Not everyone is a morning person. Some of us work better in the late hours than at the crack of dawn. But most jobs in our society are still geared towards the nine-to-five, forcing those who perform better at night into a schedule that doesn’t always catch them at their best.
“If you are an early bird, work is perfect for you because the world revolves around your schedule,” says Sina Kianersi, an epidemiologist at Harvard Medical School.
But night owls, or those who tend to stay up late and sleep in, might be at greater risk for certain conditions than their early bird counterparts. Scientists have found that forcing night owls into working daylight hours can have a number of negative health impacts.
What's more, new research suggests a preference for burning the midnight oil may be associated with a higher risk of type 2 diabetes — especially when those night owls are forced to conform to conventional office hours.
Night Owls vs Early Birds
"Night owls" and "early birds" are terms commonly used to describe people's natural preferences and tendencies when it comes to their sleep patterns and daily rhythms.
What Is an Early Bird?
If you're a morning person, society likes to portray you as a disciplined go-getter. Early birds, or those who naturally tend to go to bed early and wake up early, often have an easier time adjusting to conventional daytime schedules and working hours.
What Is a Night Owl?
Night owls, meanwhile, tend to naturally stay up late and enjoy sleeping in. As a result, these individuals may also have a harder time staying alert during the day.
Read More: The Strange Sleeping Habits of Homo Sapiens
Are There Any Benefits to Waking Up Early?
That innate inclination to hit the snooze button can come with other downsides, as well. According to a 2019 research review, early birds, or "larks," as they're also known, report higher levels of positive emotions. Beyond that, being a night owl has been associated with metabolic diseases and mental health concerns, including obesity and depression.
Still, being a night owl does come with its own perks. A study published in Personality and Individual Differences found that night owls exhibited more creative thinking — and are able to sustain mental alertness for longer — than early birds.
Read More: Does Snoozing Your Alarm Really Increase Sleepiness?
Do Night Owls Have a Higher Diabetes Risk?
For a study published recently in the Annals of Internal Medicine, Kianersi and his colleagues found that night owls had a 72 percent increased chance of developing diabetes compared to early birds.
What Did the Diabetes Study Examine?
They collected information on the chronotype of 60,000 female nurses from 2009 to 2017. All were free of diabetes, cancer, or cardiovascular diseases at the beginning of the study period.
What Traits Did the Diabetes Study Observe?
Throughout the study period, the researchers regularly collected information on the body mass index, lifestyle, sleep patterns, and exercise level, as well as the smoking and alcohol consumption of the nurses. The scientists also examined the nurses' medical reports for diabetes.
Were There Any Outliers to the Study?
But this increased risk wasn’t there with all night owls. Night nurses — those night owls who typically worked late hours at their clinics or hospitals — were just as likely to develop diabetes as early birds, working early hours. The discrepancy was heaviest among night owls forced to work earlier hours. “The association between being a night owl and having an increased risk of diabetes was only there for those who reported no night shift work,” Kianersi says.
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Why Are Night Owls More Vulnerable to Diabetes?
Furthermore, the increased risk of diabetes was a lot lower for daytime-working night owls who led a healthy lifestyle. These night owls only had a 19 percent increased risk of diabetes compared to early birds, the researchers found.
Can You Decrease Your Risk for Diabetes?
“That implies that night owls, by engaging in healthy lifestyle, can substantially decrease their diabetes risk,” Kianersi says. However, the remaining discrepancy between otherwise healthy night owls reveals that lifestyle choices may not be the only factor when it comes to determining the risk of diabetes.
While the reasons behind it aren't completely clear, Kianersi says that genetic factors may play a role in this remaining increased risk. What seems clearer is that night owls are more likely to remain diabetes-free if they find jobs or shifts that better suit their sleep chronotype.
Read More: What Science Says About Using Sleep Medications
What Are the Results of the Diabetes Sleep Study?
Night owls accounted for about 11 percent of the 60,000 nurses examined that Kianersi and his colleagues tracked in this study — about 7,000 people. This roughly matches other studies that have looked at society in general, Kianersi says.
Kianersi also cautions that these results were only drawn from females, who were predominantly white from the 45 to 62 age group. Night owls from other ethnicities, sex, and age groups may have lower or higher diabetes rates if they are forced to work outside of their natural sleep chronotype.
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Can Night Owls Become Early Birds?
Our internal clock, or circadian rhythm, is responsible for a number of things other than regulating our sleep-wake cycle. It can dictate body temperature, heart function, hormone release, and other parts of our physiology. For example, our internal clock will release insulin when we are supposed to wake up to help us digest the first meal of the day.
How Does Circadian Rhythm Affect Sleep?
Researchers have found that our circadian rhythms are deeply engrained in our basic biology. Still, some research suggests that it is possible to shift our own sleep patterns, helping even lifelong night owls (perhaps begrudgingly) become early birds.
How Does Circadian Rhythm Affect Stress?
A 2020 study found that night owls reported lower levels of depression and stress after adhering to a stricter schedule, including waking up three hours earlier and exposing themselves to direct sunlight as soon as they could.
Read More: How Your Circadian Rhythms Control Your Every Waking — and Sleeping — Moment
How Many People In the U.S. Have Diabetes?
Meanwhile, the U.S. Centers for Disease Control and Prevention reports that 37.3 million Americans have diabetes — 8.8 million of which are undiagnosed. The fact that so many people might be forced to conform to a schedule that doesn’t suit them has implications for public health in general.
“If our internal body clock is not synced with the world around us, then it can cause problems for us,” Kianersi adds.
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