Too much sitting and dysglycemia: Mechanistic links and implications for obesity

Prolonged sitting – at work, during transport and in front of screens in the domestic environment – is now an ubiquitous element of everyday life, and is known to be linked to detrimental cardiometabolic health outcomes, including obesity, dysglycemia, diabetes and cardiovascular disease. Observational evidence suggests higher total sitting time and sitting time accumulated in prolonged bouts are associated adversely with cardiometabolic risk profiles, and with premature death from cardiovascular disease and all causes. A growing body of experimental evidence supports this observational evidence: there are acute beneficial changes in postprandial glucose metabolism when prolonged sitting is interrupted by brief bouts of physical activity, which can be proportional to the degree of dysglycemia. A strong mechanistic candidate underlying these associations is lack of muscle contractile activity; reduced skeletal muscle glucose uptake via reduced translocation of GLUT4 to the cell surface and lowered efficiency of insulin. Future studies are needed to confirm these relationships and to develop broader mechanistic insights on the biological pathways through which prolonged sitting can adversely influence cardiometabolic health outcomes.