We’ve all heard people complain that they wish they could be a “morning person.” Hardly anyone ever complains that they would like to be able to be a “night owl,” unless their jobs or social lives demand it. Whether you’re happy or not about your ability to get up early or stay up late, you can benefit from learning what your body’s clock is, and how you can change it to adapt to your life’s demands.
Let’s start with some basic concepts. The social clock is the one that you see and hear when you start your day and that sets the times that you go to work or school, eat, and make appointments or complete work tasks. The solar clock provides light and warmer temperatures during the day.
The biological clock controls your circadian rhythm—the physiological processes that occur repeatedly on approximately a 24-hour cycle. Some of these processes in addition to alertness include body temperature, production of the stress hormone (cortisol), and cognition (mental alertness, memory, and intelligence).
Each of us has a slight variation on this pattern leading some of us to be morning types (also called “larks”) and evening types (also called “owls”). You probably know in general how you best function, but with this quick quiz (Adan & Almirall, 1991), you’ll be able to pinpoint your type more precisely:
1. Considering only your “feeling best” rhythm, at what time would you wake up if you were entirely free to plan your day?
-  5:00-6:30 a.m.
-  6:30-7:45 a.m.
-  7:45-9:45 a.m.
-  9:45-11:00 a.m.
- 11:00 a.m.-12:00 (noon)
2. During the first half hour after waking in the morning, how tired do you feel?
-  Very tired
-  Fairly tired
-  Fairly refreshed
-  Very refreshed
3. At what time in the evening do you feel tired and in need of sleep?
-  8:00-9:00 p.m.
-  9:00-10:15 p.m.
-  10:15 p.m.-12:30 a.m.
- 12:30-1:45 a.m.
-  1:45-3:00 a.m.
4. At what time of day do you think that you reach your “feeling best” peak?
-  5–8 AM (05–08 h)
-  8–10 AM (08–10 h)
-  10 AM–5 PM (10–17 h)
-  5–10 PM (17–22 h)
-  10 PM–5 AM (22–05 h)
5. One hears about “morning” and “evening” types of people. Which ONE of these types do you consider yourself to be?
-  Definitely a morning type.
-  Rather more a morning type than an evening type.
-  Rather more an evening type than an morning type.
-  Definitely an evening type.
The numbers in brackets were the points value for each item. Now add up them up. Here’s the key to show what type you most likely are:
- 22-25 Definitely Morning (DM)
- 18-21 Moderately Morning (MM)
- 12-17 Neither (N)
- 8- 11 Moderately Evening (ME)
- 4-7 Definitely Evening (DE)
The results of this test may not have come as a complete surprise to you, as you probably knew already whether you function better in the morning or the evening. However, you might be surprised to learn that people are very good at identifying their own circadian rhythm types as judged against actual bedtimes and daily activities (Thun et al., 2012).
The standard circadian profile is the N type, which means people who wake up between 7 and 8 a.m. and go to bed between 11 p.m. and midnight. The N type is most likely to be alert in the morning and early evening and least alert in the early afternoon. The MM and ME types are still within the standard range, and show similar patterns of alertness and sleepiness, though MM’s may have trouble if they must work through the overnight hours.
The EM’s and EE’s are off by about two hours from the standard day-night cycle around which the typical work day is based. EM’s work best around 8-9 a.m. and are pretty much done for the day by 9 or 10 p.m. Therefore, their habits fit well with the typical work day. Although the EE’s can stay awake into the wee hours without much difficulty, they perform at much more poorly in the morning and, when forced to work morning schedules, become increasingly sleep-deprived.
When people are free to set their own sleep and wake times, only the EE’s stick to their preferred schedule of getting up and going to sleep early. During the work week, in contrast, everyone else suffers a slight loss of sleep, also known as sleep debt. As your sleep debt accumulates, so does your ability to carry out your daily activities without making mistakes, forgetting things, or- worse- falling asleep during a task or while driving. For the DE’s, this sleep debt can become severe. When they have free days, they try to catch up by sleeping as many extra hours as they can, possibly even as much of half of the day (Achari et al., 2012). Night owls not only perform more poorly at work but they also lose precious vacation time.
If you’re unlucky enough to be a DE, you are setting yourself up for a life filled with repeated cycles of sleep debt which you can never completely make up. As a result, you put your physical health at risk and ultimately become more susceptible to developing sleep disorders, which only further exacerbates the problem. Evening types are more likely to experience emotional instability, poorer handling of stress, and greater vulnerability to psychosomatic and psychological distress. The only way in which you benefit as a DE is if your job requires you to work late into, or throughout, the night time hours. In this case, you'll be fine for as long as you hold your job, though vacations and weekends may still remain a problem.
In a recent study, a team headed by University of Wurzburg (Germany) psychologist Karolin Roeser (2012) found that evening-types had poorer scores on several measures of cardiac functioning, including blood pressure, heart rate, and heart rate variability. They also had poorer quality of sleep, smoked more, and were less physically active than the morning types. When subjected to stress at different times of day (completing a mental arithmetic test), contrary to the prediction, morning- and evening-types responded similarly. Both morning and evening types did not handle stress in the evening as well as stress in the morning. Though not what the researchers expected, since evening types are more likely to be doing work at night, this means that they are in effect subjecting themselves to more stress in general.
If you’re a morning type, these findings should allow you to feel better about yourself when your night owl friends give you a hard time about turning in early. If you’re an evening type, though, you don’t have to be spend the rest of your life paying a steep price to your health in sleep debt. In addition to following the general tips for good sleep, here are steps you night owls can take to reset your own circadian clock:
- Uncover your hidden morning-person self. Living with neighbors, partners, and roommates who like to burn the midnight oil can cause anyone to become an evening person by default. You may actually be more of a morning person than you think you are. Don’t feel that you have to be pressured to stay up late to avoid looking like a social loser. When you’re tired, go to bed, even if your friends think you’re being lame.
- Escape the source of loud noise from your night-owl friends. Easier said than done, perhaps. My students tell me that they would love to go to sleep earlier, but the paper-thin dorm walls make it impossible. If you’re stuck in a noisy environment that you can’t control, get yourself a good set of ear protectors or headphones that play white noise. You can also ask the noisy people to stop being so noisy, citing health reasons. If all else fails, you may have to take the more radical action of moving to a quieter living situation.
- Organize your time during your waking hours. People who stay up past their preferred bedtime to finish the work they didn’t get done during the day are only adding to their woes. The further behind they get at work, the more midnight oil they have to burn for more nights. Follow the principles of effective time management and you won’t be so pressured and far behind.
- Don’t be disheartened. People tend to have a fatalistic attitude when it comes to their circadian rhythms, particularly when they don’t have an accurate read of what their circadian rhythm actually is. You may have thought you were an evening person, but perhaps you’ve discovered here that you’re not. If that’s the case, then you can definitely adjust to a healthier sleep schedule. If not, and you’re a died in the wool night owl, move on to the next step.
- Gradually retrain your circadian rhythm. Perhaps you feel that staying up late has nothing to do with your social life or your work schedule but is hard-wired into your brain. If this is the case, adjust your sleep-wake cycle little by little until you’re getting sleepy 10 minutes, then 20 minutes, and finally perhaps 30-45 minutes earlier than you have in the past. Don’t do this by building up your sleep debt- as we saw earlier, that will only reinforce erratic sleep cycles of oversleeping on your off days. Don’t rush through the steps, but give your body enough time to adjust so that the newer sleep and wake times will come more easily to you.
Scientists are discovering on virtually a daily basis that sleep is essential to our mental and physical health. We learn better, cope better with stress, and live a longer life when we can follow our body’s natural desire to rise with the sun and sleep with the moon. If you’re off that schedule by an hour or two, change is possible.
And now, I hope your day (or night) is off to a great start!
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Achari, K., Pati, A., & Parganiha, A. (2012). Comparison of distributions of morningness–eveningness among populations of shift workers on varied work patterns in different organizations. Biological Rhythm Research, 43(3), 235-248. doi:10.1080/09291016.2011.571025
Adan, A., & Almirall, H. (1991). Horne & Östberg Morningness–Eveningness questionnaire: A reduced scale. Personality And Individual Differences, 12(3), 241-253. doi:10.1016/0191-8869(91)90110-W
Horne, J.A. and Ostberg, O. (1976). A Self-Assessment Questionnaire to Determine Morningness-Eveningness in Human Circadian Rhythms. International Journal of Chronobiology, 4, 97-110.
Roeser, K., Obergfell, F., Meule, A., Vögele, C., Schlarb, A. A., & Kübler, A. (2012). Of larks and hearts—morningness/eveningness, heart rate variability and cardiovascular stress response at different times of day. Physiology & Behavior, 106(2), 151-157. doi:10.1016/j.physbeh.2012.01.023
Thun, E., Bjorvatn, B., Osland, T., Steen, V., Sivertsen, B., Johansen, T., & ... Pallesen, S. (2012). An actigraphic validation study of seven morningness-eveningness inventories. European Psychologist, 17(3), 222-230. doi:10.1027/1016-9040/a000097
Copyright Susan Krauss Whitbourne, 2012