What Makes Someone a Night Owl Vs. an Early Bird?

Ever wonder why some people are up before dawn ready to start their day and others aren’t ready to call it a night until the wee hours? While lifestyle may impact the hours we sleep, there’s also a natural rhythm that we’re driven by.

“The same way the heart has a pacemaker, the sleep process has a pacemaker — your sleep rhythm,” says Dr. Ana C. Krieger, director of the Center for Sleep Medicine at NewYork-Presbyterian/Weill Cornell Medical Center and Weill Cornell Medicine. “Being aware of your chronotype is one key to optimizing sleep and a healthier lifestyle. It’s important to understand your sleep cycle preference so you can adjust your activities to better match your chronotype and improve your sleep.”

Health Matters spoke with Dr. Krieger to learn how a personal sleep cycle works and why it’s important to protect and improve the quality of your sleep.

Why are some people early birds while others are night owls?

Dr. Krieger: Chronotypes, like being an early bird or a night owl, relate to our genetic inclination to sleep at a certain time of the day. We have genes that regulate our sleep cycles and release melatonin at a particular time to help prepare for sleep. This is a complex process that also involves the synchronization of several metabolic processes and hormones, including melatonin, growth hormones, and cortisol.

For night owls, all of that happens later. So, when people force themselves to go to bed early, they might be unable to sleep simply because the body isn’t ready.

People who regularly go to sleep before 9 p.m. and wake up very early have what we call advanced sleep phase. Others who go to bed after 2 a.m. and sleep in late, have what’s called delayed sleep phase. Only a small percentage of the population is found to have those extreme features: around 4% have delayed sleep phase and 2% or less have advanced sleep phase. Most people usually fall on a spectrum between the two, sleeping between 10 p.m. and midnight.

Why is it important to understand your personal sleep cycle?

Whatever type you may identify with, it’s important to understand and maintain that pattern daily as much as possible. Being able to regulate your sleep cycle will have additional benefits to your overall health and well-being.

Many of us may see sleep as flexible or bonus time, and that time is the first place we can steal from. We have all scheduled early or late work activities, taken early and late flights, without considering the effect on our body’s immune, hormonal, and metabolic regulation.

It’s important to prioritize sleep, because that’s also the time during which the brain cleanses itself by releasing toxins and paving networks that allow us to maintain and expand our cognitive abilities. A simple way to do that is by organizing our personal and professional activities within the 16 hours that surround our typical eight-hour sleep period.

If your sleep timing is variable, your body rhythm will be misaligned, and you’ll experience something symptoms of fatigue, similar to a typical jet lag.

How does modern life impact natural sleep rhythms?

Stimuli like light and usage of electronics late at night leads to delayed bedtimes and people may find themselves sleeping in a delayed phase. The drawback is that often they may still need to get up early in the morning, reducing their sleep duration.

These behavioral aspects create a self-imposed sleep restriction. Work demands, school schedule, or environmental pressures may affect a person’s ability to self-regulate their sleep. If someone only gets five or six hours of sleep per night during the week because of their work schedule, they may wake up later the weekends and perceive that they are a night owl. But that may not be their natural pattern, they could just be catching up with sleep.

Look back on your sleep patterns growing up. Was it easy to get up for school? Were you up before the alarm and ready to go? Or were you always dragging and snoozing and feeling that you wanted to sleep longer?

Another way to better understand your natural sleep pattern is by analyzing your sleep routine when you’re off from work or on vacation—assuming you are not binging on electronics or partying late at night.

Can night owls become early birds, or vice versa?

Being an early bird or night owl may not be a definite diagnosis for some people, as we may identify with different chronotypes at different times in our lives.

People can also adjust the cues that your brain follows to synchronize sleep, which we call entrainment. If you want to get up earlier, start by adding light in the morning within 20 minutes of waking, and make this a daily routine. Also refrain from using electronics for 1 to 2 hours before bedtime. Exposure to darkness is a signal that helps to release melatonin. Now, if you want to go shift your sleep to a later time, you may expose yourself to lights in the late afternoon/early evening, or exercise closer to bedtime, as the increase in body temperature may also delay sleep onset. 

Ana C. Krieger, M.D., M.P.H., is director of the Center for Sleep Medicine at NewYork-Presbyterian/Weill Cornell Medical Center and Weill Cornell Medicine, as well as a professor of clinical medicine, professor of clinical genetic medicine, and professor of medicine in clinical neurology at Weill Cornell Medicine. She is board-certified in sleep medicine by the American Academy of Sleep Medicine.