Raiber L, Christensen RAG, Randhawa AK, Jamnik VK, Kuk JL. Do moderate to vigorous intensity accelerometer count thresholds corresponds to relative moderate to vigorous intensity physical activity? Appl Physiol Nutr Metab. 2018 Sep 24:1-7. doi: 10.1139/apnm-2017-0643
From the authors:
In research, physical activity is commonly measured using either self-report questionnaires or physical activity monitors that measure movement. Previous, research has shown large discrepancies between objective and subjective measures of physical activity assessment, particularly for those with obesity. These differences are thought to be due to an over-reporting of physical activity by those with obesity. Although physical activity monitors are seen to be the gold standard, this approach may bias activity assessment those with obesity. We show that accounting for differences body weight and cardiorespiratory fitness reduces the reporting differences seen between normal weight and obesity. Further, accounting for cardiorespiratory fitness in physical activity monitor algorithms reduces the duration of physical activity assessed for all body weight categories and sexes. This may suggest that there are issues with applying the current accelerometer algorithms to estimate physical activity at a population level and may particularly bias against those with lower fitness, such as those with obesity.