If you are a woman and you work overnight shifts the news is not good. Two new studies into the effects of shift work on health outcomes have reinforced the negative consequences of following this type of schedule. The first study further established the link between sleep deprivation and an increased risk for breast cancer. The second study solidified the link between shift work and sleep deprivation and the increased risk of obesity and diabetes. Both together paint an unpleasant picture for middle-class women who may already be struggling to make ends meet in their shift-work jobs.
When it comes to shift work, the increased risk for disease and other problems seems to stem from a mismatch between the body’s clock and its normal sleep-wake pattern with the body’s circadian rhythm playing an important role. This internal clock controls some key bodily functions including the sleep-wake cycle, body temperature, and the secretion of hormones. When this clock is disrupted by a shift-work schedule, it doesn’t perform optimally which can lead to hormonal imbalances and difficulty sleeping during the day. Unfortunately, this clock is also very difficult to reset because it is tightly aligned with the rising and setting of the sun. This means that it can be very difficult for shift workers to get the sleep they need during the day which means that many women who work off-schedules are not getting the quantity or quality of sleep they need to be healthy.
The first study sought to determine if working the night shift disrupted melatonin levels causing an increase in the risk for developing breast cancer. The study included a total of 353 participants, 172 were night shift nurses and 151 were nurses who worked on the day shift. All participants were female and ranged in age from 20-49. The team used specific tests to determine the presence and levels of specific metabolites, hormones, and other chemicals in the participant’s samples. Samples were taken during the day and night in order to encompass the full range of experience for both groups of women. The results were informative as the night-shift nurse group had a substantially lower amount of one chemical than the day shift nurses. Additionally, the team found that even on the nights when the night shift nurses had the night off and slept a normal schedule, the amount of this chemical in their samples did not rise. The team concluded that these findings support the theory that shift work, even more so than sleep deprivation, may be an important risk factor for the development of breast and other cancers.
The second study further established the link between sleep and both obesity and diabetes. These findings, in line with the first study, found that when people tried to sleep during the day or against their biological clock they were at an increased risk for becoming obese. However, this study also shows that getting too little sleep and suffering from sleep deprivation does the same thing, increasing the risk for obesity and diabetes, among other things. This study showed that both sleep challenges could independently contribute to the development of long-term health problems.
Based on the findings in these two studies, there is no question that women who work off-hour shifts are suffering the consequences of a schedule that is not aligned with their biological clock or circadian rhythm. As additional research is conducted, the hope is that the increased understanding of how these are related will provide better preventative care and more effective treatment programs.
- Erratic Sleep May Contribute to Obesity and Diabetes (valleysleepcenter.com)
- The Connection Between Sleep Deprivation and Obesity (valleysleepcenter.com)
- Does Sleep Apnea Cause Cancer? (valleysleepcenter.com)