By Reino Gevers Jul 6, 2009, 3:08 GMT
Hamburg - Night shift work is strenuous, but the potential health problems, such as obesity and cardiovascular disease, may be much bigger than previously thought, according to a recent study.
The study conducted by Harvard University in Boston and published in the online edition of Proceedings of the National Academy of Sciences revealed a higher risk of diabetes, obesity and cardiovascular disease among night shift workers.
Blood levels of leptin were down, which increases obesity risk in the long term, the report said. Other symptoms included a higher level of the stress hormone cortisol and higher blood pressure.
'There is convincing evidence for an increased risk of cardiovascular and metabolic complications associated with shift work, but the underlying mechanisms were largely unknown,' said Frank Scheer, a neuroscientist involved in the project.
The researchers studied five women and five men who voluntarily underwent a progressive jet lag, eating and sleeping on a 28-hour schedule. The participants ate four identical calorie meals.
Past studies conducted on animals who underwent changed day and night sleeping patterns even caused premature death.
Results of two studies on night shift work published in 2001 also suggested an increased risk of women developing breast cancer, possibly because prolonged exposure to light at night interfered with production of melatonin, a hormone produced in response to darkness.
Other data also suggested that working a rotating night shift at least three nights per month for 15 or more years may increase the risk of colorectal cancer in women.
People working nights shifts can however do a lot to minimize the negative effects on the body. Here is some advice:
- Night shift workers get less sleep than normal workers. Sleeping in a dark and quiet environment during the day can improve sleep and prevent early morning sunlight from activating the internal daytime clock.
- Drink less fluids before going to bed and avoid alcohol and coffee.
- Exercise regularly after sleep and work.
- Eat only light meals during the night shift and avoid big meals before going to bed.
- Employers can install brighter lighting - a well-lit workplace tells the body that it is time to be awake and alert. Employers should also allow time for short power napping breaks of 15-20 minutes and provide night shift workers with more days off to recuperate.
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