Stand Up for Your Health: A Randomized Study - Abstract: Sedentary behavior is becoming increasingly prevalent with the expansion of a ‘work from home’ culture, most recently driven by the COVID-19 pandemic. We now spend more time sitting than in all other activities combined. This increased chair dependency, including a reduction in occupational energy expenditure over the past 5 decades, has contributed to the epidemic of chronic disease, including metabolic syndrome, cardiovascular disease, and type 2 diabetes mellitus (T2DM). Several studies, including a large meta-analysis of 18 studies totaling 794,577 subjects, concluded that sedentary behavior mediates T2DM. The CDC predicts that if current trends continue, as many as 1 in 3 U.S. adults could have diabetes by 2050. At present, 9% and 34% of U.S. adults have T2DM and prediabetes, respectively. Although we excluded diabetics in our pilot study, 11 of the 15 overweight or obese subjects were found to have some insulin resistance by HOMA-IR at baseline (BMI positively correlates with the incidence of T2DM). In our pilot study of 15 subjects with sedentary office jobs, 6 months of sit-stand desk use resulted in a 23% improvement in insulin resistance, most substantial in those who decreased daily sitting by over 90 minutes/day. Additional improvements in vascular endothelial function and triglyceride levels were seen without any change in exercise activity, step counts, or body weight. These findings not only corroborate epidemiologic findings on this topic but suggest causality and warrant a randomized control trial. This strategy of replacing sitting desks with a sit-stand desk has significant potential to reduce cardiometabolic risk in the 70% of adults categorized as overweight or obese, the majority of whom have insulin resistance. This intervention could have substantially strong impact, amplified by the COVID-19 pandemic, given nearly 80% of U.S. jobs are sedentary. We hypothesize that adult subjects at-risk for diabetes will improve insulin sensitivity, metabolic and vascular (endothelial) health with a sit-stand desk intervention at work (whether in the office or at home), in the context of a randomized, controlled trial. We will randomize 198 sedentary office workers with a BMI≥25 at risk for T2DM in a 1:1:1 ratio of three groups: (a) sit-stand desk intervention targeting 2 hours standing per day; (b) sit-stand desk intervention targeting 3 hours standing per day; or (c) control arm over 6 months. Objective quantification of sitting and standing times will be performed with sophisticated activity monitors and smartphone activity logs. We will ascertain if the sit-stand desk improves insulin sensitivity and metabolic health and whether there is a dose-dependent relationship with changes in sedentary time (Aim 1). We will determine if the intervention improves vascular endothelial function locally (superficial femoral artery FMD) and/or systemically (assessing brachial artery FMD resilience) (Aim 2). Sub-aims will assess changes in circulating triglycerides and free fatty acid levels and correlate with changes in endothelial function. Affirmative findings would move the field forward by demonstrating that a readily adoptable workplace intervention focused only on reducing sitting time alone, reduces cardiometabolic risk.
