight-bearing tibia , in 70-year-old men and women
Light-intensity PA was found to be beneficially associated with obesity , markers of lipid and glucose metabolism , and mortality .
Conclusions Observational evidence that light-intensity PA can confer health benefits is accumulating .
Background The health effects of light-intensity physical activity ( PA ) are not well known today .
Objective We conducted a systematic review to assess the association of accelerometer-measured light-intensity PA with modifiable health outcomes in adults and older adults .