NARRATOR : Night shift police officers Like Doug Dunwoody here are fighting something else. They're fighting Mother Nature. Namely they're fighting their biological clock. So what exactly is the night shift? What are the hours?
DOUG DUNWOODY (Late-Shift Police Officer) : We start at 11:30 and we end at 7:30 in the morning.
NARRATOR : It's a growing phenomenon impacting virtually every industry. One in five Americans now work non-traditional hours.
MARTIN MOORE-EDE : The world works 24 seven. Businesses run 24 seven. We manufacture 24 seven. We have telecommunications and satellites and the internet and computer systems all operating around the clock.
NARRATOR : Our internal clock that tells us when to sleep is set by light. No matter what we do, our circadian rhythms will never adjust to staying up all night. The result. Shift workers are perpetually sleep deprived.
DOUG DUNWOODY : When I first started the night shift it was difficult to. To go to bed at seven o'clock in the morning.
ANDY COSTA (Shiftwork Supervisor) : I do everything from putting cardboard in the windows to turning an air conditioner on or things like that so you can sleep.
MARTIN MOORE-EDE : That is something that our human bodies just weren't designed to do.
NARRATOR : Working at night takes its toll on the immune system. It may lead to a decrease in the so-called natural killer cells in our blood. These cells play an important roll in the fight against infection.
RON TYLER (Shift Worker) : Shift work is the hardest work that there is.
NARRATOR : Studies show staying awake too long increases blood pressure. Night time work raises the risk of heart disease by as much as 50 percent.
ANDY COSTA : You know you try to. Try to take your body out of its natural rhythm and then you end up screwing things up even worse.
NARRATOR : Industrial accidents resulting from exhaustion cost the U.S. 77 billion dollars a year.
MARTIN MOORE-EDE : The most notable major industrial accidents of our time: Exxon Valdez, Bopal, Chernobyl, Three Mile Island. All occurred on the night shift.
ANDY COSTA : A guy who's been awake for a certain amount of hours is just like somebody who's legally drunk.
NARRATOR : In fact a recent study found the impairment of hand eye coordination after staying up 24 hours is equivalent to a point one percent blood alcohol level. Enough to be considered drunk in most states.
KAT CARNEY : Has this had been your. Your shift for ten years straight?
DOUG DUNWOODY : This has been my shift for ten years. Definitely this is. This is all I know right now.
KAT CARNEY : Wow. That's a heck of a schedule.
DOUG DUNWOODY : It is.
KAT CARNEY : I'm complaining about this one night shift I'm working. If you're a shift worker here's some tips to maximize your alertness keep you safe and help get you to sleep after a long night's work.
NARRATOR : Work with a buddy who can help keep you alert. Take care of dangerous tasks early in your shift when you are most alert. To avoid drowsy driving. Take public transportation or have someone pick you up at work. Wear dark glasses on your way home so the sunlight doesn't trigger your body to stay awake. And lastly. Make sleep a priority. Seek absolute darkness and eliminate disturbances at home.