Shift Work and Sleep: Always Incompatible?

The worst insomnia I ever had came when I was living in Mexico. I worked a split shift then, teaching English classes from 7 to 10 in the morning and then from 7 to 9 at night. This schedule might not sound difficult: a few hours’ work at both ends of the day, with the rest of the day free for sightseeing, napping, or doing whatever I pleased.

It was tough for me.

Insomnia and a poorer quality of life may result from working irregular hoursThe worst insomnia I ever had came when I was living in Mexico. I worked a split shift then, teaching English classes from 7 to 10 in the morning and then from 7 to 9 at night. This schedule might not sound difficult: a few hours’ work at both ends of the day, with the rest of the day free for sightseeing, napping, or doing whatever I pleased.

It was tough for me.

I’m a morning person, so getting up at 5:30 or 6 is normal. But gearing up for the evening classes took effort. Then I was wired after class. I had to spend at least a few hours winding down, and by then it was after midnight. The thought of having to throw my clothes on again at 6 made me anxious: what if I couldn’t sleep?

Working this split shift was a set-up for insomnia. I tossed and turned in bed, and on too many days I woke up to the sound of the alarm clock feeling achy and spent. It was all I could do to show up for my early class on time.

Shift Work and Chronotype

I put up with this schedule for one semester, but for millions of Americans, shift work is an ongoing part of life. Whether it’s a job in a hospital or in IT, in manufacturing or in the transportation industry, it probably involves working nights, evenings, or early mornings; or on rotating shifts or shifts other than the standard 8 to 5.

Shift work may keep you solvent, but it can also have negative effects on sleep and health. It disrupts the functioning of the body clock, altering physiologic processes and the activity of genes.

A new study in Current Biology suggests that adjusting work time to correspond more closely with an employee’s natural cycle of activity and rest may alleviate some of the harms associated with shift work. To conduct their research, investigators took a group of factory workers and divided them by chronotype—their preferred hours of sleep and activity:

  • Early birds (who preferred to go to bed and get up early)
  • Intermediate types
  • Night owls (who preferred to go to bed and get up late)

Then, to promote better sleep and reduce the mismatch between preferred wake and work times, they exempted the early birds from working their most challenging shift: the night shift (10 p.m. to 6 a.m.). Likewise, the night owls were exempted from working their most challenging shift: the morning shift (6 a.m. to 2 p.m.). The intermediate group served as control subjects, continuing to work morning, evening, and night shifts.

More Sleep and Satisfaction

The results confirmed many of the researchers’ predictions. Exempted from working their most challenging shifts,

  • Both early birds and night owls slept up to 30 minutes longer on workdays.
  • Both early birds and owls reported better sleep quality and a greater sense of well-being on workdays.
  • Early birds’ and owls’ sleep time on weekends more closely matched their sleep time on workdays (a consistent sleep schedule on weekends helps keep the body’s circadian system in sync).
  • Early birds reported increased satisfaction with their leisure time.

The researchers conclude by stating what many shift workers must already suspect: working more in accordance with natural circadian preferences might improve shift workers’ sleep, quality of life, health, and even productivity.

Whether many industries would or could take chronotype into account when making work assignments is an open question. My solution to the shift work problem in Mexico was to take a job with more regular hours.

If you’ve had experience working irregular hours, how has it affected your sleep and quality of life?

 

Sleep Well Despite Poor Work Conditions

Stressors at work— demanding bosses, looming deadlines, performance reviews, and the like—can fuel insomnia. But low light and the timing of work can also affect sleep. Lack of exposure to sunlight on the job and night or shift work may reduce total sleep time and deprive you of energy in your waking hours.

But you may be able to manage these less-than-optimal work conditions in ways that improve both your sleep and your stamina.

working without natural light has a negative effect on sleep and staminaStressors at work— demanding bosses, looming deadlines, performance reviews, and the like—can fuel insomnia. But low light and the timing of work can also affect sleep. Lack of exposure to sunlight on the job and night or shift work may reduce total sleep time and deprive you of energy in your waking hours.

But you may be able to manage these less-than-optimal work conditions in ways that improve both your sleep and your stamina.

Working without Natural Light

Working without the benefit of sunlight during the daytime has a surprisingly negative effect on sleep, a new study in the Journal of Clinical Sleep Medicine shows. The goal of the study was to compare the vitality and sleep of employees that worked in windowless cubicles to those of subjects whose workstations were exposed to natural light.

Not only did the 22 workers in the windowless cubicles report less activity during the daytime and poorer quality sleep. On average, they also got 46 minutes less sleep than the 27 employees who worked near windows.

Out of Sync

The timing of your workday can also interfere with your sleep. Nearly 15 million full-time American workers labor on schedules that involve night, rotating or irregular shifts, which necessitates the resetting of the body clock.

Having to work when you’d normally be asleep and to sleep when you’d normally be awake causes changes in the activity of genes, a study recently published in the journal Proceedings of the National Academy of Sciences shows. Genes control the production of proteins, and to function optimally, protein production needs to coordinate with the natural cycle of activity and rest.

When the body clock is reset, as occurs in people who do night and shift work, the number of genes synched up to the body’s natural circadian rhythms falls rather dramatically, pushing digestive and other physiologic processes out of whack. Ten percent of shift workers are regularly diagnosed with “Shift Work Sleep Disorder”—they feel sleepy on the job and have insomnia when it’s time to sleep.

Night owls may choose to work the night shift and, given their delayed circadian rhythms, this schedule suits them to a “T.” Others fare poorly. The years when I worked a split shift were the years when my insomnia was at its worst.

What’s a Worker to Do?

If low light is a problem at work,

  • Invest in a light box and use it (for tips on how to use a light box, see my blog on winter insomnia)
  • Go outside or to sunlit parts of the building during breaks.
  • If you do work near windows, keep the blinds open and, if necessary, use anti-glare shades for computer screens.

If the timing of your workday is a problem,

  • Aim for consistency in your sleep schedule. It may be tempting to alter your sleep schedule on weekends to maximize time with family and friends. But having to readjust to your weekday schedule on Monday may leave you struggling to stay alert at work and tossing and turning in bed.
  • Manipulate your exposure to light. Bright light in the work environment will help to keep you alert and on your toes. But exposure to sunlight on your way home from work will tend to delay sleep further. If your goal is to get to sleep immediately after work, wear dark glasses on the way home.
  • Make judicious use of caffeine. Drinking coffee at the beginning of your shift should not interfere with getting to sleep when you get home. But the caffeine-sensitive will want to avoid caffeine later in the work shift. If sleepiness becomes a problem, the better strategy is to get up and move around.