Mar 30 2018

Social Jet Lag

Sleep is critical for optimum health and performance, but is often underappreciated by the general public. For example, I see many patients with chronic symptoms that are either caused by or greatly exacerbated by poor sleep, but didn’t make the connection to their chronic insomnia.

Not only is adequate quality sleep necessary, people have different daily (“circadian”) rhythms – some people are most alert in the morning, others mid-day, and still others in the evening. Further, this does not seem to be due entirely to habits, and therefore we cannot just tell night owls to go to bed earlier. They are not in control of their biological rhythm.

The sleep rhythm is affected by light levels and seasonal differences, so there is some room for tweaking the environment to improve sleep overall and adjust the daily cycle. Bright lights and close-up electronic devices are terrible for sleep in the late evening. If someone is having trouble getting to sleep, having 2 hours or so without electronic devices prior to bed time is a good idea.  But there are limits here as well Рnight owls will still be night owls.

A recent study looks at the effect of circadian rhythm on school performance. The hypothesis was that a mismatch between a student’s internal schedule and their forced school schedule would affect performance.

Interestingly, the study benefits from our new era of big data. The researchers used the login times for the school internet to track 14,894 Northeastern Illinois University (NEIU) students over two years. This created a real-world picture of when these students were active. They then divided the students into three groups, for those who were most active (on days when they did not have classes) in the morning, afternoon, or evening.

They then compared their off-day activity with their class schedules. As predicted, those students who had a mismatch between their preferred schedule and their class schedule had lower grades.

“We found that the majority of students were being jet-lagged by their class times, which correlated very strongly with decreased academic performance,” said study co-lead author Benjamin Smarr.

Of the students tracked, 50% had classes scheduled earlier than their peak time, and 10% later. They called this mismatch “social jet lag”. There also does seem to be a cultural bias favoring the early bird, and shaming late risers, as if there is a moral dimension to our sleep schedules. School schedules overall favor early birds.

This is not only an issue for college, but for middle and high school also. The evidence is fairly compelling, leading the American Academy of Pediatrics to recommend that schools start at 8:30 or later. The average start time for high school classes in 8:00, with many starting earlier. This may seem like a small difference, but an extra hour of sleep can have a measurable effect on performance.

In college students have more flexibility in choosing their classes, but limited choices are still an issue. If you need an 8am class for your major, and you are a night own, you’re screwed.

Essentially, over the last 20 years, the research has moved consistently in the direction of indicating that people do have an inherent circadian rhythm, starting classes too early has a negative effect on both health and school performance, and night owls are particularly hard hit by being forced into early class times.

We need to get over our cultural bias toward early risers, and simply view this as a health issue. People should be aware of those behaviors considered to be good sleep hygiene, and people are responsible for their own sleep-related behaviors. But people should not be blamed for their biology, and a reasonable accommodation can easily be made to better align class times with our biology. Later start times for middle and high school are a no-brainer. More flexible schedules for college students might be a challenge but is certainly doable.

In fact, more flexible work schedules are also a good idea. Some companies do have flexible start times, mainly with the idea that some parents may get a late start because they have to get their children off to school, or want to be home a little early for their kids. But this flexible schedule can also be used to accommodate different sleep rhythms.

If you are a night owl, getting to work at 10am and working until 6pm may actually improve your performance at work. This could be cost effective for some companies, justifying the added cost of keeping the light on for an extra hour.

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