Until recently, researchers thought there were only two kinds of people: those who vaulted out of bed easily in the morning but started to fade after dinner and those who were groggy most of the morning but were at their peak in the evenings. Depending on whether you thrive in the a.m. or the p.m., you're either a morning person or a night owl.
But if you don't see yourself in either category, new research offers two labels that might offer a better fit. A study published in the journal Personality and Individual Differences defines two new chronotypes — which are personality types based on when you're most alert and when you're most likely to want to sleep. The researchers call them the "napper" and "afternoon" chronotypes.
Here's a look at all four types so you can figure out which one you are and can plan your day (and night) accordingly. If you aren't sure, this quiz can help you narrow it down to morning and evening, but it doesn't include the newest napper and afternoon personality types.
Morning people are early risers who often wake up before their alarms, or at least have little trouble getting out of bed when it's time to start the day. They are most alert and do their best work earlier in the day and begin to fade as the day goes on. They typically go to bed early or at a fairly traditional hour.
As far as overall personality traits, Fast Company points out that morning people tend to be happier, agreeable, persistent, cooperative, conscientious, proactive and they procrastinate a lot less than night owls.
They may perform better on tests (because many exams are given first thing in the morning), but it levels out and night owls seem to top income and career categories.
There's also a new subset of morning larks that has only recently been recognized. Around one in 300 people are "extreme early birds," a term co-opted by scientists to describe advanced sleep phase (ASP), which means they get roughly the same amount of sleep as a regular early bird, but the time they wake can be anytime from 2 a.m. to 5 a.m. To make the math work out, that means they need to go to bed between 6 p.m. and 9 p.m., which can put a damper on social activities, according to the study's lead author, Dr. Louis Ptacek of the University of California San Francisco, who researches the genetics of circadian rhythm.
The research, published in the journal Sleep, also uncovered another variation on this theme: familial advanced sleep phase (FASP), which means that the genes for ASP run in the family.
In all instances, the body's signals that it's time to sleep — body temperature and melatonin levels — kick in at a different time.
Night owls would sleep in until late morning (or later) if given the chance, but often slog through the mornings, not reaching their peak until much later in the day. They're often at their best in the evenings and can toil into the wee hours, not going to bed until very late, still studying or working while others have gone to sleep.
Some studies have shown night owls are more likely to develop diabetes, muscle loss and metabolic syndrome, which includes high blood pressure, high blood sugar levels and abnormal cholesterol levels. They may also have a higher risk of early death because the hours they have to work don't match their body's internal clock.
However, while other research has found that students who are morning people might get better grades in school, night owls have the kind of intelligence that results in higher-paying jobs down the line.
The newly defined napper types are sleepiest in the afternoon vs. the morning or the evening. They start out very alert in the mornings and stay that way until about 11 a.m., according to Psychology Today. Then they get more and more drowsy, which peaks in mid-afternoon around 3 p.m. After that, they become alert again until about 10 p.m. and then get sleepy again.
Also newly defined, afternoon types are sleepy both in the morning and in the evening. Afternoon chronotypes are the most alert and at their peak in the afternoons. They start to become alert around 11 a.m. and that alertness stays high until about 5 p.m., when they become sleepy again.
Editor's note: This story has been updated with new information since it was first published in June 2019.