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Chronotypes: night owls, early birds and social jetlag.

Often it seems there is a moral judgement made about bedtime and risetime. There is that old English proverb that says “Early to bed and early to rise makes a man healthy, wealthy and wise.” Recently there has been a lot of hype promoting getting up at 5am as being the answer to success but how true is this claim?

The truth is that going to bed early and waking early may suit some people, but others struggle to do this. While it might feel like you choose your bedtime and risetime, there is actually a strong biological drive behind this choice. This refers to your chronotype: your body’s natural inclination to sleep at a certain time. Recent research shows that chronotype is strongly influenced by genetics with morningness and eveningness characteristics linked to specific genes. For this reason, it is very hard to change your chronotype, although it will alter across the lifespan, going from a tendency towards morningness in childhood, to eveningness in teenagers, then slowly advancing in the adult years back to morningness in later adulthood.

The chronotype is closely linked to the circadian rhythm. This is the internal body clock that regulates the timing of sleep and other bodily processes (for more info click the following link, why teens sleep later). The circadian rhythm can be shifted by light and following a strict sleep schedule. So, it is possible for someone who is naturally a night owl to eventually get to sleep and wake up earlier than their natural inclination if they regularly follow this routine. However, they may not feel they are at their best until later in the day.

What is your chronotype?

You probably already have a sense of your chronotype. If you are not sure, think about when you would wake or go to bed on a day you are completely free to plan, with no work or other commitments. This might be at the weekend or on holiday. There are several online questionnaires to help you determine your chronotype, the most reliable being the Morningness-Eveningness Questionnaire and the Munich Chronotype Questionnaire.

Night owls represent evening types and early birds or larks describe morning types. However, chronotypes exist on a spectrum, similar to height, with most people falling between these two extremes. The morningness-eveningness questionnaire refers to extreme morning types, moderate morning types, intermediates, moderate evening types and extreme evening types.

Variation in chronotype is thought to have occurred through natural selection to reduce the dangers that come with sleeping, such as risks from predators or environmental dangers. Hunter-gatherers shared the task of staying watch during the night to reduce this risk.

While differing chronotypes may be an advantage in hunter-gatherer populations, modern life tends to have social schedules that interfere with individual sleep preferences for many people, with early starts for school and work.

Social jetlag

Social jetlag occurs when someone’s social clock is misaligned to the circadian rhythm. This can lead to feelings of jetlag such as tiredness, dysregulation of appetite, problems sleeping, lack of concentration and sleepiness during the day. Social jetlag is seen when there is a difference in sleep timing between work or school days and free days. This leads to a large sleep debt building up during the week followed by catching up on sleep on weekends, with the latter sleep being at a time more dictated by chronotype than social schedule. This discrepancy is normally more extreme with late chronotypes.

Chronotypes, social jetlag and health

Various studies have looked at chronotype, performance, physical and mental health. Findings suggest morning types perform better academically, most likely due to the fact they get more sleep, experience less social jetlag, feel more alert in the morning when school starts and show higher attendance.

Eveningness is associated with a higher risk of mental health issues such as anxiety, depression, impulsivity, anger and substance use such as nicotine, caffeine and alcohol. In addition, this chronotype is associated with increased risk of type 2 diabetes, obesity, sleep apnea, and metabolic syndrome. These associations are very similar to those seen with sleep deprivation and are therefore likely to be due to irregular and insufficient sleep caused by wake times not suited to late chronotypes, rather than the chronotype itself.

This has led to scientists suggesting work and school schedules should be adapted to chronotype as much as possible, in order to improve workers and adolescent health. While there has been a shift towards flexible working hours, a UK feasibility study found moving school start times to be unpractical, although there has been some success in America, with late school start times leading to improved academic performance and attendance.

How to minimize social jetlag

If you have a tendency towards extreme eveningness be aware that certain behaviours can enhance this effect and worsen social jetlag. Try to stick to fairly regular sleep and wake times, seven days a week while also aiming for seven to nine hours of sleep (eight to ten hours for teenagers); get outside in natural daylight soon after waking; eat some breakfast; aim to exercise in the first half of the day and not in the evening; avoid naps after 3pm; don’t eat too late in the evening, avoid bright lights and light emitting devices in the hour or two before bed; avoid caffeine eight to ten hours before sleep; and avoid stimulating activities such as work or computer games in the hours before bed.

Christabel Majendie November 2022.

Christabel is a Bristol based sleep therapist and consultant, specialising in helping individuals experiencing a wide range of sleep problems. For more information on her work you can visit her website.

Christabel is not a brand ambassador and does not endorse any product of Sleep Well Drinks Limited.

How to manage your racing mind and get a good night’s sleep

Most people can remember a time when they have struggled to sleep because of a racing mind. This classic symptom of insomnia, referred to as hyperarousal, is common during times of stress. It may even be accompanied by the frustrating experience of feeling tired before going to bed but then feeling wired when your head hits the pillow.

A racing mind can be due to stress or anxiety but it is more likely to occur if you have not prepared well for sleep. You may need to make some changes to your usual bedtime routine to calm your mind as well as manage any stress you may be holding.

Worry Time

Scheduling worry time teaches your brain to deal with your stressors during your waking hours so you are less likely to ruminate about them in bed. Set aside 10-20 minutes in the early evening (not close to bedtime) to go through your worries. Write a list of issues then what you can do about these problems and when you will deal with them. Think about the day you have had and anything you are left worrying about. Think about what is coming up tomorrow and anything you need to add to your to do list. For big problems, break these down into manageable steps and schedule a time to deal with the next step.

Have a notebook by your bed, to capture any additional worries you think of when heading to bed. If you notice you are worrying in bed, remind yourself these thoughts are not helpful for sleep and you have a set time to go through any problems tomorrow then distract yourself with some relaxation techniques (see below).

Dim the lights

Light has the ability to suppress melatonin, the hormone that helps you to know when to go to sleep. Dimming the lights an hour before bed should be part of your bedtime routine as bright light at night can keep you alert. Use lamps instead of overhead lights and avoid light-emitting devices in this time.

Disconnect and wind down

Not only are light-emitting devices problematic because of the effect of light on the sleep systems, what you do on these devices tends to be mentally stimulating and can contribute to a racing mind. Sleep is not like turning off a light switch. You need to take time to relax before sleep. If you work up until bedtime or are racing around doing tasks, you are setting yourself up for a racing mind when you try to sleep. Reading the news, can also set off worries while social media and browsing information on your phone can keep your brain alert. Aim to finish work at a reasonable time to allow yourself to relax in the evening and have a set time, an hour before sleep, when you turn off electronics. Then stick to non-stimulating activities like reading, listening to something, meditation or a jigsaw.

Relaxation techniques

As well as helping to relax the body, relaxation exercises can help with a racing mind. Deep or diaphragmatic breathing involves a slow, regular breath from the belly. Progressive muscle relaxation is a sequence of tensing then relaxing different muscle groups around the body while working with your breath. Visit our previous post, ‘relaxation techniques to help you sleep‘ for more information on these techniques.

Going to bed when you are sleepy

Sometimes people may experience a racing mind because they are not ready to go to sleep. The timing of sleep is controlled in the body by two biological systems, the circadian rhythm which is your internal body clock, and the sleep homeostat which balances wakefulness with sleep. If you go to bed too early, these systems may not allow you to sleep. By going to bed when you feel sleepy -tired (eyes feel heavy and you feel you might nod off), you are less likely to have a racing mind and are more likely to get to sleep. This may be later than your usual time so continue to wind down in dim lights.

No clock watching

It’s tempting to check the time when you can’t sleep but this can enhance the racing mind. Clock watching leads to thoughts about how long you have been awake, how many hours you have left to sleep and how you must get to sleep soon. These thoughts can cause anxiety and frustration, emotions that don’t pair well with sleep. If you really can’t keep the phone out of the bedroom, at least keep it out of reach so you can’t check the time. Position clocks so you can’t see them in bed or remove them from the bedroom completely.

Caffeine

Caffeine is a stimulant; it suppresses sleepiness and keeps you alert. It has a long half-life so it takes a while for it to be broken down in the body. If you are experiencing a racing mind at night, try cutting out caffeine ten hours before bedtime.

Keep the bed for sleep

If you do lots of things in bed like browsing on the phone, checking emails, watching TV, drinking cups of tea, the purpose of the bed becomes confused in your brain. You want to keep the bed for sleep (sex is the only exception) so these things become associated together.

For this reason, it’s also a good idea to get out of bed if you are struggling to sleep for more than an estimated 20 minutes (remember no clock watching). Do something relaxing, in dim lights until you feel sleepy then head back to bed.

Christabel Majendie November 2022.

Christabel is a Bristol based sleep therapist and consultant, specialising in helping individuals experiencing a wide range of sleep problems. For more information on her work you can visit her website.

Christabel Majendie is not a brand ambassador and does not endorse any product of Sleep Well Drinks Limited.