How Sleep and Work Affect Our Health: A HealthCentral Explainer

ATsai Editor
  • It makes sense that how we sleep affects our performance at work. Feeling tired from a restless night of sleep - or having a job that requires shift work - can leave us less alert and unable to focus. However, recent research also suggests that our job-sleep lifestyle can affect our overall health.


    Caffeine can prevent truck drivers from having accidents

    Truck drivers have to contend with long driving periods, sitting in the same position for hours, and experiencing a monotonous set of conditions, which can all lead to drowsiness and increase the risk for crashes. But recent research suggests that consuming caffeine can improve alertness and prevent crashes even if a driver hasn’t been able to get much sleep.

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    Researchers looked at long distance truck drivers in Western Australia between 2008 and 2011. They compared 530 drivers who had crashed their vehicle while driving long distances to 517 drivers who had not crashed in the past year. They found that 43 percent of all the drivers consumed caffeine to prevent tiredness, and those drivers reduced their risk of crashing by 63 percent.


    They also found that the drivers who had not crashed in the last year were on average two years older and had more experience driving long distances, but they got fewer hours of sleep each night. Researchers warn that the caffeine advantage works only for a short period of time, and frequent breaks, napping and proper working hours are all important.


                [SLIDESHOW: 6 Things That Could Be Causing Your Fatigue]


    Night shift work could be linked to ovarian cancer

    Working the night shift could be an important risk factor for ovarian cancer, according to a recent study published in Occupational and Environmental Medicine. Researchers looked at 1101 women with advanced epithelial ovarian cancer (389 with borderline disease), and compared them to 1832 women who did not have ovarian cancer. The women were between 35 and 74 years old, and were asked the hours they worked and if they had ever worked a night shift.


    They found that among the women with invasive cancer, around 27 percent had worked a night shift, compared to 32 percent of those with borderline disease and 23 percent of the comparison group. The night shift was also associated with a 24 percent increased risk of developing advanced cancer and a 49 percent increased risk of developing an early stage of the disease, compared to those who worked during the day.  In addition, only women 50 years old and above had a significantly greater chance of developing ovarian cancer if they had worked night shifts.


    Previous research has found a connection between shift work and an increased risk for breast cancer, and the International Agency for Research on Cancer has named shift work as a cancer causing agent due to the disruption to the body’s circadian rhythm, according to Medical News Today.


    When a shift starts can affect alertness

    Shift start times may be just as important to worker’s sleep and alertness on the job as the number of hours worked, according to research presented in 2010.  Researchers found that shifts beginning between 8 p.m. and midnight caused more fatigue, poorer work performance and less total sleep in 24 hours than any other shift start time. They believe that shifts starting during this time period do not allow for pre-shift sleep because of the body’s early evening circadian process.


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    Researchers used a mathematical model to predict the effect of shift start time on total sleep time when a person is off the shift for a 24-hour period, as well as predicting on-shift fatigue per day. Then, 24 hypothetical shift work scenarios were created with start times that varied by one hour for 24 hours.


    Each hypothetical workday lasted for six days, for nine-hour shifts, and that took into account the hour before and after the shift. The researchers found that the minimum amount of job fatigue occurred when the shift start time was 9 a.m., and the maximum fatigue occurred when the shift began at 11 p.m. In addition, shift work that started after midnight showed a sudden decrease in predicted fatigue compared to those that started just before midnight. Researchers say this is because shifts that start after midnight allow workers to sleep until right before the shift starts, meaning they are better rested before work.


    Researchers say that limitations on hours worked should take into account the start time of the shift.


                [SLIDESHOW: 5 Health Issues that Arise from Sleep Deprivation]


    Burned out employees have increased risk of heart disease

    Demanding careers that require longer work hours, fewer vacation days and later retirement can cause job burnout for employees. This kind of physical, mental and emotional exhaustion has been found to increase the risk of obesity, insomnia and anxiety, and according to new research, heart disease.


    Researchers looked at 8,838 seemingly healthy employees between the ages of 19 and 67. Participants underwent routine health examinations and were followed for an average of 3.4 years. They were measured for burnout levels and examined for signs of coronary heart disease, according to Medical News Today. The follow-up exams revealed 93 new cases of coronary heart disease. Researchers found that burnout was associated with a 40 percent increased risk of developing the disease, but the 20 percent of participants with highest burnout levels had a 79 percent increased risk.


    Researchers say employers need to promote healthy lifestyles to prevent burnout, which includes exercising regularly, getting seven to eight hours of sleep every night and seeking psychological help, if necessary.



    Glynn, S. (2013, March 21). "Truckers On Caffeine Have Fewer Accidents." Medical News Today. Retrieved from


    BMJ. (2013, March 15). "Night Shifts May Be Linked To Increased Ovarian Cancer Risk." Medical News Today. Retrieved from


    McCann, K. (2010, June 9). "The Best And Worst Work Schedules: Shift Start Times Can Impact Sleep And Alertness." Medical News Today. Retrieved from


    American Friends of Tel Aviv University. (2013, March 15). "Top 20% Of Burnt-Out Employees Have A Dramatically Increased Risk Of Heart Disease." Medical News Today. Retrieved from



Published On: April 01, 2013