Many people feel they are experiencing an exacerbation in their mental health symptoms under lock down. In my therapy practice, patients are increasingly telling me that they struggle with worsening low mood and lack of energy. They also report that their daily routines have changed: Since many of us do not have to get up on time for work or school, our daily routines have become more variable, and sleep problems are also a little more common. In this article I explore the links between disrupted routines, sleep, and the body’s time keeping. In the process I came across some incredibly interesting research, including a French geophysicist who was fascinated by the opening and closing of the leaves of his Mimosa plants, the pioneering sleep researcher who went to live in absolute darkness deep inside a cave for six weeks, and an unusual psychotherapy for people with mood disorders that may just hold the key to recovering your vitality if you, too, have found your mood and energy levels declining under lock down.
My thanks to Dr David Lee, Clinical Director at Sleep Unlimited, whose excellent guest article on sleep is due to be published here in the next few days, for his helpful advice on the topics covered in this piece.
What has happened to your daily routine during the Covid-19 lock down? Have you found it increasingly difficult to get up in the mornings? Has your motivation flagged? Or perhaps you have started to struggle with low mood and lack of energy on most days? You might also have noticed some changes in your routine: A temptation to go to bed a little later than usual, not having your meals at quite the same times as before, and perhaps a bit more procrastination than you’re used to? Does this picture fit your experience over the last few weeks?
And how about your sleep? Many of my patients report that their sleep has become significantly poorer since the lock down. Some also report low mood, low motivation, and feeling depleted almost every day. They wonder if it is an exacerbation of their mental health problems – which may well be the case for some, but I found some intriguing research that show that their experience could possibly also be explained in the light of insights from the scientific study of chronobiology – a branch of biology interested in the neurological, chemical and physiological mechanisms by which organisms keep time.
If you have been affected in these ways, then you may be experiencing what researchers call social jetlag. Social jetlag occurs when a mismatch arises between your body’s internal time keeping and your “social” time keeping. People who struggle with social jetlag often find that they develop a sleep debt and have to catch up with lost sleep over weekends, or through daytime napping.
You are especially at risk of social jetlag if you are a shift worker, and under lock down, of course, if you are furloughed, a student not attending school or college, or in fact anyone who had to make major changes to their daily life during this crisis (and that includes most of us!). You may have noticed that you somehow miss the regular aspects of your daily routines: Having to get up on time for work or lectures, eating meals at more or less regular times, and, of course, your regular bedtime.
Researchers have demonstrated relationships between chronic social jetlag and such unhealthy behaviours as smoking, the amount of caffeinated drinks taken during the day, physical inactivity, and increased risks for diabetes and cardiovascular disease. These risks are worrisome, especially when taking a long term view, but there are also more immediate risks associated with social jet lag.
Social jetlag is correlated with symptoms of depression in a wide range of people.
Firstly, social jetlag is correlated with symptoms of depression in a wide range of people. And key among the symptoms of depressive illnesses are low or irritable mood, loss of interest in previously valued activities, and loss of motivation.
Secondly, research done in Northern Russia by Artem Polugrudov and his co-workers at the Russian Academy of Science found that, in people with social jetlag, the natural variation in human body temperature (higher while we sleep, and lower during the day while we are awake), is suppressed (in other words the naturally occurring variations between high and low body temperature over the course of a day is reduced). Social jetlag is accompanied by a slightly higher temperature while we are awake and a slightly lower temperature while we are asleep. This is important because our daily body temperature cycle is a critical factor in the timing of sleep in humans. It is therefore not surprising that social jetlag is associated with poor sleep. A further interesting finding of this research was that the levels of depression and anxiety they measured in females with social jetlag was significantly higher than in males. So it does seem that the emotional impact of social jetlag is worse for women than for men!
Why is it so important to know about the implications of social jetlag in the present crisis? Social jetlag results from a misalignment between the way we live our lives and the natural, built in biological rhythms that determine so many aspects of our biological functioning and by extension, our psychological well-being.
Over the last 75 years Chronobiologists have made major advances in our understanding of how biological time keeping works and have found a variety of biological clocks almost everywhere in nature. Starting as early as the 1700s, biologists observed periodic movements in the leaves of plants. One of the early pioneers of this work was Jean Jacques de Mairan, an astronomer and geophysicist who became fascinated by the rhythmic opening and closing of the leaves of his Mimosa plants. Through a simple experiment (keeping the plant isolated from light and temperature variations), he demonstrated that the plant continued to open and close its leaves much as before, concluding that there must be a built in time keeping mechanism in the biology of the plant. (This conclusion remained controversial until more recent research uncovered some of the biochemistry and genetics that drive plants’ biological clocks and research by NASA on plants in space demonstrated the continuation of circadian rhythms in organisms despite the absence of external cues, including gravity!)
In humans, an ingenious experiment back in the 1930s by Nathaniel Kleitman and his research assistant, Bruce Richardson, showed both the cyclic nature of many of our biological rhythms and what happens if we remove the regular variation of day and night from the equation: For six weeks the men went to live in almost total darkness inside a cave, aptly called Mammoth Cave, cut off completely from all daylight. They took a number of scientific instruments with them to measure their body physiology and sleep patterns under the experimental conditions. In the end, they did not last the full six weeks, but after 32 days, armed with the data they collected, they were able to demonstrate two important findings: First of all, that the human body, even in the absence of the day-night cycle has an inherent biological rhythm that manifests itself in many different cycles such as daily rhythmic variations in body temperature, and, of course, sleep. And secondly, the inherent, natural rhythm in humans was close to 24 hours, but not exactly 24 hours. The body clock’s “day” is a little longer than 24 hours. In fact, since their original study, it has been shown that the average adult’s body clock runs at about 24 hours and 15 minutes. Without external cues to synchronise our body clocks, they tend to revert back to their natural rhythm, which tends to take us to a longer “day” than 24 hours.
In the decades since these studies, numerous further investigations have explored how our biological clocks operate and the importance of biological rhythms for our health and well-being. This research has shown that we have a number of internal biological rhythms that operate broadly on a 24 hour cycle. These include blood pressure, body temperature, cortisol release, sleep, and mental alertness. And all of these clocks are synchronised by the body’s master clock which has been located in a part of the brain called the suprachiasmatic nucleus or SCN. (The SCN is a cluster of neurons in the part of the brain called the hypothalamus which is roughly located in the centre of the brain, above the brain stem.)
The most important cue for synchronising the SCN is natural daylight. However, the most important cues for how we live our lives are “social time”: when we get up, have our meals, socialise and go to bed. These are determined by work-arrangements, lifestyle and where we live.
For example, all of us live in designated time zones, based on a set of reference meridians 15 degrees apart and centred on the Greenwich Meridian in London. The time measurements that we live by are based on these geographical time zones. But as we move towards the eastern and western borders of our time zones, the discrepancies between the natural day and our biological clocks increase, causing our social time and the natural time of our body clocks to be out of sync. There is some intriguing research that indicates the possibility that people who live close to the edges of time zones are more likely to suffer from social jet lag.
Other factors that affect the synchronisation between our body clocks and social time, include work patterns such as shift work, exposure to bright light (blue light has been found in more recent research to be a particular concern), and irregular meal times (which affects glucose metabolism among other things).
Why is all this so important? As I mentioned earlier, disturbances in our daily circadian rhythms, have been implicated in a number of chronic health problems and also in mood disorders. In fact, Professor Ellen Frank, a psychologist at the University of Pittsburg in the United States, has put forward a theory of mood disorders that conceptualise some of the core impairments in conditions such as bipolar disorder as a disturbance in the stability of social rhythms. Professor Frank and her colleagues have developed a treatment program based on this theory and have shown promising outcomes in treating individuals with mood disorders using social rhythm therapy (based on this theory) alongside other therapeutic approaches.
In social rhythm theory, the irregularities in the social rhythms of our lives are a key to understanding the day to day variations in our mood and vitality: When we live our lives close to an ideal, regular pattern, our social and biological clocks tend to be more or less consistently related and we can adapt our biology to our lifestyle; when our patterns become irregular, the degree of synchronisation between our social and biological rhythms is variable and this leads to a mismatch between the body’s physiological processes and environmental requirements. For example, in order for our glucose metabolism to work optimally, the pancreas has to secrete the correct hormones that metabolise glucose at the right times. These are controlled by a circadian clock, ultimately synchronised to daylight by the SCN, and so misalignment can affect our metabolism and by implication, mental alertness and energy levels.
Irregularities in the social rhythms of our lives can explain some of the day to day variations in our mood and vitality.
In her research, Professor Frank found five key indicators that can help provide a snapshot of the regularity of our social rhythms: When we get up out of bed in the day, when we go to bed at night, our first contact with another person, when we start work or school, and dinner time.
When you consider your social rhythms during lock down, to what extent have you maintained regularity in these five areas? Chances are that, like so many of us, your routine is now very different from before the lock down and possibly more variable. Perhaps you found that your bedtime has drifted a little later than before? You might get up later too, and perhaps take a bit longer to get going in the mornings?
The key question to ask though, is how regular is your new routine? Biologically, the difficulty with adjusting comes primarily from the irregularity of the new social rhythms brought about by lock down: With schools closed and many workplaces shut, there is no external pressure to get up on time, and little need to go to bed at a consistent time. It is easy to drift into a poor mealtime routine too and all these small changes can add up to a more variable daily schedule than our bodies are wired for.
How can we address this? Ellen Frank’s Social Rhythm Therapy may hold some clues. The first step would be to assess the regularity of your current weekly schedule. Monitor your daily social rhythms across the five domains mentioned earlier. Write down the times you actually engage in the activities listed: What time do you get up? What time do you have your first contact with another person? When do you start with your daily tasks (which could be cleaning, home schooling, volunteering, or work)? When do you have your dinner? And, when do you go to bed? If your days are varied, for instance, you work only part time, then note how your schedule varies between work days and days you are off.
Once you have monitored your social rhythms over a period of approximately one week, you will have a good idea how much variation there is. You can now compare them with daily life before lockdown. Is life now very different or more or less the same?
The five key indicators of social rhythms:
1. Time you got up in the day.
2. Time of first contact with another person.
3. Time you started your daily tasks/work.
4. Time of your dinner.
5. Time you went to bed.
The next step is the critical one: Social rhythm therapy encourages people to design and keep to a consistent schedule that is as close as possible to their natural biological rhythms. For each person this is different, so you will have to work out your own ideal schedule and try to stick to it, even if you don’t feel like it. In a perfect world, your social rhythms would be more or less consistent from day to day – and that should include weekends. If, because of shift work or other constraints on you, you cannot have an ideal and consistent schedule, try at least to make your ideal schedule as regular as you can.
The next challenge is to start working on living to the schedule you have designed for yourself. Resist the temptation to watch that extra episode from the box set you have become hooked on and go to bed when you feel your body is telling you that its time. If you force yourself to stay awake, even if only for another 30 minutes or so, you may find it really difficult to go to sleep. Almost as if, by staying awake a bit longer, you managed to get a surge of fresh energy. And the reasons for this resurgence in wakefulness is also explained by research into our biological clocks.
Back in the early 1960s, Nathaniel Kleitman, the same academic who went to live in Mammoth Cave, introduced the idea that our daily circadian rhythms are accompanied by a faster cyclic pattern which he called the Basic Rest Activity Cycle (BRAC). These BRAC cycles occur throughout the day and night and last for about 90 minutes in adult humans. At the peaks in our BRACs, we are more vigilant and feel a bit more awake; at their troughs, we have a little less energy and feel more lethargic or sleepy. That mid-morning yawn is a dead giveaway of a BRAC trough! Our BRAC cycles (also sometimes referred to as ultradian rhythms), are very helpful in understanding widely observed variations in cognitive performance and alertness across the workday. You can blame your BRACs for the infamous post-lunch dip in energy and that mid-morning craving for caffeine or chocolate!
Our daily circadian rhythms are accompanied by a faster cyclic pattern called the Basic Rest Activity Cycle (BRAC). BRAC cycles occur throughout the day and night and last for about 90 minutes.
BRACs also make for useful markers of our own bodily rhythms: For example, you can work out an ideal bedtime using your BRACs by doing the following: Take note of a time during the day when you feel really sleepy; chances are you are now in one of those ultradian dips. Now count forward in steps of 90 minutes to work out an ideal bedtime for yourself when you will be at the bottom of another dip. Take care not to do anything that will keep you awake beyond this time, for example, eating food or using screens just before or during your “dip”. If you do find that you were unable to resist the temptation to watch another hour of television, just bear in mind that your next dip is likely to be a full 90 minutes away, and you may need at least 30 minutes of wind down time to have the best chance to fall asleep easily if you go to bed then. So, get ready by switching off all screens, dim the lights, and prepare for bed!
On the other hand, if you try to go to bed at a peak in your ultradian cycle, chances are that you will struggle; you might feel strangely awake and energetic, and your mind might just be too busy for you to fall asleep quickly. It may be best for you to wait until you hit the next dip!
The research we have looked at in this article indicate that when our social rhythms are disrupted and our routines out of sync with our body clocks, we are at risk of experiencing poor sleep, low mood and a lack of vitality. Social rhythm therapy provides us with pointers on how to re-create a consistent and regular routine that suits our needs, and encourages us to stick to the routine even if it is very tempting to deviate, especially as so many of us are experiencing disruptions to our daily lives during the lock down. The outcomes of social rhythm therapy in people with mood disorders have demonstrated that keeping to a regular and consistent schedule can lead to more stable mood and improved mental health. So, if you think that you are experiencing the symptoms of social jetlag as described here, have a go at analysing your own schedule as described earlier and see if you can design an ideal schedule for yourself and stick to it, however difficult it is. You may just find that by doing so, you benefit from more energy and vitality, despite the constraints imposed by the current crisis. What do you have to lose?
As the research considered here showed, having a regular schedule can help with enhancing your well-being. A crucial part of that is to get adequate sleep. That is why we are publishing a very interesting contribution by Dr David Lee, a psychologist and sleep expert to accompany this piece. In his article, Dr Lee explains the science of sleep and some of the many exciting research findings that help explain why we need to sleep and the impact of poor sleep on our health and well-being. The article also provides a link to Dr Lee’s own blog where there are some helpful resources you can use to help improve your own sleep.
If you want to find out more about other steps you can take to stay mentally well during the lock down, why not read the articles on this website about the Covid-19 Five-a-day. You can download a flyer with a summary of these 5 daily goals here.
There is a lot of fascinating research on chronobiology and sleep freely available online. Of particular use in compiling this article was the following sources, many of which can be found in full text format online:
Charles, A. C., Janet, C. Z., Joseph, M. R., Martin, C. M. E., & Elliot, D. W. (1980). Timing of REM sleep is coupled to the circadian rhythm of body temperature in man. Sleep, 2(3), 329-346.
Evans, J., & Silver, R. (2016). The suprachiasmatic nucleus and the circadian timekeeping system of the body. In Pfaf, D & Volkov, N. (Eds). Neuroscience in the 21st Century. New York (NY): Springer, pp 2241-88.
Frank, E. (2007). Treating bipolar disorder: A clinician’s guide to interpersonal and social rhythm therapy. Guilford Press.
Lee, D. R. (2018). Teaching the World to Sleep: Psychological and Behavioural Assessment and Treatment Strategies for People with Sleeping Problems and Insomnia. Routledge.
Lee, E., & Kim, M. (2019). Light and Life at Night as Circadian Rhythm Disruptors. Chronobiology in Medicine, 1(3), 95-102.
Lloyd, D. (2016). Biological timekeeping: the business of a blind watchmaker. Science Progress, 99(2), 113-132.
Polugrudov, A. S., Panev, A. S., Smirnov, V. V., Paderin, N. M., Borisenkov, M. F., & Popov, S. V. (2016). Wrist temperature and cortisol awakening response in humans with social jetlag in the North. Chronobiology international, 33(7), 802-809.
Roenneberg, T., & Merrow, M. (2016). The circadian clock and human health. Current biology, 26(10), R432-R443.
Walker, M. (2017). Why we sleep: The new science of sleep and dreams. Penguin UK.
Wittmann, M., Dinich, J., Merrow, M., & Roenneberg, T. (2006). Social jetlag: misalignment of biological and social time. Chronobiology international, 23(1-2), 497-509.
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