If you don’t get enough ZZZs, it’ll show at work

American adults aren't getting enough sleep - and it's affecting their work.

The National Sleep Foundation has been surveying teens and adults about sleep health and behaviors for more than 20 years. Its 2011 Sleep in American poll found that about two-thirds of Americans didn't get enough sleep throughout the week, and that nearly three-quarters of working Americans admitted that sleepiness had an influence on their work.

The poll noted that adults reported needing about seven and a half hours of sleep to feel rested - yet most averaged less than that.

Dr. Mark Eric Dyken, the director of University of Iowa Hospitals and Clinics Sleep Disorders Center and a professor of neurology, said that the amount of sleep necessary varies per person.

“Most adult human beings need seven to nine hours of sleep,” Dyken said.

Yet “long sleepers” can require up to 10 hours of sleep every night, and it can be hard for them to hold down a job, Dyken said. “Short sleepers,” on the other hand, are a rarity.

“They don't come in to see us (at the Sleep Disorder Center) because they don't have any complaints,” he noted.

There are some 100 different classifications of sleep disorders, including sleep apnea, insomnia and narcolepsy.

A person with sleep apnea experiences repeated stops and starts in breathing of at least 10 seconds and up to a minute.

“The sleep is continually fragmented,” said Tim Rockafellow, technical director at ENT Medical Services Sleep Center in Iowa City.

He has been working in the field of sleep medicine for nearly 20 years.

ENT's physician, Dr. Akshay Mahadevia, conducts about 1,000 overnight sleep studies annually and also sees patients in an outpatient clinic three days per week. A person with any symptoms of sleep disorder should see their primary care physician and ask for a referral to a sleep specialist.

“Typically a sleep partner has complained about symptoms,” Rockafellow said.

That sleep partner might notice loud snoring or pauses in breathing while sleeping or making loud gasping noises, all possible symptoms of sleep apnea. The most common treatment for sleep apnea is a device worn during sleep called a continuous positive airway pressure that forces the airway to stay open.

Many patients report an almost immediate improvement in sleep.

“It's a treatment, not a cure. It's a lifetime thing,” Rockafellow said.

Untreated, sleep apnea can lead to even more serious health consequences. For example, Dyken studies the link between sleep apnea and stroke.

But there are many other side effects of not getting enough sleep. When a person is sleep deprived, he or she can experience symptoms that include impaired judgment, shortness of temper and an increase in motor vehicle accidents, Rockafellow said.

Of those polled for the 2011 Sleep in America report, many reported driving drowsy at least once during the previous month - from 50 percent of 19 to 29 year olds to 28 percent of 46 to 64 year olds. Sleepiness while driving is more of a danger than driving impaired because a person who is impaired by drugs or alcohol can at least attempt to take evasive action, Rockafellow said.

“If you fall asleep, that's it,” Rockafellow said.

Studies show that people who are sleep deprived are more prone to making mistakes.

“This is primarily true of shift workers. We're not nocturnal people,” Rockafellow said.

In addition to how much sleep a person needs, when they need it is also a factor. Most people also fall somewhere on the scale of morningness or eveningness - that is, morning larks or night owls, Dyken said.

An extreme morning lark is not likely to handle shift work - working between the hours of 6 p.m. and 6 a.m. - as well as a night owl. On the other hand, a night owl might not be able to handle a shift that begins at 6 a.m. as well as a morning lark.

Although anyone can be at risk for sleep issues, shift workers are often more at risk. There is even a name for it - shift work sleep disorder.

The National Sleep Foundation noted that the most common complaint for shift worker sleep disorder is excessive sleepiness. Other symptoms include insomnia, reduced performance, difficulties with personal relationships and irritability or depressed mood.

An increased risk for cardiovascular and gastrointestinal diseases also is possible.

Human beings are made to sleep in the dark and our biological clock sets itself by bright light - the sun, Dyken said. Working with others and taking walks during breaks can help shift workers stay awake on the job.

Employees who regularly experience sleepiness at work might be encouraged to keep a diary, Dyken said. And prescribed bright-light therapy properly timed during the sleepy periods can help workers adjust to a new awake cycle.

There are online morningness-eveningness questionnaires that ask about preferred awake and sleeping times, best times during the day for activity and more. Employers who hire for a variety of shifts might include a simple questionnaire during a job application process to better determine which people are best suited for shift work.

A questionnaire for current workers coupled with sleep hygiene wellness information might help employees adapt better sleep habits.

For good sleep hygiene, it's important to keep the same bedtime and awake time throughout the week so that the body isn't constantly trying to adapt its sleep cycle.

“Don't switch on weekends to a daytime shift,” Dyken said.