Some people bounce out of bed at dawn, ready to take on the day. Others have to hit the snooze button repeatedly before dragging themselves to the coffee pot. Many people are night owls, which is a natural variant of the human circadian rhythm that can be as healthy as any other chronotype. Having an extremely delayed sleep schedule, however, can have extremely negative health effects.

When does a late schedule become unhealthy? How can we ensure that we are getting healthy sleep both in duration and in timing? New research is shedding light on this issue.

What Is Delayed Sleep Phase Syndrome?

While being a night owl is not necessarily a medical problem, some people suffer from a variation of this chronotype that is a true sleep disorder. Delayed sleep phase syndrome, or DSPS, is a sleep disorder in which people are unable to sleep until early morning hours, usually between around 1 and 4 a.m. They then naturally wake later in the morning than people who get to bed at a more normal time.

Certain people appear to be more prone to developing this sleep disorder. Unsurprisingly, so-called “night owls” are at risk, as are those who have an active social life that happens mainly at nights. The problem with this sleep schedule is that most people cannot sleep until late in the day. Most jobs and school schedules require rising early in the morning. In addition, bright morning sunlight may wake people or interfere with their sleep. People with DSPS may compensate by taking naps, sleeping in on weekends and otherwise trying to “catch up” on sleep. While this may relieve fatigue temporarily, it can still leave them with a dysregulated circadian rhythm.

This disorder is believed to cause around 10 percent of chronic insomnia cases. However, you don’t need to have this disease to suffer the effects of a delayed sleep phase. Many people go to sleep and rise later than is optimal because of their schedule and their environment. According to new research, these people may have similar health risks as those with actual delayed sleep phase disorder.

The Effects of a Delayed Sleep Schedule: Diabetes, Depression, and More

Exactly how can going to bed late affect your health? A study in Japan found that people with delayed sleep schedules are more prone to depression. The effect is particularly strong in women, who are almost twice as likely to be depressed when they consistently go to bed extremely late.

In addition, people who go to sleep at late hours may have a higher chance of developing metabolic diseases such as type 2 diabetes, which in turn can cause a great number of complications and even shorten one’s lifespan. A study found that people who went to sleep later in the night were at higher risk of metabolic disease, even when compared to people who are similar in weight and general health.

Are these health effects due to a late bedtime or due to the resulting lack of sleep? Researchers still have not been able to determine the real culprit. However, it is incredibly important for your mental and physical health to get the right duration of sleep (7-9 hours for most people) and also to keep your circadian rhythm as stable as possible.

Is Technology Keeping You Up at Night?

Why have late nights become more of a problem in recent years? Many scientists believe that the problem is multifactorial. Using smartphones and other devices late at night can actually cause delayed sleep behavior, according to a recent study. Light pollution, which is the modern increase in ambient light during supposedly dark hours, also appears to be interfering with falling asleep.

In addition, modern people are busier than ever. Without enough hours in the day to finish one’s work, many are taking time from their sleep to complete tasks. Months and years of this behavior can leave your circadian rhythm off track.

The Challenge of Getting to Sleep Earlier

If you are naturally a night owl, this information can be frustrating. After all, most night owls have truly tried to go to bed earlier and spent long hours staring at the ceiling. There are a few ways to reduce your health risk if your body just prefers late nights. Ideally, people would be able to change their daily schedules so they simply can sleep later. However, this is not possible for many.

Researchers have found that a mixture of bright light and melatonin can help to modify wayward sleep schedules. People who wish to sleep earlier can often change their natural bedtime by shutting down devices, turning off lights, and taking a melatonin supplement. Exposure to bright light in the morning and early afternoon similarly can help your body to naturally wake earlier.

Getting enough sleep at our optimal times can be a challenge. It also appears to be essential for good health. Although we may need to modify our habits and schedules to accommodate a full night, not morning, of sleep, the benefits are undeniable.