Sitting for too many hours per day, or sitting for long periods without a break, is now known to increase a wide range of health risks, even if one engages in recommended amounts of physical activity. The health risks of prolonged sedentary time - and nurses' role in reducing those risks—are discussed in an integrative literature review and update in the September issue of the American Journal of Nursing.
But while the evidence on the adverse effects of prolonged sedentary time continues to grow, further studies are needed to determine "the most effective and practical interventions for reducing habitual sitting," according to the article by Linda Eanes, EdD, MSN, of the School of Nursing at the University of Texas Rio Grande Valley, Edinburg. She writes, "Nurses have a pivotal role to play in increasing public awareness about the potential adverse effects of high-volume and prolonged uninterrupted sitting."
Health Risks of Too Much Sitting—What's the Evidence?
In recent years, studies have shown a direct relationship between prolonged sitting and the risk of several chronic health conditions. Increased health risks have been reported both for high-volume sitting, such as sitting for seven or more hours per day, and for prolonged uninterrupted sitting, such as sitting for 30 minutes or longer without a break. The health risks of prolonged sitting are independent of whether the person participates in recommended physical activity.
In her review, Dr. Eanes summarizes pivotal studies showing the association between high-volume and prolonged uninterrupted sitting and health risks including cardiovascular disease, diabetes, and all-cause mortality. In conjunction with obesity, sedentary time is also linked to an increased risk of certain cancers, including ovarian, endometrial, and colon cancer.
How does too much sitting increase health risks? Immobility decreases stimulation of weight-bearing muscles, leading to decreased activity of an enzyme (lipoprotein lipase) that plays an essential role in lipid metabolism, including production of high-density lipoprotein cholesterol (the so-called "good" cholesterol) as well as uptake of glucose from the blood. In contrast, breaking up sedentary times with frequent bouts of standing or slow walking may reduce these metabolic risks—although the optimal levels of standing or walking remain unclear.
Nurses and other healthcare professionals now have a new priority: educating patients about the health risks of prolonged sedentary time and making suggestions to reduce and interrupt sitting times. Proposed interventions include using a standing desk or taking frequent walking or standing breaks, as well as the use of computer or smartphone reminders to take brief physical activity breaks during the day.
But questions remain about the most effective ways to address high-volume or uninterrupted sitting, including the "dose-response relationships" between sedentary behavior, taking breaks, and various health outcomes. In contrast to efforts to increase physical activity, merely providing people with information and education might be effective in promoting reduction of sedentary behavior. "Much more research is needed in the field of inactivity physiology," according to the author.
While it's still important to promote regular physical activity, nurses should pay more attention to evaluating total daily sitting time, and to understanding the individual, social, occupational, and community/environmental factors that contribute to it. "Nurses can also actively encourage all patients, regardless of demographics, to balance sedentary behavior and physical activity simply by taking more frequent standing or walking breaks," Dr. Eanes writes. She believes that nurses are well positioned to contribute to research on the health risks associated with prolonged sitting—and the most effective interventions for reducing those risks.
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Linda Eanes. CE, AJN, American Journal of Nursing (2018). DOI: 10.1097/01.NAJ.0000544948.27593.9b