The United States has increasingly become a 24/7 society. With the Internet and the advent of things such as 24-hour shopping, the number of 24/7 work situations where night shifts are required has accelerated. Some 15 million workers work the night shift across the country.

The night shift, however, can pose risks to workers. Studies have linked the night shift to adverse health risks and increased safety risks. For example, a study has found that working the night shift increases the risk of breast and colon cancer in women and prostate cancer in men. Researchers involved in the study theorize that shift work interferes with normal circadian rhythms, thus suppressing immune system function and reducing the production of melatonin (a hormone that is believed to inhibit cell damage). Another study on workers' health found that women working night shifts are more likely to be forced into early retirement because of poor health and disability. Still, other studies have linked the night shift to heart disease, peptic ulcers, and pregnancy complications. With respect to safety, a program by the Liberty Mutual Research Institute found that work-related injuries increased more than 15 percent on afternoon shifts and almost 28 percent on the night shift, as compared to the morning shift.

We're likely to see more nightshift work, especially with globalization and the continued use of the Internet, so what can an employer do to address hazards associated with the night shift? Here are points employers should consider when examining the health and safety of their nightshift workers:

Set a fixed night shift rather than a rotating one. Employees who work a rotating shift schedule get less sleep than those who work fixed shifts, according to a study published this month in Occupational Health & Safety. The study's authors theorize that working a fixed shift, rather than rotating shifts, allows people to better adjust their circadian rhythms to working the night shift. The caveat to this was that when employees went back to daytime schedules on their off days, they significantly reduced the benefits of working a fixed night shift.

Encourage employees to get enough sleep. Educate employees on the importance of getting enough sleep, and give them tips on how to accomplish it, including keeping the same sleep schedule on their days off, establishing sleep routines (i.e., bedtime routines) to help them fall asleep more easily, and using dark curtains when sleeping during the day. Also, warn against the use of over-the-counter sleep medications and alcohol as sleep aids, as these can actually exacerbate sleep problems in the long term.

Try to limit shift work to four consecutive nights followed by a couple of days off. The Liberty Mutual Research Institute study found that the average risk for injury was 36 percent higher on the last night of a four-night shift, and that risk increases incrementally over each night on the job.

Pay attention to the work environment. To improve alertness levels for nightshift workers, ensure that work areas are properly lit (i.e., brighter light is better than dim) and are kept cool but comfortable. Also, continuous humming or droning noises can make people drowsy, as can repetitive tasks. Whenever possible, muffle or mask these noises (by playing music of varying tempos, for example), and rotate employees among jobs.

Allow shorter, more frequent breaks. Studies have found that injury risk to employees on the night shift increase as the time between breaks increases. Rather than giving one or two long breaks during the shift, give employees three or four shorter breaks, where possible.

Discuss diet with employees. Digestive processes are affected by circadian rhythms, and nightshift workers have been shown to have an increased risk of gastrointestinal problems. Encourage employees to eat healthy, low-fat foods (such as fruits, vegetables, whole grain carbohydrates, and lean meats) during meal and rest breaks to reduce digestive problems and also to help maintain alertness while working. Employers may want to consider, for example, replacing "standard" snack machines stocked with chips and candy with refrigerated snack machines which stock fruit and low-fat cheese and yogurt. And although caffeinated beverages may help with alertness during the shift, they can affect employees' sleep after the shift and can also cause digestive problems.

The night shift appears to be here to stay. As employers have more employees working the graveyard shift, reducing the health and safety risks associated with 24/7 operations must be addressed.