Monday, May 30, 2011

Night shift work is unhealthy

Working the night shift is bad for your health. That’s the conclusion provided by an accumulation of reports from at least the past decade. Unfortunately, millions of Americans and workers in other developed countries (approximately 10-20 percent of workers) are subjected to the extra stress and rigors the so-called graveyard shift puts on their bodies. As outlined by the LATimes in 2008, at least 15 percent of human genes function on a schedule, the circadian rhythm, which makes working during the day more normal. From doctors and nurses to security guards and truck drivers, millions are at risk for cancer, obesity, heart disease, and mental illness simply because of their work schedule.

Overuse of stimulants

In 2005, NPR interviewed an emergency room physician about working the late shift, particularly about how those who do it should be taking better care of themselves. Due to the “late night” and the body’s yearning to sleep when the sun is gone, individuals who work the night shift tend to over stimulate their bodies with caffeine and sugar. This can lead to difficulty sleeping after the shift in the short term, as well as obesity and diabetes over the long term.


The doctor who spoke to NPR also noted how nurses on the night shift don’t necessarily have the healthiest diets. Not all of the same options are available to those who work during the night as those who work when the shops and eateries are open, but the body is also receiving conflicting signals. As summarized by the Wall Street Journal in 2008, researchers have found that the bodies of sleep-deprived adults produce more ghrelin and less leptin, leading to dysregulated appetite suppression and more hunger.

Obesity comes with its own set of issues, including heart disease, sleeping problems, respiratory problems, reproductive disorders, and gall bladder disorders. Cortisol is also not kept in check properly, which may have an exacerbating effect. As noted by the LATimes, night shift workers have 40 to 50 percent higher rates of heart disease, which includes diabetes. A 2009 study reiterated this finding.


Since 1987, researchers have tossed around the idea that late nights might be linked to cancer. In 2007, the World Health Organization and American Cancer Society added “shift work” to the list of potential carcinogens due to potential links of the overnight shift with cancer (see MSNBC report in 2007 for more information on the background of this decision). Breast, prostate, and colon cancers have all been implicated.

The culprit appears to be melatonin, which is usually produced when a person sleeps at night and has been shown to suppress tumor growth. With the circadian rhythm thrown out of balance and individuals being exposed to artificial light during melatonin production hours, production is decreased, reducing its protective effects. Potential imbalances in DNA replication and repair, and even insulin production to digest food in the middle of the night, have been considered as potential explanations for decreased immune function and increased tumor rates.

Stress and other problems

-As noted in several studies and the LATimes, female shift workers have higher rates of miscarriages and low birth weight babies.

-Neurotransmitters are regulated by the circadian rhythm, resulting in higher rates of mental illness among night shift workers, including anxiety and depression as outlined by the British Medical Journal Occupational and Environmental Medicine in 2001.

-Disruption in home and social life, which can affect stress levels and mental health.

-Poor performance due to all other factors noted above, which can lead to safety issues (and thus health issues).

How to combat the health issues

Exercise and dietary considerations are important for preventing obesity and its related conditions. In addition, light therapy for those who work at night may aid in melatonin production. Napping 20-60 minutes just before a shift can be therapeutic without affecting sleep after the shift.

Sleep experts who talked to NPR in 2005 suggested rotating shifts, specifically forward rotation (one week days, one week evenings, one week nights, one week days, etc.). However, the rotation may increase the body’s physiological imbalances. Keeping the same schedule during days off when working late night for long-term could be helpful - though many who are quoted on the matter simply recommend not working the night shift.

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