News & Reviews

Currently more than 20% of North Americans work outside of the 8 a.m. to 5 p.m. schedule. Each year, more and more companies move to 24-hour production. However, shift work can wreak havoc with a worker's physical and psychological well-being. Unsuccessfully managed, it can be a source of higher accident rates, increased absenteeism, and lower productivity. Classic health concerns related to shift work include insomnia, sleep apnea, and restless leg syndrome in addition to more subtle, yet equally important, symptoms like anxiety, digestive issues, and irritability. Now a new study published in the Lancet Oncology has found that males and females who work night shifts have higher rates of prostate and breast cancer. Shift work disrupts our circadian rhythm, or sleep cycle, and interferes with melatonin production. Melatonin is a hormone produced during darkness that is thought to suppress tumor growth. Reduced melatonin secretion has been linked to breast cancer in a number of previously published studies. Shift work is now labeled as a “probable cause” of cancer, along with UV rays.

Complete darkness is imperative for restful sleep. If you are a shift worker, ensure your room is completely dark when you have the opportunity to sleep or nap. Even the slightest artificial light from a television, computer, or clock radio can disrupt melatonin production.

Reference: Straif, K., Baan, R., Grosse, Y., Secretan, B., El Ghissassi, F., Bouvard, V., Altieri, A., Benbrahim-Tallaa, L. & Cogliano, V. (2007) “Carcinogenicity of shift-work, painting, and fire-fighting,” Lancet Oncology, 8.