THE TOURISM BROCHURE for the German spa town of Bad Kissingen features a photograph of a young woman on its cover. Dressed in white shorts and a pink vest, the woman is perched peacefully on a sunny rock overlooking a river, reading a handwritten journal. Emblazoned on the top left of the page is the slogan: Entdecke die Zeit – Discover Time.
In the nineteenth century, Bad Kissingen was a fashionable resort for the European aristocracy and bourgeoisie. They came for rest and relaxation; soaking up the classical architecture and fragrant rose gardens, and taking the mineral-rich waters, which (although they may taste of rusty nails) were reputed to cure all manner of ills.
Today, Bad Kissingen is pushing the discovery of a different kind of time; it has rebranded itself as the world’s first Chronocity – a place where internal time is as important as external time, and sleep is sacrosanct.
In this book, we’ve looked at the many ways that we – as individuals – can forge a healthier relationship with light. Yet most of us are not free to choose our work or school hours; we have little control over the lighting in our public spaces and external environment; and we are even forced to reprogramme our internal clockwork twice a year because of daylight saving time.
So what changes could society make to better accommodate our body clocks?
Located in the sparsely populated region of Lower Franconia in Bavaria, Bad Kissingen may seem a strange place to start a revolution. But in some ways its geographical location at the heart of Germany – and, indeed, of Europe – makes it the perfect spot to seed an idea that could spread its tendrils far and wide.
This idea germinated in the mind of Michael Wieden, Bad Kissingen’s business manager, in 2013. Having followed scientific developments in the field of chronobiology with interest, Wieden realised that, not only could weaving these principles into the town’s fabric benefit its residents, it would also make Bad Kissingen stand out from other rival spa towns.
Bad Kissingen has always been about healing and health, he reasoned; so what better way to heal our modern society than by bringing it back into contact with natural light and sleep. Tourists could come and learn about the importance of internal time, then return home and implement the lessons in their everyday lives.
Wieden contacted a chronobiologist called Thomas Kantermann, who was similarly enthused by the idea. As a teenager, Kantermann frequently found himself in the school principal’s office, having pushed the boundaries a little too far; now here was a new set of barriers to break down.1 Kantermann was ready to launch a revolution in the way that society prioritises sleep.
Quickly, the two men began drawing up a manifesto of the things they’d like to change: schools should start later, children educated outdoors where possible, and examinations not conducted in the mornings; businesses be encouraged to offer flexitime, allowing later chronotypes to work and study when they felt at their best; health clinics could pioneer chronotherapies, tailoring drug treatments to patients’ internal time; hotels might offer guests variable meal- and check-out times; and buildings should be modified to let in more daylight.
In July 2013, Kantermann and Wieden, together with Bad Kissingen’s mayor and town council, and Kantermann’s academic colleagues, signed a letter of intent in which they pledged to promote chronobiology research in the town, and to make Bad Kissingen the first in the world to ‘realise scientific field studies in a wider context’.2
Most controversial of all was their suggestion that Bad Kissingen should split from the rest of Germany and do away with daylight saving time (DST) – the practice of advancing clocks during summer months in order to make the evening daylight last longer.
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Since 1884, the world has been subdivided into twenty-four time zones, all referring to the longitudinal meridian that crosses the Greenwich observatory in London, hence the name Greenwich Mean Time (GMT). Moreover, roughly a quarter of the world’s population – including most of the inhabitants of Western Europe, Canada, most of the US and parts of Australia – also change their clocks twice a year.3
The original idea of DST is attributed to Benjamin Franklin, who voiced concerns about energy consumption during dark autumn and winter evenings as early as 1784. Even now, lighting accounts for 19 per cent of global electricity consumption and approximately 6 per cent of worldwide carbon dioxide emissions, which is yet another reason to light our homes less during the evenings.
However, it wasn’t until 1907 that an Englishman called William Willett self-published a pamphlet, The Waste of Daylight, and persuaded politicians to argue his ideas about changing the clocks through the British parliament. Willett believed that aligning work hours closer to sunrise (at least in cities)4 might encourage people to participate in more outdoor recreation, enhancing their physical well-being, and might keep them out of pubs, reduce industrial energy consumption, and facilitate military training in the evenings.
Sadly, Willett died of influenza a year before his dream was realised: the UK adopted DST in 1916, followed by the US in 1918. Even so, as Winston Churchill noted, Willett ‘has the monument he would have wished in the thousands of playing-fields crowded with eager young people every fine evening throughout the summer and one of the finest epitaphs that any man could win: He gave more light to his countrymen.’5
There was a significant downside, however – grasped by a fierce opponent of the change, John Milne, who wrote in the British Medical Journal, ‘for a certain period twice a year, the efficiency of the worker will be somewhat dampened’.6
By moving the clocks forwards each spring and backwards each autumn, we are creating another form of social jet lag. One study of American high school students – a population that’s already sleep-deprived – suggested that their sleep was curtailed by 32 minutes per night during the week following the spring clock change; they experienced a short-term reduction in reaction speeds and lapses in vigilance as well.7 Maths and science test scores fall in the week following the start of DST among young adolescents, while one American study found lower annual scores for the SAT tests, which are used to decide university admissions, among US counties that observe DST, compared with those that don’t.8
In adults, the transition to summer time and the sleep deprivation it causes has been associated with a 6 per cent increase in ‘cyberloafing’ – spending one’s work time on non-work-related websites, such as those purveying photos of cute kittens – on the Monday after the change compared with the week before;9 as well as an increase in accidental deaths and injuries, including road traffic accidents. US judges have even been found to dole out heftier sentences for the same crimes in the week after the transition. From a health perspective, clock changes have been tied to an elevated risk of heart attacks, strokes, suicide attempts and psychiatric admissions.
Hubertus Hilgers was seventeen when Germany adopted daylight saving time in 1980. Living in the countryside as he did, this meant getting up at 5 a.m., rather than 6 a.m., in order to catch the bus to school, which began at 8 a.m. ‘Already, I was finding it difficult to get to sleep at night until after midnight or 1 a.m., and so the next day I really struggled to get out of bed. My school notes got far worse and my grades deteriorated during the half-year that we had summer time, and then improved when we switched back to normal time.’
Hilgers now lives on permanent winter time – ‘normal time’, as he calls it – in defiance of the rest of German society. Arranging to meet him in the town of Erfurt, a short train ride from Bad Kissingen, involved a layer of mental arithmetic, which he claims keeps the brain sharp, although for me – and doubtless many others he interacts with – it was a pain.
Yet, many find sympathy with his arguments about daylight saving time. In 2015, he launched an online petition, Beibehaltung der normalzeit (retaining normal time), which garnered 55,000 online signatures, plus an additional 12,000 handwritten ones – which was enough to get the national newspapers to take an interest. The petition prompted widespread debate in Germany.
The discussions around Bad Kissingen reignited that debate. If it had rejected daylight saving time, as Kantermann and Wieden campaigned for it to do, Bad Kissingen would have become the DST-free town in Europe: ‘Every individual and business would have got a big publicity boost from doing that,’ says the chronobiologist Till Roenneberg, who also supports the scrapping of the twice annual changeover.
Deliberately putting oneself in such temporal isolation may sound extreme, but there are precedents. For more than half a century, the US state of Arizona has declined to join the rest of the country in its annual spring leap forward to DST – although the Navaho Reservation, which is inside its borders, does. Moreover, the Hopi Reservation, which is inside the Navaho Reservation, follows the rest of Arizona in remaining on winter time – creating a kind of guerrilla doughnut within an already mutinous state. And, until 2005, some counties and cities in Western Indiana observed daylight saving while others did not.
In the end, the Bad Kissingen town council defeated the motion to become DST-free. But even if the town isn’t ready to become a poster child for the anti-DST movement, momentum is building elsewhere – in Finland, for instance, where it’s light virtually all of the time during summer, but they still suffer the social jet lag caused by the time shift. The EU Commission also recently proposed abolishing DST – although it requires support from the twenty-eight national governments and MEPs before anything changes.10 Meanwhile, in southern England many would like to see the entire country shifted permanently forward into Central European Time,11 given that, in Britain, the annual changing of clocks back to winter time means that it gets dark as early as 4 p.m. in December and early January.
This all goes to highlight a central point: our biology is tethered to the sun, yet the clocks society uses to keep time are influenced by a tangled web of political and historical factors.
Take Germany as an example. At its widest point, the country extends across nine degrees of longitude, and the sun takes 4 minutes to pass over each of them, which means that the sun rises 36 minutes earlier at its eastern border compared to its western one. In a country with the same time zone – and the same TV and radio shows, school start times, and work culture – you might expect that everyone would rise at more or less the same time, but Roenneberg has demonstrated that people’s chronotype – the normal time they wake and go to sleep each day – is shackled to sunrise. On average, Germans wake up 4 minutes later for every degree of longitude you travel west, meaning that those in the extreme east rise 36 minutes earlier, on average, than those living in the extreme west of the country.12 A similar pattern13 has been documented in the US, where those living on the eastern edge of its time zones are more lark-like than those on the western edge, where the sun rises later.
In some cases, this discrepancy between external and internal time is enormous. A key reason why the Spaniards eat dinner so late is because – positioned as they are at the extreme west of the Central European time zone – 10 p.m. is in fact 7.30 p.m. according to their internal time, which is set according to sunrise.
If the UK advanced its clocks to match Germany and France, this would expose people to more light in the evenings, but not the mornings, pushing our internal clocks even later. Yet we’d still be having to get up at the same time each day to go to work or school, potentially making social jet lag even worse. And in mid-December, a switch to CET would mean that the sun would rise in London at 9 a.m., while in Glasgow this would occur at 9.40 a.m. Many office workers would be arriving at their desks while it was still dark outside. The sun would then set at 5 p.m. in London, meaning that the standard nine-to-five worker who didn’t go outdoors at lunchtime would spend several months of winter seeing practically no daylight at all.
Russia, which switched to permanent summer time in 2011, performed an abrupt U-turn just three years later, citing the ill health and accidents it caused.14 Sergei Kalashnikov, the chair of the State Duma Heath Committee, claimed that the switch condemned Russians to increased stress and worsening health, because of having to travel to work or school in pitch darkness. It was also blamed for an increase in morning road accidents. Since 2014, at least some parts of Russia have switched to living on permanent winter time. However, Muscovites now complain of the insomnia brought about by early sunrises during summer, and sales of blackout blinds have soared, which just goes to illustrate the complexity of the issue and how hard it is to get right.
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Yet if we could find a way to cater better to individual groups’ circadian needs, perhaps some of the heat would be taken out of the DST debate.
There are few members of society who more obviously find it hard to conform to the early-bird demands of society than teenagers.
Perhaps it’s unsurprising, then, that one of Bad Kissingen’s most enthusiastic early adopters of the Chronocity idea was the local secondary school, the Jack Steinberger Gymnasium, which caters for around 900 pupils aged ten to eighteen. Here, a group of older students created a questionnaire and canvassed their fellow pupils about whether it would be desirable to start school at 9 a.m., rather than 8 a.m.: the majority said it would. They also chronotyped the entire school and calculated the amount of social jet lag its pupils were suffering from each week. Approximately 40 per cent were experiencing two to four hours of social jet lag,15 while a further 10 per cent were contending with four to six hours – equivalent to flying from Berlin to Bangkok and back – each week. Although almost three quarters of adults experience an hour or more of social jet lag per week, only a third experience two or more hours.16
As we’ve seen, teenagers are at greater risk of social jet lag because their biological rhythms are naturally shifted later. This makes it harder for them to fall asleep at night, and yet they still must get up in the morning to go to school. To compensate for the sleep deprivation this causes, they then sleep in at weekends.17
Teenagers’ later chronotype also means that their natural peaks in logical reasoning and alertness occur later than they do in adults. In one study,18 Canadian researchers compared the cognitive performance of teenagers and adults during the mid-morning, and again, mid-afternoon. The teens’ scores improved by 10 per cent in the afternoon, whereas the adults’ scores deteriorated by 7 per cent.
One strategy for dealing with this issue is to delay school start times and allow teenagers to sleep for longer in the mornings, as the Jack Steinberger pupils proposed. The US Midwest state of Minnesota was among the first to investigate the benefits of doing so, after the Minnesota Medical Association sent a memo to all school districts urging them to do something to improve adolescent sleep. As a result, several high schools in the Minneapolis suburb of Edina changed their start time from 7.20 a.m. to 8.30 a.m.19 When researchers from the University of Minnesota investigated the impact of the change, they were surprised to find almost unanimous support for it among students, teachers and parents. Despite parents’ fears that they’d use it as an excuse for going to bed later, the teen’s bedtimes remained relatively unchanged, but they slept later in the mornings and got more sleep overall. Students said that they felt less tired during the day and thought that their grades had improved, while teachers noticed fewer pupils with their heads down on their desks and reported that the children seemed more engaged and focused. School attendance also improved.20
As news of this success began to spread, other schools started changing their hours as well, but no one had done a proper before – and after – study confirming that it made a real difference. Judith Owens is a paediatrician with a particular interest in sleep medicine. When she was called in by her daughter’s high school to talk to staff about the potential benefits of starting school 30 minutes later as they had been discussing, she agreed and decided to see if they could produce some more robust evidence. ‘Many felt that half an hour wasn’t going to do anything – it would just disrupt the school schedule,’ Owens recalls. She suggested that they collect data on the students’ sleep and mood before and after a three-month trial of the later start.
Owens was pleasantly surprised by the results. Just a 30-minute delay in starting school resulted in pupils getting an extra 45 minutes of sleep per night: ‘Anecdotally, they said that they felt so much better getting an extra half-hour of sleep that they were motivated to go to bed earlier and get even more,’ Owens says. ‘And they could afford to go to bed earlier because they were more efficient at getting their homework done.’
The percentage of students getting less than seven hours of sleep decreased from 34 per cent to just 7 per cent, while the proportion getting at least eight hours rose from 16 per cent to 55 per cent. The kids also rated themselves as less depressed and more motivated to participate in a variety of activities.21 But the thing that really swung it for Owens was the change in her own daughter, Grace. ‘She was like a different person,’ she says. ‘It was no longer a battle to get her up in the morning; she would be able to eat breakfast; and the start of the day was just pleasant, instead of torture for everybody.’
Owens changed her research focus and became involved in drawing up policy on school start times for the American Academy of Paediatrics, based on the best available evidence. In 2014, they issued a policy statement: starting school before 8.30 a.m. is a key modifiable contributor to insufficient sleep, as well as circadian rhythm disruption, in the adolescent population.22
But how late is late enough? Most British schools don’t start school until around 8.50 a.m., but one recent study concluded that most eighteen- and nineteen-year-olds don’t feel mentally sharp until much later, and therefore possibly shouldn’t start their studies until after 11 a.m. In a separate study, the same researchers tested whether moving the start time of an English comprehensive school from 8.50 a.m. to 10 a.m. made any difference to its thirteen- to sixteen-year-old pupils. Rates of absence due to illness fell dramatically following the change: whereas before they had been slightly above the national average, two years after the change they were down to half the national rate. Pupils’ school performance also improved: at baseline, things looked grim, with just 34 per cent of students gaining ‘good’ GCSE grades at age sixteen, compared to 56 per cent nationally. But after the introduction of 10 a.m. starts, this rose to 53 per cent.23
Meanwhile, one British sixth form – the independent Hampton Court House school on London’s southwest fringe – is starting lessons at 1.30 p.m. and finishing at 7 p.m., enabling students to have ‘more independence over how they structure their day’.
Even a 10 a.m. start would be difficult to impose in countries such as the US, where most adults also start work earlier than in Britain. It would require a change of mindset among parents – as well as a more flexible attitude by employers – but the data suggests that it would make a difference to many pupils.
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The tide may be turning in schools, but in the workplace, there’s still a way to go. An individual’s chronotype is based on his or her sleep behaviour on free days, and a simple way to define it is to look at when the mid-point of sleep occurs: if you fall asleep at midnight on weekends and wake up at 8 a.m., your mid-sleep time would be 4 a.m. Roenneberg has discovered that for 60 per cent of people, the mid-sleep time on free days is between 3.30 a.m. and 5.30 a.m. There are some earlier birds, but a greater proportion of the remainder sleep later than this.
Expecting people to wake at 6.30 a.m. and then to be mentally sharp when they arrive at work at 8 a.m. or 9 a.m. is therefore fighting against nature to some extent. Like physical performance, your mental skills peak and trough at various times throughout the day. Logical reasoning tends to peak between 10 a.m. and noon; problem-solving between noon and 2 p.m.; while mathematical calculations tend to be fastest around 9 p.m.24 We also experience a post-lunch dip in alertness and concentration between about 2 p.m. and 3 p.m. However, these are averages, so a lark’s peak in problem-solving may arrive several hours earlier than a night owl’s.
Research into this area is only just beginning, but managers with early-bird tendencies have been found to judge employees who start work later as less conscientious, and to rate their performance lower, compared to those who share such managers’ sleep preferences. ‘If your boss shows up at 7.30 a.m. and you walk in at 8.30 a.m., he thinks “we’ve already been working for an hour, and you’re going to work an hour less”; he doesn’t see that you will stay for an extra three hours after he goes home,’ says Stefan Volk, a management researcher at the University of Sydney Business School. ‘It also has to do with his mindset: because he is very productive in the morning, he assumes that’s the case for everybody, so he feels you are wasting time.’
Not only would a greater appreciation of these individual differences, and allowances for different schedules, help to level the playing field, it could boost workplace productivity, and employees’ health and happiness: ‘If you are forcing an evening person to show up at 7 a.m., all you have is a grumpy employee who sits there and drinks coffee, procrastinating until 9 a.m. because he simply can’t focus,’ says Volk.
Such an approach could create a more harmonious and morally sound workplace as well. Sleep deprivation robs glucose from the cerebral cortex, the brain region responsible for self-control. One study found that employees who got less than six hours of sleep per night were more likely to engage in unethical or deviant behaviour, such as falsifying receipts or making hurtful comments to their colleagues.25 Another found that the timing of unethical behaviour differs according to people’s sleep preferences:26 larks are more prone to behave unethically towards the end of the day, when they are growing tired, whereas night owls are more likely to behave badly in the morning.
Allowing staff to choose their work hours based on their individual sleep preferences is one solution then. But is it worth the potential disruption it might cause? In a recent study,27 American researchers piloted a three-month intervention at a global IT firm, which aimed to improve workers’ sleep and work–life balance, by helping them to move from a time-based to a more results-based office culture. Rather than judging colleagues on how they spent their time, workers were encouraged to work at whatever time or place they wanted, so long as they achieved specific results, such as delivering finished projects to customers.
Following its introduction, workers’ average sleep time increased by 8 minutes per night – adding up to almost an extra hour of sleep over the course of a week. But, perhaps more importantly, the number of times that people reported never or rarely feeling rested upon waking, went down. As one employee who previously had to get up at 4.30 a.m. in order to get an early start at work and avoid the evening rush hour put it: ‘If I’m working from home I don’t get up until 6.00 or 6.30 and I start working at 7.00 … I get more sleep than I’ve had in years.’
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In Bad Kissingen, Wieden’s current focus is on establishing a Centre for Chronobiology in the town, which would provide an academic hub for chronobiology research across Europe. The proponents of the Chronocity project hope that this will galvanise the town and lend authority to their efforts: ‘If we have a professor of chronobiology based here, who will go out into the community to give lectures and initiate research, it should be easier to open doors to hospitals and businesses and have a greater influence on health,’ says the mayor, Kay Blankenburg.
There have been some other victories as well. The Stadtbad, which oversees tourist and spa facilities in the town, now offers flexible working to its office staff; while Thorn Plöger, the manager of Bad Kissingen’s rehabilitation hospital, took the idea so seriously that, at one point, he adjusted all the hospital’s clocks, making some a little fast and some a little slow, in order to provoke reflection. ‘People are always so stressed about the time,’ he explains. ‘They would say, “it’s 9 o’clock, I must get my medicine”, or “I have a date at midday, so I must leave”; I told them, “take it slowly: entdecke die zeit”.’
Did they respond well, I ask?
‘No,’ he says, with a mischievous smile, ‘they said “you have to change the clocks back”.’
Plöger sighs and shakes his head. ‘Germany has a problem. People are always watching the clock.’ For the Chronocity initiative to work, he explains, it requires a more flexible mindset: one which says, it doesn’t matter when you start work, so long as you get the job done. It’s about internal time, not what the clock on the wall says.
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In February 2017, Plöger left the clinic to become manager of the Bavarian Rhön, a 480-square-mile area of rolling wild country, dominated by a set of extinct, dome-shaped volcanoes. Having picked up Wieden’s mantel and run with it, he is already planning the world’s first region that puts internal time at its forefront. At the heart of these efforts will be policies that promote the value of reducing light pollution (and, hopefully, persuade the Rhön’s towns and villages of the same), enabling people to sleep more easily and appreciate the spectacular night skies.
Similar seeds are germinating elsewhere, as people wake up to the fact that light does so much more than just enable us to see. The research for this book has taken me to many places, and introduced me to numerous people who, like Wieden, are agitating for a revolution in our attitudes towards light and sleep.
They have convinced me that it is possible to forge a healthier relationship with night and day without returning to a pre-industrial past, where the extremes of light and dark restricted our productivity and made it uncomfortable to live – even difficult to survive – at certain times of year.
We need to spend a greater proportion of our daytimes outdoors, to reap both the biological benefits of sunlight on our skin, and to realign our internal clockwork. However, it would be naïve to suggest that this is achievable for everyone all the time – sometimes we’re just too busy to take a walk around the block at lunchtime; it is impractical to walk or cycle to work; or it’s just not possible to eat breakfast next to a large east-facing window, bathed in bright morning light. So, we must also strive to find new and innovative ways of brightening our homes and workplaces – as well as dimming our lights in the evenings.
Already, lighting companies are tweaking indoor lighting to make it more like daylight, but in the future lighting may be tailored to the individual: sensors will detect how much light people have been exposed to over the previous 24 hours, possibly in connection with software used to track their sleeping patterns. The lighting at home and at work will then be adjusted to optimise an individual’s circadian rhythms and keep them entrained to the sun.
Similarly, new and better ways of keeping tabs on people’s internal rhythms will enable drugs to be given when they’re most likely to be effective – or maybe become active only once an internal clock-hand passes a certain hour.
And although we haven’t yet found a solution to the problem of shift work, it’s clear that we should be doing everything we can to minimise circadian misalignment: this means trying to regularise our schedules as well as going to bed early enough to ensure adequate sleep.
We spawned from a revolving planet, itself shaped by starlight. And although we create our own electric stars to light the night, our biology remains tethered to a monarch mightier than them all: our sun.