座位行動と心血管代謝疾患: 実験的研究に基づくエビデンスとメカニズム

Sedentary behavior is ubiquitous in modern lifestyles and defined as any waking behavior with an energy expenditure of ≤ 1.5 metabolic equivalents while sitting, reclining, or lying. Epidemiological evidence suggests that high volumes of sedentary behavior are independently associated with an elevated risk of cardiometabolic disease and all-cause mortality. By contrast, a growing body of experimental evidence showing the potential benefits for cardiometabolic risks of reducing and breaking up sedentary time. Therefore, recent physical activity guidelines indicate the importance of reducing and regularly interrupting prolonged sitting. In this narrative review, we summarize the findings from experimental studies that investigated the acute impacts of prolonged, uninterrupted sitting and interrupting sitting on several cardiometabolic risk factors, including vascular function, blood pressure, and glucose metabolism. Here, we highlight experimental evidence from controlled laboratory trials that may lead to a better understanding of biological plausibility, the causal structure of relationships, and potential mechanistic insight on linking sedentary behavior with adverse cardiometabolic outcomes. Our literature review collectively suggests that in addition to increasing moderate- to vigorous-intensity physical activity, reducing sedentary time may contribute to cardiometabolic health. However, the recent evidence remains limited and inconclusive, thus future studies are needed to develop a deeper causal and mechanistic understanding of the biological pathways through which prolonged sitting can adversely influence cardiometabolic health outcomes.