Because our body clocks, which control our sleep schedules, are sensitive to light, things like how much sunlight we’re exposed to throughout the day and what types of light we’re exposed to at night affect our sleep schedules.
Additionally, things like traveling across time zones or staying up a lot later than usual can throw off sleep patterns because we’re asking our bodies to sleep at different times than our bodies’ internal clocks are telling us to sleep.
Similarly, people who do rotating shift work, such as overnight workers or truck drivers — who aren’t able to stick to a consistent sleep schedule — tend to have difficulty with sleep because their body clocks run on a different schedule than they’re allowing their bodies to follow.
It’s problematic, not only because having a misaligned body clock and sleep schedule on a day-to-day basis can result in poor sleep quality (and you not getting the sleep you need), but over time, that misalignment has been linked to several chronic health problems, such as sleep disorders, obesity, diabetes, depression, bipolar disorder, and seasonal affective disorder, among others.
Another sneaky sleep disrupter is the idea of “social jetlag,” in which people are spending more time online and on their phones at night — and even going to bed later without always realizing it.
Having a severely misaligned body clock and sleep schedule is itself considered a sleep disorder. About 1 percent of adults have advanced sleep phase disorder, meaning they go to bed early, from 6 p.m. to 9 p.m., and wake up early, between 1 a.m. and 5 a.m.
Others, especially younger people, may experience the opposite: delayed sleep phase syndrome (DSPS), or going to bed extremely late and waking up late. It’s estimated to affect as many as 15 percent of teenagers.
“DSPS is a circadian rhythm disorder associated with an inability to fall asleep at the individual’s desired time [typically several hours later] and an inability to wake up at the desired time,” says Dr. Zozula. “Due to the individual’s daytime obligations, a person with DSPS may be forced to wake up earlier and go against their natural circadian tendency.” This can lead to chronic sleep deprivation, poor performance, and depression.
