Sedentary Behavior as a Mediator of Type 2 Diabetes

Abstract

Over the past 5 years, the fastest growing new area of physical activity research centered around the concept that the large amount of time people spend sitting inactive may have significant physiological consequences hazardous to human health, including risk for type 2 diabetes and poor metabolism of lipids and glucose. Meta-analysis (10 studies) suggest there is a 112% greater relative risk associated with a large duration of sedentary behavior for type 2 diabetes. Meta-analysis also indicates significantly greater odds for metabolic syndrome. We also summarize results for 7 studies using objective measures of total sedentary time and focusing on cardiometabolic risks in persons at high risk for type 2 diabetes or already diagnosed with type 2 diabetes. The underlying hypothesis introduced in 2004 by the inactivity physiology paradigm, has been that frequent and abundant contractile activity by certain types of skeletal muscle can have a potent influence on key physiological processes, even when the intensity is below that achieved through exercise. We explain some of the mechanisms for why the metabolism in slow-twitch oxidative skeletal muscle is key for understanding the healthy responses to low intensity physical activity (LIPA). Findings from objective measures from inclinometry indicated that the quartile range for weekly sedentary time is ~29 hours/week. The total daily time that people sit, stand, and accumulate non-exercise steps is independent of traditionally recommended moderate-vigorous physical activity (MVPA). The large amount of sedentary time associated with risk for disease can only be reduced significantly with safe and non-fatiguing LIPA, especially in the most at risk proportion of the population. Importantly, experimental studies are starting to indicate that it will be especially insightful to understand the acute dose-response effects of LIPA in order to understand why reducing sedentary time can improve lipid and glucose metabolism for the prevention and treatment of chronic disorders related to type 2 diabetes.

Dose–response relationships between sedentary behaviour and the metabolic syndrome and its components

“…Our finding of effect modification by MVPA on the relationship between SB and the components of triacylglycerol, HDL-cholesterol and fasting glucose implies that SB and MVPA may exert their effects through similar pathways for some biomarkers but different pathways for others. This notion is supported in a review of several studies by Hamilton et al [29], who demonstrated that the expression of some genes important for preventing diabetes and other metabolic risks is resistant to being restored after 12 h of inactivity, while the expression of others is not. In particular, a study examining the activity of lipid phosphate phosphatase-1 (LPP1) suggested that gene expression may be suppressed in response to chronic sitting despite participation in 1 h/day of vigorous exercise [30].…”

Back to the Future. Metabolic Effects of a 4-Day Outdoor Trip Under Simulated Paleolithic Conditions – New Insights from The Eifel Study

“…In affluent societies, food is not only consumed in order to maintain energy balance but also for hedonic attributes independent of energy status, and this might be one of the reasons for calorie excess [49,50]. This situation is then compounded by prevalent physical inactivity [22,51] and sleep disturbance [52], all combining to lead to severe metabolic disturbances such as metabolic syndrome and T2D mellitus over time [21,53].…”

Sedentary behaviour in rheumatoid arthritis: definition, measurement and implications for health

“…In particular, there is evidence that implicates SB as a precursor of heightened systemic inflammation in both healthy and clinical populations, irrespective of levels of the anti-inflammatory effect of physical activity [8][9][10][11]. Indeed, there now exists a considerable amount of evidence demonstrating SB to be an independent risk factor for cardiovascular disease, the metabolic syndrome, sarcopenia and Type 2 diabetes, all of which have chronic systemic inflammation in common [9,10,[12][13][14][15][16]. These independent health effects may result from differences in the acute and chronic physiological responses to sedentary behaviour vs. physical activity engagement [17].…”