The following are some details of research carried out.
Employees working split shifts could be harming their health, Health and Safety Executive research has suggested.
A study found offshore oil rig workers who worked seven nights then seven days had a higher risk of heart disease than those who stayed on days or nights.
Split-shift workers were also more tired and inattentive, New Scientist magazine reported.
Occupational health expert Cary Cooper said involving staff in designing shift patterns reduced health problems.
People who feel they have some control over their working lives are then less likely to have illnesses
Professor Cary Cooper, Lancaster University
Researchers from Cardiff University and the University of Guildford in Surrey examined the health of 45 offshore oil rig workers.
Both compared the effect of the two main shift schedules on the men.
Over two weeks, they may have been asked to work 12 hour day-shifts or night-shifts.
But the other group worked a split-shift of seven night-shifts followed by seven day-shifts. Many preferred this pattern because it got them into the habit of night-time sleeping before they went home.
However, the researchers found it was worse for their health.
Urine tests from men working the split-shift pattern showed levels of melatonin, a hormone which regulates sleep and which is normally secreted at night, did not become synchronised to new sleep times after shift changes.
The men also had higher levels of fatty acids circulating in their blood after meals, compared with the day-shift or adapted workers, indicating they were at higher risk of heart disease, diabetes and other metabolic disorders.
Josephine Arendt, a chronobiologist from the University of Surrey, who carried out one of the studies, told New Scientist magazine: "The swing shift is the killer."
Andrew Smith of Cardiff University, who carried out the second study, said workers should try to avoid split-shifts and other schedule changes that put their body clocks out of kilter.
Alison Shaw, Cardiac Nurse at the British Heart Foundation (BHF) said: "Adapting to different sleep patterns can be a problem, as they can affect melatonin - a hormone that regulates sleep, and takes some time to come back to synchronised levels after a shift switch.
"Also, access to healthy foods and adequate breaks whilst working shifts is vital. Snacking on high fat, high calorie foods and smoking can increase your risk of CHD."
Twenty percent of workers are unable to tolerate shift work. Daily physiologic variations termed circadian rhythms are interactive and require a high degree of phase relationship to produce subjective feelings of wellbeing. Disturbance of these activities, circadian desynchronization, whether from passage over time zones or from shift rotation, results in health effects such as disturbance of the quantity and quality of sleep, disturbance of gastrointestinal and other organ system activities, and aggravation of diseases such as diabetes mellitus, epilepsy and thyrotoxicosis. Worker selection can reduce the number of health problems resulting from shift work. The periodic examination of shift workers is recommended.
The Health Effects of Shiftwork
Most health problems attributed to shiftwork are believed to result from the fact that it requires people to invert the normal cycle of being awake and active during the day and sleeping at night.
For most people, the body’s circadian rhythms -- daily fluctuations in body functions such as body temperature, hormone production and blood pressure -- stay oriented to daytime living. Body temperature, for example, rises in the afternoon and dips during the overnight hours, while the production of the hormone melatonin follows the opposite pattern.
It’s different for shiftworkers. Working consecutive night shifts prompts circadian rhythms to slowly begin to shift, but factors such as the cycle of sunlight and darkness, the tendency to revert to daytime living on days off, and the need to rotate shifts prevent complete adaptation.
Living and working "out of synch" with circadian rhythms -- as well as constantly shifting them -- places stress on one’s body, potentially leading to health problems such as sleep disorders, stomach ailments, heart disease, mental health problems, increased mortality and risks specific to women's health.
9 Tips For Minimizing Shiftwork’s Health Effects
1 - Offer orientation and/or periodic training covering circadian rhythms and coping strategies for shiftwork.
2 - Make sure shiftworkers have access to lifestyle programs aimed at improving diet, stopping smoking and exercising regularly.
3 - Provide 24-hour cafeteria service or make healthy snacks available around the clock.
4 - Permit on-the-job exercise and/or have an on-site exercise room.
5 - Include a mental health component in your Employee Assistance Program.
6 - Select a shift schedule that minimizes wear and tear on workers’ bodies.
7 - Have a room with cots or easy chairs where workers can nap before and after work.
8 - Make job applicants aware that shiftwork may exacerbate pre-existing medical conditions.
9 - Identify and treat shiftworkers who have sleep disorders such as sleep apnea and narcolepsy.
For more information about what night workers can do to maintain their health, see the Working Nights Health & Safety Guide, available from Circadian Information (www.circadian.com).
The Benefits of Shiftwork
While shiftwork has its drawbacks, it's important to recognize that it has advantages too. It is worthwhile to highlight the benefits of shiftwork, many of which are family related.
Perhaps the biggest advantage of working at night is that public places are less crowded during the daytime. You can breeze through shopping malls, grocery stores and banks without having to wait in long lines. For recreation, movie theaters offer daytime discounts and you don't have to worry about people rushing you through the golf course.
Similarly, by working at night, you may avoid one of the worst plagues of
Source: Working Nights Health & Safety Guide (Circadian Information, Lexington, Mass. USA, www.circadian.com).
for more on this go to the following links
http://news.bbc.co.uk/2/hi/health/4466555.stm
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1274227