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.
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?