It may be time to take the term "graveyard shift" literally. A new study has re-affirmed the old medical suspicion that night work can shorten your life. And before you write off this story as something that should only concern night watchmen and cab drivers, you should know that fully 20 percent of the working population of developed countries earns their living at night. As hard to believe as it sounds, the International Agency for Research on Cancer, a branch of the World Health Organization, is actually going to add night work to its list of probable carcinogens. This concern is nothing new, though. The medical suspicions about the potentially deadly side effects of night work have been around for more than a generation.
Richard Stevens, a professor at the University of Connecticut Health Center, was the first to see a link between the night shift and cancer. He developed his theory while searching for an answer as to why the incidence of breast cancer in women suddenly spiked in the 1930s, when industrialization made a round-the-clock labor force one of the hallmarks of a successful economy. Of course, many doctors and researchers thought that Professor Stevens's theory was, well ... a little nutty.
But it turns out that he was probably right. The reason? The hormone melatonin. Melatonin is a powerful ally in the body's fight against tumor development, and it's usually produced by the body at night. The theory is that night work causes such disruption in your circadian rhythm that it short-circuits melatonin development, opening the door for all manner of nasty, lethal cancers.
There are skeptics who say that the WHO's "probable carcinogen" qualification just means that the night work/cancer link is possible. But if you ask me, this newest study is merely the latest in a long line of respected research that has made the same connection. And to me, this reveals a very strong link. If you're a nine-to-fiver who's about to stop reading because you don't think this has anything to do with you, you may just want to stick around for a few more sentences...
What's true for shift workers who are awake in the middle of the night is equally true for ANYONE whose sleep is continually disrupted - including insomniacs and frequent business travelers. If you've ever said, "This jet lag is killing me," this study proves that you may be more right than you think.
If you ask me, it's more than just a melatonin deficiency at work. If you've ever done any night work, you know how unnatural and disorienting it can be. I certainly don't miss my days as a resident, when midnight-to-eight a.m. shifts were common. With the possible exception of certain teenagers, humans are simply not nocturnal animals. Your body's natural rhythms are delicate and easily disrupted, and this disruption can lead to the breakdown of critical functions. Certain bodily processes like cell division and DNA repair happen at regular times.
And anyone knows that not getting enough sleep makes your immune system vulnerable, making it just as tough for your body to do battle with potentially cancerous cells as with the common cold. Unfortunately, there doesn't seem to be a cure-all for the night workers' potentially deadly predicament. Many of my colleagues say that it is imperative that night workers sleep in a darkened room once they get home from work to help maintain the body's light/dark balance.
I have a suggestion of my own: Don't quit your day job. Turns out it's good for you.