The Perks and Perils of Split Sleep Schedules for Shift Workers

One of the most difficult aspects of shift work is figuring out when to sleep. You may get right to sleep after work but wake up earlier than intended, alert and unable to return to sleep. It may feel fine in the afternoon, but by the time the next shift starts exhaustion sets in.

Some shift workers adapt by splitting their sleep into two shorter periods each day. It works like this: sleep 4 to 5 hours in the morning, wake up in the early afternoon, and then take a long nap 2 to 3 hours before work.

Those with split sleep schedules say it allows for more flexibility to participate in daytime and early evening activities including parenting, socializing and running errands.

A limited body of research topic suggests a split sleep schedule is no different than sleeping exclusively during the daytime. Alertness levels are about the same in both conditions. It’s up to shift workers to decide what strategy is the best fit to get the maximum amount of sleep.

A 1998 study used computer modeling to test different sleep approaches for shift workers, including split sleep schedules. Results show a long late nap may increase alertness and minimize risk of injury or mistakes when the nap is taken around 1 a.m. The unfortunate reality is most overnight shift workers don’t have that luxury.

The authors determined the next best time for a nap is leading up to the start of work. This may help but it’s likely you will find yourself struggling to stay awake for most of your shift, especially between 2 a.m. and 6 a.m.

The study included a model for sleeping exclusively during the daytime. The results were nearly identical; sleeping a full 7.5 consecutive hours in the daytime leads to the same overnight alertness levels, however reduced, as napping before work.

A NASA funded experiment by researchers at the University of Pennsylvania Medical School came up with the same conclusion. The study looked at whether astronauts and mission control personnel could perform sufficiently under nontraditional sleep schedules, including split sleep.

Researchers monitored 90 subjects in a controlled laboratory with no external time cues for 14 consecutive days. Participants were assigned to one of 18 strict sleep conditions that included a mix of split sleep schedules and full daytime sleep schedules. The control group slept at night for about eight hours. The participants were given a series of alertness tests every two hours they were awake.

There was no measurable difference between split sleep schedules and daytime sleep, as long as the total sleep length was sufficient. The authors concluded split schedules have no negative impact and may allow more lifestyle flexibility for civilian shift workers.

Both approaches have their downsides. Staying asleep through the afternoon may be a challenge, especially during the summertime. Taking a late nap may make it difficult to fall asleep after work. Insomnia is a common complaint for all types of shift workers.

There are several other things you can do to make the shift work experience more tolerable. When used properly caffeine can be a boon for shift workers. A recent study found drinking coffee at the beginning of the shift can cut down on workplace mistakes.

Bright light therapy can also help increase alertness. The Sleep Education blog recommends using a light box for 15 minute increments at your workstation during the first half of your shift. Be careful not use a light box towards the end of your shift. Exposure to bright light close to bedtime may make it difficult to sleep.

Some shift workers describe feeling a surge of energy towards the end of shifts, especially after dawn. It’s important to avoid sunlight before trying to sleep. We suggest wearing dark sunglasses on the commute home from work. Also try to make your bedroom as dark as possible, by using blackout curtains.

High temperatures and daytime noise are two other common environmental sleep disruptions for shift workers. The Sleep Education blog suggests running the air conditioning along with a loud fan or noise machine.

Slightly adjusting your sleep schedule on days off may also help your body recover from shift work related sleep deprivation.

Are the best and brightest natural night owls?

Our society seems to celebrate the ambition of early risers. We tend to admire the person who’s out on a seven mile jog at the crack of dawn or the employee who’s firmly planted at their desk long before everyone else arrives.

The night owl, who sleeps through most of the morning, is viewed as lazy or irresponsible at best, drunks or criminals at worst.

Do we have it all wrong? Evolutionary psychologist Satoshi Kanazawa poses that question in the latest entry in his blog The Scientific Fundamentalist.

He hypothesized the most intelligent American children grow up to sleep in later their peers. The author looked at the possible relationship between early childhood IQ scores and reported bedtimes in early adulthood.

Kanazawa classified children into five categories according to their IQ scores. Children with IQ less than 75 were considered very dull, above 125 were called very bright. Those in the middle of the bell curve, with a score around 100 were considered average.

You can see in the charts below, the higher the childhood IQ scores the more likely the subjects were to stay up later in early adulthood.





While the data suggests the smartest people turn out to be night owls and the least intelligent end up as larks, there might be more to this relationship than the author lets on. In his entry he fails to define early adulthood. If this includes people around the ages of 18-25 there may be some lifestyle factors at play.

College students are notorious for their nocturnal tendencies. Most Americans of above average intelligence pursue some form of higher education. Many of the most gifted go on to get Master’s degrees or PhD’s, extending that lifestyle by 2-6 years.

Those that choose to go straight into the workforce after high school don’t have the luxury of making their own schedule and sleeping in like college students. They jump right into working the typical 8-5, or even early bird hours, in the case of some blue collar jobs like manufacturing.

Regardless of if the hypothesis is true both chronotypes still come with downsides. Evening-types have a higher risk of severe depression symptoms. Larks may never reach a level of maximum performance during the day.

Contrary to traditional wisdom, morning types were found to be no healthier, wealthier, or wiser than night owls.

It’s best to follow your instincts when it comes to your sleep schedule. Trying to switch from night owl to lark may end up cutting into length of sleep, ultimately doing more harm than good.

College Students & Parents: Sleeping in Different Time Zones

Earlier this week Michelle Slatalla wrote in the New York Times about how her sleep was disrupted when her two older daughters came home from college for winter break.

The nocturnal habits that her daughters developed as teens had escalated. At 3 a.m. they texted, made phone calls, played video games and watched TV as if it were daytime.

“It seems as if my husband and I live in a completely different time zone from our children,” Slatalla lamented.

AASM secretary/treasurer Dr. Nancy Collop told Slatalla that these habits tend to reinforce a late-night schedule.

“There are lots of environmental issues that play a role in altering people’s sleep patterns,” said Collop. “The most obvious would be the computer.”

Light is an important timing cue for the brain. It is a signal that tells the brain it is time to be alert. Staring at a brightly lit computer screen at night sends a stimulating signal to the brain.

So will Slatalla ever see her children again?

Sleep researcher Mary Carskadon, PhD, told her not to worry. Their brains are still developing. So their sleep patterns are likely to shift as they get older.

“The brain tends to correct itself,” said Carskadon.

Image by nickestamp

A Sleep Schedule that Works for the Night Shift

A series of studies have found that a “compromise” sleep schedule is effective for people who work night shifts. The results of the latest study were published in the Nov. 1 issue of the journal Sleep.

The sleep schedule improves alertness during the night shift and daytime sleep after the shift. But it also provides a “compromise” that helps night-shift workers on days off.

It enables them to get the sleep they need; but it also gives them more free time during the day.

“We think that most real shift workers want to be awake on their days off,” lead author Mark Smith, PhD, previously told the AASM.

Here’s the “compromise” sleep schedule for night-shift workers:

• Sleep from 8:30 a.m. to 3:30 p.m. after regular night shifts.


• Sleep from 8:30 a.m. to 1:30 p.m. after the last night shift before a weekend off.


• Sleep from 3 a.m. to noon on days off.

The studies also used three light-related strategies to increase the effectiveness of this schedule. Light is an important timing cue that helps your body regulate sleep and alertness.

First, workers received bright light therapy during simulated 11 p.m. to 7 a.m. night shifts. Light boxes were used during four, 15-minute sessions.

The first session began at 12:45 a.m. These sessions were repeated hourly, with the final session ending at 4 a.m.

Second, workers had to go outside within the first two hours after waking up. They needed to get at least 15 minutes of exposure to daylight.

Third, the workers wore dark sunglasses at all times when outside during the day. This was most important when traveling home after a night shift.

The current study found that workers had improved mood, fatigue and performance during night shifts when following the compromise sleep schedule. These levels were similar to daytime measurements obtained during “9 to 5” work days.

The authors caution that the participants were not real shift workers; they were young volunteers. The “night shifts” were conducted in a laboratory. So the compromise sleep schedule still needs to be tested in real night-shift workers.

Learn about shift work sleep disorder on SleepEducation.com.

Image by GaijinSeb

Lying Awake & Sleeping in Two Shifts

Waking up in the middle of the night and being unable to return to sleep is one sign of insomnia. But a recent story on NPR’s “Morning Edition” suggests that this wasn’t always the case.



A period of wakefulness in the middle of the night used to be the norm. At that time there were no lights to turn on at night. When it got dark outside, it was just as dark inside.

A winter night can bring 14 hours of solid darkness. That’s a long time to spend in bed.

So what would happen? There are reports that people would sleep in two shifts through the night. In between, they would lie awake for a period of time.

But this wasn’t a frustrating, anxious, tossing and turning kind of awake. It was more of a relaxing, late-night pause before the early-morning sleep shift.

The story even cites a 1993 study that simulated this long, dark winter night. Fifteen volunteers spent 14 hours in bed in a sleep lab. The lights were turned out from 6 p.m. to 8 a.m.

Sure enough, they slept in two shifts. In the middle was a period of wakefulness lasting a few hours.

"You might think that lying awake for two hours would be a kind of torture," study author Thomas Wehr told NPR. "But it wasn't at all."

This news might be a comfort for older adults who tend to have more fragmented sleep. They may have a more flexible schedule that allows them to spend a long winter’s night in bed.

But 14 hours in bed? That’s close to impossible for most people today.

Yet you can implement a less extreme version of the two-shift sleep method. One proponent of the split-night sleep schedule is Dan Henning, who is 67 years old. He is the offensive coordinator for the Miami Dolphins.

The Palm Beach Post reports that he goes to bed by 9 p.m. Around 2 a.m. he likes to wake up for about 45 minutes of “personal time.” Then he returns to sleep.

So in a perfect world, what would be your sleep schedule?

Physical Activity & Improved Sleep in Children

Do children really sleep better if they’ve been more active during the day? A new study from New Zealand may confirm what parents have long suspected.

The study involved 519 children who were 7 years old. Their activity was measured for 24 hours by an actigraph that they wore on their waist.

Results show that children who were more active during the day fell asleep faster at night. As their mean daytime “activity count” increased, their time to fall asleep decreased.

Overall, the children took 26 minutes to fall asleep on average. Each hour of daytime inactivity increased the time it took children to fall asleep by 3.1 minutes.

Children who fell asleep faster also slept longer, reports the BMJ Group. Every 11-minute drop in the time it took to fall asleep was associated with an extra hour of total sleep time.

In the journal Sleep in 2008, the same research team published an early analysis of the same sample of 7-year-old children. The study found that their average sleep time was about 10 hours.

Their average bedtime was 8:15 p.m.; their average rise time was 7:07 a.m. Children who went to bed after 9 p.m. slept about 41 minutes less than other children.

On weekend nights the children slept about 27 minutes less than on school nights; although they went to bed about 30 minutes later on weekends, their morning rise time was only slightly later.

There also was a seasonal effect, with children getting the least sleep in summer. They slept about 40 minutes longer in winter, 30 minutes longer in fall and 15 minutes longer in spring.

The study also found that children who slept less than nine hours at night were three times more likely to be overweight or obese. The increased risk remained even after controlling for factors such as TV watching and sedentary activity.

The AASM recommends that school-aged children get about 10 to 11 hours of sleep each night. Learn more about sleep and children on SleepEducation.com.

Image by Elke Noda

Sleep & Jet Lag on Day 2 of “March Madness”

How did yesterday’s jet lag-challenged teams fare on the first day of the NCAA basketball tournament?

BYU came out flat, fell behind and never caught up to Texas A&M. Cal State Northridge was the opposite. They started strong but faded late in a loss to Memphis.

As for UCLA, they’re probably relieved to have escaped with a one-point win. After crossing three time zones to play a late game, they’ll surely get some rest today on their day off.

Which teams are most likely to come out sluggish on day two of the tournament?

Utah St. gets to stay “home” in the Mountain time zone to play Marquette in Boise, Idaho. But it will be an early morning for the Aggies.

The 12:30 p.m. EDT tip-off means that the game will start at 10:30 a.m. locally. It will feel like 11:30 a.m. for sixth-seeded Marquette, which will travel from Milwaukee in the Central time zone.

Stephen F. Austin plays in the earliest game against third-seeded Syracuse. The 12:15 p.m. EDT start in Miami, Fla., will feel like 11:15 in the morning for the Lumberjacks from the state of Texas.

Oklahoma St. faces a similar challenge. The 12:25 EDT tip-off in Dayton, Ohio, will feel like 11:25 a.m. for the eighth-seeded Cowboys. Knoxville, Tenn., is in the part of the state that is in the Eastern time zone. So there will be no time change for the Volunteers.

Travelling east may be a challenge for Arizona St. Arizona does not recognize daylight saving time. So the state is currently three hours behind Eastern Daylight Time.

Temple will try to upset the sixth-seeded Sun Devils at 2:45 EDT in Miami. It will feel like an 11:45 a.m. start for Arizona St.

Cornell will take a long flight from Ithaca, N.Y., to Boise to play third-seeded Missouri. The 3 p.m. EDT start time won’t be a problem. But the long flight could take a toll on the players.

Fifth-seeded Florida St. also had to make the long trip to Boise to play Wisconsin. In addition to the flight, the Seminoles will have to deal with an unusual 9:55 p.m. EDT tip-off.

In the end, sleep can be a challenge for players on every team. The excitement and pressure of the tournament can lead to sleepless nights. The Herald Journal described how the Utah St. players struggled to sleep during their conference tournament.

And players aren’t the only ones fighting sleep loss. Fans on the East Coast have to stay up late to watch all of the 10 p.m. games.

So try to get some sleep even as you enjoy the madness.

Sleep, Jet Lag and “March Madness”

The NCAA basketball tournament tips off today at 12:20 p.m. EDT. Did you finish your bracket yet?

President Obama completed his bracket early. Surprisingly, he was extremely “conservative” with his picks.

His Elite Eight includes all four of the number-one seeds and three of the number-two seeds. His only sleeper? Third-seeded Syracuse over second-seeded Oklahoma.

If you’re still finalizing your bracket, one thing to keep in mind is jet lag. Some teams have to travel a long way to play their first game.

One example is UCLA. The Bruins have to cross three time zones to play upset-minded Virginia Commonwealth in Philadelphia, Pa., tonight.

The good news for UCLA is that the game won’t start until almost 10 p.m. EDT. They’ll be playing when their body clocks are set at a West-Coast time of 7 p.m. So it will feel like a normal tip-off time for the Bruins.

It’s the earlier, 12:30 p.m. EDT start times that can be more difficult for some players. Cal State Northridge and BYU both must cross two time zones to play opening-round games today. It will feel like a 10:30 a.m. start for the players on both teams.

Cal State Northridge plays Memphis in Kansas City, Mo. BYU plays Texas A&M in Philadelphia.

But can sleep really have an effect on a basketball game?

Just ask Cheri Mah of the Stanford Sleep Disorders Clinic and Research Laboratory. She has studied how sleep affects players on many of the Stanford sports teams.

One study involved six players on the men’s basketball team. Performance measures such as sprint times and free-throw shooting improved after extra sleep. So did ratings of mood and alertness.

“Sleep is a significant factor in achieving peak athletic performance,” said Mah. “Athletes across all sports can greatly benefit from extra sleep and gain the additional competitive edge to perform at their highest level.”

So sleep may be one factor that adds to the madness of this year’s tournament.

White House Photo, 3/17/09, Pete Souza

Sleeping on the Job Proves Costly

ABC News reports that a nuclear power plant was fined $65,000 because security workers were caught sleeping on the job.

Video images of sleeping guards were recorded by a fellow guard at different times of day. A federal investigator also discovered a guard sleeping at his post.

The incidents occurred at the Peach Bottom Nuclear Plant just outside of Philadelphia. The guards are responsible for protecting the plant from a terrorist attack.

Falling asleep on the job is a clear sign of severe sleep deprivation. This is common when security guards work more than one job.

Excessive daytime sleepiness can be a sign of another sleep disorder. These include obstructive sleep apnea, restless legs syndrome and narcolepsy.

Sleepiness on the job also is a common sign of shift work disorder. The problem can be severe for people who work rotating shifts or night shifts. This forces them to be alert at a time when the body is normally asleep.

Then they have to try to sleep during the day. Daytime distractions can make this difficult. In a recent study of 163 nurses, more than 70 percent of the nurses report that they are unable to get enough sleep.

A recent study in the journal Sleep reports that night-shift workers can benefit from a realistic but strict sleep schedule. It helps them remain alert during the night shift and allows them to stay awake during the day on days off.

Subjects slept in dark bedrooms at scheduled times: 8:30 a.m. to 3:30 p.m. after the first two night shifts. From 8:30 a.m. to 1:30 p.m. after the third night shift. From 3 a.m. to 12 p.m. on the two weekend days off. And again from 8:30 a.m. to 3:30 p.m. after the final four night shifts.

They also were exposed to five, 15-minute sessions of bright light therapy each night shift. Within two hours after waking up, they went outside for at least 15 minutes of natural light exposure. But they wore dark sunglasses whenever they were outside.

The schedule enabled them to perform well at work and sleep well at home. Contact an AASM-accredited sleep center if you are sleeping on the job or struggling with a shift-work schedule.

The Phelps Plan: Get on a Schedule

Five months after the Beijing Olympics, Michael Phelps is back on a schedule. In the pool. In the weight room. And in bed by 10:30 p.m.

“I can get to sleep earlier,” Phelps told the Associated Press. “I have no problem falling asleep now. I was completely worn out my first day back. After two hours or so of working out, I was absolutely dead. I had no problems falling asleep at 10 or 10:30 that night. It feels good to add some scheduling back to my life.”

His experience highlights one key for curing sleepless nights: You need to get on a schedule.

Your body functions best when you keep to a regular schedule. This includes going to bed and waking up at the same times every day. Yes, even on weekends.

Regular meal times should be another part of your schedule. You also should try to get some exercise at a scheduled time. It doesn’t have to be a Phelpsian workout. Even some light exercise will help.

These routine events act as “timing cues” for your body. They are signals that let your body know what time of day it is.

Another important timing cue is daylight. Letting your eyes see the bright morning light alerts your body that it is time to get moving. In contrast, the dim evening light is a signal that it is time to wind down.

Following a daily routine is one way to help you fall asleep easier at night.