Shift workers tend to be more sleep-deprived than those who work normal hours for two reasons, said Dr. John Caldwell, chief science officer at Honolulu-based Fatigue Science.
The second reason is that people who work at night and sleep during the day must force their body to do something contrary to their physiological programming.
“The primary driver of your cognitive alertness is how much you’re sleeping every day and what you’re doing to your body clock,” Caldwell said.
Fisher, who has talked to many people who do shift work throughout his career, said common complaints he’s heard include people having difficulty sleeping regularly and not being as alert because they are tired.
“I think it goes against your body’s natural rhythms,” he said.
There are “fairly immediate” cognitive consequences — including deteriorating mental performance, memory lapses and poor reaction time — for people who get six hours a night or less, Caldwell said.
“It’s kind of the lights are on, but nobody’s home phenomenon. You’re sitting there trying to pay attention and something happens that you’re supposed to respond to but it just goes right by you.”
The optimal amount of sleep for adults is seven to nine hours a night and slightly longer for children and teens, Caldwell said.
Many studies have shown that people who regularly cheat themselves out of a proper night’s sleep are at higher risk of developing conditions such as diabetes and cardiovascular disease, Caldwell said.
The tendency to “burn the candle at both ends” cuts across occupations among highly driven individuals, Caldwell said, adding “there’s a myth out there that it’s possible to teach yourself how to sleep less every day.”
While shift work and fatigue go hand in hand by definition, there are things that employers can due to mitigate the effects, Caldwell said.
Mathematical fatigue models can help people design shift rosters in a way that minimizes the strain on workers.
For example, someone whose shift ends at 6 a.m. could reasonably expect to be in bed by 7 a.m. Just after noon, the body will start sending a signal to increase alertness and the person will wind up with about five hours’ sleep, Caldwell said.
If that same worker finished her shift at 9 a.m. and was in bed by 10, she would still wake up around noon but end up with half the amount of sleep, he explained.
There are also things shift workers can do to improve their quality of sleep during the day, Caldwell said. These include making sure the bedroom is completely dark, so much so that you should not be able to see your hand a foot away from your face; using a fan to create soft noise to mask sounds from outside; making sure the bedroom is relatively cool, around 20 C and keeping technology out of the bedroom.
“You don’t want cellphones, computers, anything like that in your bedroom because these are things that engage your mind and get your brain going. Those are not things that promote relaxation.”