The Danger of Sitting Down: A Summary of the Health Risks of Excessive Sedentary Behavior

The health benefits, both cognitive and physical, of regular exercise are widely documented. Exercise reduces levels of cortisol, a hormone associated with the onset and severity of many diseases (Cornil, De Coster, Copinschi & Franckson, 1965; Cohen & Williamson, 1991). Overall, observational studies show that regular physical activity inversely relates to disease outcomes for diseases including hypertension, thromboembolic stroke, heart disease, type 2 diabetes, osteoporosis, obesity, and colon and breast cancer (Kesaniemi et al., 2001).

Even walking, or household chores such as mowing the lawn or gardening, can favorably alter your risk for issues including high blood pressure, heart disease, and diabetes (National Institute for Diabetes and Digestive and Kidney Diseases). However, more intense exercises – such as running, biking, swimming, and team sports - generally offer greater rewards.

Exercise also bears fruit in the domain of mental health. Evidence now validates the use of exercise as a treatment component in cases of clinical depression. Further, it can boost physical self-perceptions, self-esteem, and mood states.

Weaker data indicates that exercise can improve cognitive function, predominantly in the form of reaction time (Fox, 1999). Finally, greater levels of exercise also correlate with more social connectedness (Armstrong & Oomen-Early, 2009).

In recent years, the United States government has launched several programs aimed at encouraging greater levels of physical activity (in tandem with better diets) across the country. Let’s Move, a youth targeted campaign spearheaded by Michelle Obama, fosters “active families, schools, and communities” through gimmicks like the “Presidential Active Lifestyle Award” and the first lady’s #GimmeFive Twitter campaign, along with appearances by Mrs. Obama herself on the popular youth television channel Nickelodeon (Let’s Move). More local campaigns, such as “Shape Up Somerville” in Massachusetts, also remain on the rise (Somerville, Massachusetts).

Indeed, current research suggests that this increased emphasis on promoting exercise is entirely justified. At the time of a 2007 study, only 49.1% of US adults satisfied the Center for Disease Control/American College of Sports Medicine physical activity recommendation (Haskell et al., 2007). With 34.9% of all US adults now classified as obese (78.6 million Americans), these programs rightly address an issue causing an annual $147 billion burden to the US (Ogden, Carroll, Kit, & Flegal, 2014; Finkelstein, Trogdon, Cohen, & Dietz, 2009). However, alongside people’s efforts to improve their health through adequate exercise and proper diet, an enemy to improved health lurks: sitting – a rarely talked about yet increasingly significant problem.

The average US adult spends 7.7 hours per day engaging in sedentary behaviors (defined as waking time spent sitting, reclining, or lying down) (Matthews et al., 2008). This figure is only expected to rise due to future technological advancements, greater dependence on sedentary modes of transportation, and less physically demanding jobs (Brownson & Boehmer, 2013). Data collected from a number of laboratories confirms that sitting can be fatal. Too much sitting is associated with a 24% increased risk of colon cancer, a 32% increased risk of endometrial cancer, and a 21 percent increased risk of lung cancer (Schmid & Leitzmann, 2014). Furthermore, sitting time correlates to risk for cardiovascular disease, type II diabetes, obesity, and general mortality (Biswas et al., 2015; Patel et al., 2010). Katzmarzyk and Lee (2012) speculated that average life expectancy in the U.S. would increase by two whole years if excessive sitting time was reduced by just three hours per day.

Regardless of physical activity level, increased time sitting corresponds to an increased risk of mortality.

Often misunderstood, too much sitting is not synonymous with too little exercise. In fact, a person considered highly active might sit far too much throughout their day: picture an individual who lifts weights in the morning and runs for two hours in the evening, but sits in the car during their commute and at a desk for seven hours throughout the workday. This individual certainly meets physical activity guidelines but might still be at risk for detrimental health outcomes due to excessive sedentary behavior. According to several reports, not even high exercise levels can mitigate the harmful effects of sitting (Schmid et al., 2014; Matthews et al., 2012). It appears that regardless of physical activity level, increased time sitting corresponds to an increased risk of mortality (Biswas et al., 2015; Patel et al., 2015).

Although the biological mechanisms underlying sedentary behavior’s role in disease development require further investigation, adiposity buildup is likely key. On its own, adiposity may facilitate carcinogenesis through increased sex hormones, insulin resistance (an early sign of diabetes), chronic inflammation, and altered secretion of adipokines (Neilson, Friedenreich, Brockton, & Millikan, 2009).

However, adiposity accumulation may also influence other disease pathways. This leads researchers to hypothesize that adiposity is both an independent and mediating variable for disease onset (Lynch, 2010). Other groups speculate that sedentary behavior’s influence on plasma triglyceride clearance (Bey & Hamilton, 2003) and lipoprotein lipase regulation, due to lack of muscle contraction, represents a major contributing factor (Hamilton, Hamilton, & Zderic, 2007).

Though the undeniable association between higher risk for disease and greater time spent sitting paints a bleak picture, research investigating the manner in which sitting time is accumulated offers hope. In one study, one to two minute breaks from sitting correlated with smaller waists, less insulin resistance, and lower levels of inflammation (Csizmadi, Lo Siou, Friedenreich, Owen, & Robson, 2011). A different, cross-sectional study showed that more frequent breaks in sedentary time significantly correspond to smaller waist circumference and lower plasma glucose levels and loosely coincide with a smaller body mass index and lower levels of triglycerides (Healy et al., 2008). All of the aforementioned areas are risk factors for detrimental health outcomes including cancer and metabolic disorders. Together, these reports hint that breaks in sedentary time may become a primary method to protect against its adverse effects.

Despite the pervasive health risks associated with sitting and documented means to temper them, even workplaces, where people accumulate most of their sedentary time, have enacted very few changes. On the whole, employers do not brainstorm ways to lessen the time their employees spend sitting and employees do not clamor for opportunities to escape the confines of their office chairs.

Employee absences can inflict huge blows to organizations in terms of cost and productivity. To deal with an absence employers frequently hire replacement workers or shift responsibility to other employees (often incurring overtime payment). These actions increase company costs, disrupt normal workplace flow, and raise stress levels. Productivity decreases simultaneously because replacement employees work only 71% as efficiently as their absent equivalents (Bass & Fluery, 2010).

Importantly, reports show that workers overweight or obese (body states linked to time spent sedentary (Stamatakis, Hirani, & Rennie, 2009) use two to three more sick days per year than their normal weight counterparts (Tucker & Friedman, 1998; Finkelstein, Fiebelkorn, & Wang, 2005). Considering the substantial blow that ailing employees can deal to companies, it seems more likely that this lack of workplace changes results from ignorance towards exorbitant sitting’s negative health risks rather than a deliberate decision to avoid company policy modifications. Then, it is probable that considerable workplace changes could take place following heightened emphasis on the sedentary behavior’s confounding health risks.

Education is the primary method employers can use to reduce workplace sedentary time; if more workers knew about the apparent perils of too much sitting, more would likely initiate behavioral changes. For example, a recent survey found that 18% of employees do not leave their desks for lunch break and another 10% do not even take a lunch break at all (CareerBuilder).

Employees who skip lunch or eat at their desks miss out on an important break from sedentary time, which could jeopardize their long-term health.

Brushing aside the negative metabolic consequences of skipping meals (Carlson et al., 2007), workers who skip completely or eat lunch at their desk miss out on a rare break in sedentary time. These same employees might choose to relocate for lunch, however, if informed of the benefits of breaking up their sitting. Employers can feasibly obtain this outcome by integrating recommendations for breaks in sedentary time into existing employee wellness and health education programs. The growing list of health risks due to excessive sitting legitimizes its place alongside platforms toward tobacco cessation, weight and stress management, and exercise and diet adjustment.

Companies can also modify workplace structure and policy to facilitate more breaks in sitting time – primarily, through the introduction of height adjustable, sit-stand desks into the office. Since scientists have long established that standing on its own increases total energy expenditure and resistance to fat gain, it makes sense that standing desks can benefit workers (Levine, Eberhardt, & Jensen, 1999). Recent data indicates that standing desks significantly increase workers’ levels of moderate to vigorous physical activity (Miyachi et al., 2015).Continued on Next Page »