Intermittent Physical Activity Produces a Leaner but “Sedentary Obese” White Adipose Tissue Phenotype

Abstract

Adipose tissue (AT) dysfunction plays a pivotal role in the development of insulin resistance in obesity. Regular physical activity (PA) is effective in reducing AT mass and inflammation; however, whether intermittent PA affords beneficial effects is unknown. The purpose of this study was to evaluate the influence of intermittent PA on adiposity and retroperitoneal AT expression of genes related to inflammation and oxidative stress. Male C57BL/6 mice (age 5 weeks) were randomly assigned to four groups (n=10/group): low‐fat diet sedentary (LFD‐SED), high‐fat diet sedentary (HFD‐SED), HFD regular PA (HFD‐RPA), and HFD intermittent PA (HFD‐IPA) for 24 weeks. All animals were single‐caged. RPA mice had access to voluntary running wheels throughout the study period, whereas IPA mice had access to running wheels for three‐week intervals (i.e., 3 weeks on/3 weeks off) throughout the study period. Both HFD‐RPA and HFD‐IPA were associated with a similar reduction in retroperitoneal AT mass (~‐24%, p<0.05) relative to HFD‐SED. However, HFD‐RPA, but not HFD‐IPA, exhibited a decrease in retroperitoneal adipose mRNA markers of inflammation (F4/80, CD11c, leptin, VCAM‐1) and oxidative stress (p22phox and p47phox). Collectively, these data suggest that episodic PA over a prolonged period of time leads to a reduction in adiposity albeit with retention of a “sedentary obese” white AT phenotype.