How Atypical Work Schedules Affect Performance

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Monday, December 10, 2012

reduced dexterity and/or productivity in a variety of other work settings. (Drake and Wright, 2011) Night workers are also more likely to have increased absenteeism compared with day workers, especially those experiencing sleep problems. (Drake, et al, 2004)

Shift work and physical health
Shift workers are more prone to developing certain illnesses, including cancer, cardiovascular disease, diabetes, obesity, and gastrointestinal disorders. A number of factors may contribute to these increased risks, including artificial light or lack of sleep inhibiting the normal rise or fall of various hormones during the dark hours of the night. For example, we produce more of the hormone melatonin during the night, and exposure to artificial light inhibits this production. Melatonin has been shown to have a number of positive effects on the body, including lowering blood pressure and decreasing blood clotting, which can help prevent heart attacks and strokes. (Brown, et al, 2009) Melatonin also limits the body’s production of estrogen and other hormones known to fuel breast, prostate, and endometrial cancer. (Viswanathan and Schernhammer, 2009; Costa, et al, 2010)

Cancer
Shift workers are more prone to developing a number of cancers, including breast, endometrial, prostate, and colorectal cancer. (Costa et al, 2010; Stevens, 2009) Large studies have found that women shift workers have up to a 60 percent increased risk of breast cancer, (Davis, et al, 2001; Schernhammer et al, 2001) and a 35 percent greater risk of colorectal cancer. (Schernhammer et al, 2003) On the basis of evidence in both experimental animals and humans, the International Agency for Research on Cancer has classified “shift work that involves circadian disruption” as a probable human carcinogen. (Stevens et al, 2010)

Cardiovascular disease
The longer people work nights or rotating shifts, the more likely they are to develop cardiovascular disease and experience a heart attack or stroke, several studies reveal. (Haupt, et al, 2008; Knutsson, 2008, Knutsson, 1986; Brown et al, 2009) For example, one study found rotating night shift work was linked to a 4 percent increased risk of stroke for every 5 years worked. (Brown et al, 2009) Another 14-year study found that rotating