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Are you an Early Bird or a Night Owl?
All over the world, we keep our digital clocks synchronized, and set our morning alarms to suit work and school start times. But if you let your body run on natural time, would it choose these waking and bedtime hours?
The average person’s circadian cycle (body clock) runs at slightly over 24 hours, and resynchronizes daily with environmental triggers. There is a small window of genetic variation, and some people may run a cycle as short as 23 ½ hours (Early Birds), while others’ clocks may run up to 24 ½ hours (Night Owls).
An individual’s chronotype (clock-length) is genetically determined, so people will generally have the same tendencies as other family members, although, due to work or lifestyle routines, they may not live out their natural tendency. For example, a person may be in the habit of sleeping late because they worked an evening shift for 10 years, and shaped their lifestyle around that, but their body may actually prefer to be up and about at 6am.
While this window of genetic variation in clock-length is tiny, it actually creates a surprising amount of difference in people’s natural rhythms and some quite specific sleep-wake requirements. Regardless of how golden our reasons for living as we do, there’s simply no way around the fact that if we force our body out of its natural rhythm, we will suffer. The payment may be inflammatory disease, mood problems or simply bad decision-making, but something will give. So, be observant of your own natural tendencies, and see where you can adjust your lifestyle for best performance and optimum health.
About 10% of the population are genetic early-birds. Their clocks have the most rigid circadian parameters, and they feel the impact, more than the rest, of living out of synch with their natural cycle. About 50% are genetic night owls, and have the most flexible clocks (within limited parameters). The rest of the population falls somewhere in the middle, with more flexibility than early birds but much less than the owls.
Our personality and lifestyles evolve around what makes us comfortable, so it’s no surprise that early birds, with their strict circadian structure, tend to be more practical, rational and reliable, while night owls tend to be more creative and flexible (in both routines and morals!) Early birds are more likely to naturally develop a lifestyle which suits their chronotype, simply because it is too disruptive not to. It’s the other 90%, the average Joe’s and the night owls, who could stray a lot further before subtle problems finally become evident.
As the names suggest, early birds power up earlier in the morning, but also begin to flag earlier in the evening, while night owls are slow to get going in the morning, but can continue functioning for longer once they do. All the body’s metabolic circadian fluctuations, which have their set patterns within the daily cycle, are simply shifted forward or back a bit in time, according to individual chronotypes. For example, core body temperature has its highest peak in the evening, around 9-10pm for the average person, and its lowest point shortly before wake-up time. In an early bird, highest body temperature may occur as early as 8pm, and for a night owl, as late as 11pm.
Melatonin, which primes the body for sleep, is usually released about 14 hours after first morning light exposure, and it takes about 2 hours to build up and make us feel sleepy. Setting aside seasonal variations in daylight length, early birds will usually see first light at dawn (about 5-6am) so they will start producing melatonin around 7-8pm and be in bed by 9-10pm. Since night owls may not wake naturally until 8-9am, they won’t begin producing melatonin until about 9-10pm and may not get to bed until 1am. The average person, in a natural rhythm, will generally be up by 6-7am and asleep by 10-11pm.
Having a more flexible circadian structure, night owls can often push themselves way past their usual bedtime, and manage to stay awake, but early birds have no such ability to resist the call for sleep. They need to get to bed on time or simply fall asleep where they sit! During sleep deprivation experiments, early birds experienced much greater drowsiness and worse concentration than night owls and, when they finally got to sleep, had to spend more time in deep sleep to recover (so they had less time for dreaming). But regardless of how easily a person can push beyond their limits, each individual will have their most nourishing sleep during the optimum period defined by their chronotype.
Early birds tend to have a good appetite for breakfast in the morning, while night owls might just manage a late brunch. Due to the tendency to stay up later than they should, night owls are more inclined to late-night snacks. The body, however, cannot use the calorie input overnight and will simply add it to fat stores. As a result, more night owls than early birds tend to be over-weight.
Night owls are also more likely to get into erratic sleep patterns, experience sleep loss, and not enough morning light exposure, all factors which contribute to mood disorders. Depressive patterns are more common in night owls than early birds, and a consistent regular sleep-wake routine is known to improve mood imbalances.
When it comes to complex brain activities, like creative thought and problem-solving, early birds are fully functional first thing in the morning, while night owls take longer to plug in their brain. Once they do, though, they can sustain cognitive functionality well into the evening, while early birds tend to lose it much earlier.
Academic statistics reveal that early birds tend to have better results than night owls, because school-day structure and early start times leave night owl teens at a disadvantage. Several high schools in the US and UK experimented with later start times and found improved grades as well as better attendance.
Unfortunately, our society is set up so that kids must go to school and adults must work. Adults have some degree of choice about working hours and may manage to bring these into sync with their natural rhythms. Kids don’t really have a choice, so help them stay in touch with their flow in other ways, and on other days, so they can grow into healthier, happier adults.
The best way to assess your body’s natural sleep-wake rhythm is to take a sleeping holiday.
If possible, give yourself a week or two with no early or late commitments. First, let yourself sleep as much as desired. Put your alarm clock away. Get up late, go to bed early, and even take an afternoon nap if you still feel tired. Ensure that you expose your eyes to daylight as soon as you get up each day, whatever the time. Have your morning cuppa outside or just take a wander around the yard. After a while, your system will catch up on lost sleep and start to find its rhythm. Don’t do anything to interfere with this as it comes in. Go to bed as soon as you feel sleepy, even if it seems early. Get out of bed as soon as you feel awake and see the morning light. Your sleep-wake times may vary initially but you will gradually start to see a repeated pattern emerging, and feel more energetic and clear through the day.
You might be surprised to find that you’re not who you thought you were!
Burgess, H.J, Savic, N, Sletten, T, Roach, G, Gilbert, S.S, Dawson, D, 2003, The Relationship Between the Dim Light Melatonin Onset and Sleep on a Regular Schedule in Young Healthy Adults, Behavioural Sleep Medicine, 1(2):102-114
Gaggioni, G, Maquet, P, Schmidt, C, Dijk, D.J, Vandewalle, G, 2014, Neuroimaging, cognition, light and circadian rhythms, Frontiers in Systems Neuroscience, Vol 8:126
Giampietro, M, Cavallera, G.M, 2006, Morning and Evening Types and Creative Thinking, Personality and Individual Differences, 42(3),453-46
Kennaway, D, 1997, Melatonin: What's all the fuss about?, Australian Prescriber Magazine, 20:98
Preckel, F, Lipnevich, A, Boehme, K, Brandner, L, Georgi, K, Konen, T, Mursin, K, Roberts, R, 2013, Morningness¬Eveningness and Educational Outcomes: The Lark has an Advantage Over the Owl at High School, BritishJournal of Educational Psychology, 83(1),114-34
Stolarski, M, Ledzinska, M, Matthews, G, 2013, Morning is Tomorrow, Evening is Today: Relationships Between Chronotype and Time Perspective, Biological Rhythm Research, 44, 181-96
Wiseman, R, 2014, Night School: Wake up to the Power of Sleep, Macmillan Publishers Limited, London UK