Joint associations between objectively measured physical activity volume and intensity with body fatness: the Fenland study.
International Journal of Obesity 2021
PubMed ID : 34593963
PMCID : PMC8748201
Physical activity energy expenditure (PAEE) represents the total volume of all physical activity. This can be accumulated as different underlying intensity profiles. Although volume and intensity have been studied in isolation, less is known about their joint association with health. We examined this association with body fatness in a population-based sample of middle-aged British adults.
In total, 6148 women and 5320 men from the Fenland study with objectively measured physical activity from individually calibrated combined heart rate and movement sensing and DXA-derived body fat percentage (BF%) were included in the analyses. We used linear and compositional isocaloric substitution analysis to examine associations of PAEE and its intensity composition with body fatness. Sex-stratified models were adjusted for socio-economic and dietary covariates.
PAEE was inversely associated with body fatness in women (beta = -0.16 (95% CI: -0.17; -0.15) BF% per kJ day kg) and men (beta = -0.09 (95% CI: -0.10; -0.08) BF% per kJ day kg). Intensity composition was significantly associated with body fatness, beyond that of PAEE; the reallocation of energy to vigorous physical activity (>6 METs) from other intensities was associated with less body fatness, whereas light activity (1.5-3 METs) was positively associated. However, light activity was the main driver of overall PAEE volume, and the relative importance of intensity was marginal compared to that of volume; the difference between PAEE in tertile 1 and 2 in women was associated with 3 percentage-point lower BF%. Higher vigorous physical activity in the same group to the maximum observed value was associated with 1 percentage-point lower BF%.
In this large, population-based cohort study with objective measures, PAEE was inversely associated with body fatness. Beyond the PAEE association, greater levels of intense activity were also associated with lower body fatness. This contribution was marginal relative to PAEE. These findings support current guidelines for physical activity which emphasise that any movement is beneficial, rather than specific activity intensity or duration targets.
We measured body fat using X-rays and physical activity by combined movement and heart-rate monitoring in 11,468 UK adults. We examined how both overall physical activity energy expenditure (volume) and the underlying intensity of that activity were associated with body fatness.
Higher levels of physical activity energy expenditure were associated with lower body fatness. Further, for a given level of activity energy expenditure, higher proportions of more intense physical activity were also associated with lower levels of body fatness, but the magnitude of this association was small compared to that of the overall activity volume.
These results support the current public health message to ‘move more’, but additionally suggest that doing the activity more intensely may yield additional health benefits. For example, doing more walking every day would increase activity volume and covering the same walking distance but at faster pace would increase intensity of that volume accumulation.