Around 5.7 million people in the United States regularly work the night shift or a rotating shift, according to a 2004 report from the Bureau of Labor Statistics. Most people work the night shift because it is a job requirement, but others choose it for personal preference or better pay. While working nights is convenient for some people, it can cause sleep problems and fatigue while increasing the risk of developing certain chronic health problems.
Obesity and Metabolic Syndrome
Metabolic syndrome involves a cluster of abnormalities, including increased blood pressure, abnormal cholesterol levels, elevated blood sugar and extra body fat around the waist. Night shift workers are at a higher risk of developing metabolic syndrome because they are typically sleep-deprived and their schedule is out of alignment with the body's internal clock -- which regulates metabolism and controls certain hormone levels. The modified eating schedule of night shift workers also contributes to metabolic syndrome, as well as obesity, because the body processes food differently when eaten during the night than during the day.
Studies have shown that working the night shift leads to a 40 percent excess risk of developing heart disease -- including heart attacks and other symptoms of coronary artery disease -- when compared to day workers, according to a review published in the journal "Occupational Medicine" in March 2003. Metabolic changes that occur while working a night shift may provide some explanation for this increased risk. For instance, night workers have been shown to have higher blood cholesterol levels -- a risk factor for heart disease -- when compared to the rest of the population. Obesity and metabolic syndrome also increase the risk of coronary artery disease.
People who work the night shift experience digestive problems more frequently than those who work during the day. Common digestive complaints include abdominal pain, constipation and diarrhea. An article published in "Occupational Medicine" in March 2003 reported that 2.38 percent of night shift workers developed stomach ulcers, compared to 1.03 percent of day shift workers. The risk for ulcers in the small intestine was nearly double in night shift workers.
The sleep deprivation that usually results from working nights can cause lapses in judgment, reduced cognitive ability and decreased attention, making night shift workers more vulnerable to car accidents and work errors. Night shift workers -- specifically those who work 12-hour shifts -- are also more likely to smoke, abuse alcohol and suffer from fatigue. Early research shows that working the night shift may increase the risk of developing certain forms of cancer. In addition, working nights during pregnancy has been associated with an increased risk of miscarriage, premature birth and low birth weight.
Adaptation is the key to helping the body cope with a night shift schedule. For short-term night shift work, one can resist the internal clock by using stimulants like caffeine to keep awake during the night and then focusing on quality sleep during the day. Long-term night shift workers often find that the best option is to completely reset the body's internal clock, which may involve timed exposure to bright lights during the night shift, wearing sunglasses to avoid light exposure in the morning and sleeping in a dark bedroom.
- Occupational Medicine: Health Disorders of Shift Workers
- Proceedings of the National Academy of Sciences of the United States of America: Adverse Metabolic and Cardiovascular Consequences of Circadian Misalignment
- Occupational Medicine: Shift Work: Coping With the Biological Clock
- American Psychological Association: The Risks of Night Work
- Bureau of Labor Statistics: Workers on Flexible and Shift Schedules in May 2004