Why we should fol­low the sun, not the clock

The Guardian - Journal - - Front page - By Linda Ged­des

Be­tween day­light sav­ing and oblig­a­tory early starts, we live at the mercy of ‘of­fi­cial’ time – and many of us feel per­ma­nently out of sync. Bi­ol­o­gists say we should be watch­ing the sun rather than the clock

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.

Lo­cated in the sparsely pop­u­lated re­gion of Lower Fran­co­nia in Bavaria, Bad Kissin­gen was once 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 were re­puted to cure all man­ner of ills. To­day,

Bad Kissin­gen has re­branded it­self as the world’s first ChronoCity – a place where in­ter­nal time is as im­por­tant as ex­ter­nal time, and sleep is sacro­sanct.

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 clock twice a year be­cause of day­light sav­ing time. The ques­tion that the idea of the “ChronoCity” raises is what changes could so­ci­ety make to bet­ter ac­com­mo­date our body clocks?

Michael Wieden, Bad Kissin­gen’s busi­ness man­ager, came up with the ChronoCity con­cept 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 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 of launch­ing 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 be ed­u­cated out­doors where pos­si­ble, and ex­am­i­na­tions not con­ducted in the morn­ings; busi­nesses should be en­cour­aged to of­fer flex­itime, al­low­ing peo­ple 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 place in the world to

“re­alise sci­en­tific field stud­ies in a wider con­text”.

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.

Since 1884, the world has been sub­di­vided

into 24 time zones, all re­fer­ring to the lon­gi­tu­di­nal merid­ian that crosses the Green­wich ob­ser­va­tory in London, hence the name Green­wich Mean Time (GMT). 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.

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% of global elec­tric­ity con­sump­tion and ap­prox­i­mately 6% of world­wide car­bon diox­ide emis­sions.

How­ever, it wasn’t un­til 1907 that an English­man called Wil­liam Wil­lett self-pub­lished a pam­phlet, The Waste of Day­light. Wil­lett be­lieved that align­ing work hours closer to sun­rise (at least in cities) might en­cour­age peo­ple to par­tic­i­pate in more out­door recre­ation, en­hanc­ing their phys­i­cal well­be­ing, and might keep them out of pubs, re­duce in­dus­trial en­ergy con­sump­tion and fa­cil­i­tate mil­i­tary train­ing in the evenings.

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”.

There was a sig­nif­i­cant down­side, how­ever, as 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

Our bi­ol­ogy is teth­ered to the sun, but the time is set by a tan­gled web of po­lit­i­cal and his­tor­i­cal fac­tors

worker will be some­what damp­ened”.

By mov­ing the clocks for­wards each spring and back­wards each au­tumn, we are cre­at­ing a form of

“so­cial jet­lag”, to use the term coined by the Ger­man chrono­bi­ol­o­gist Till Roen­neberg to de­scribe the gap be­tween our in­di­vid­ual body clock and the ex­ter­nal clocks and tim­ings that rule our lives. One study of US high-school stu­dents – a pop­u­la­tion that is al­ready sleep­de­prived – sug­gested that their sleep was cur­tailed by 32 min­utes per night dur­ing the week fol­low­ing the spring clock change. Maths and sci­ence test scores fall in the week fol­low­ing the start of DST among young ado­les­cents, while an­other study found lower an­nual scores for the SAT tests, which are used to de­cide univer­sity ad­mis­sions, among US coun­ties that ob­serve DST, com­pared to those that don’t.

In adults, the tran­si­tion to sum­mer time and the sleep de­pri­va­tion it causes has been as­so­ci­ated with 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.

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 Roen­neberg, the chrono­bi­ol­o­gist, who also sup­ports the scrap­ping of the bian­nual 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 Navajo Na­tion, which is largely in­side its bor­ders, does. (The Hopi Reser­va­tion, which is sur­rounded by the Navajo Na­tion, fol­lows the rest of Ari­zona in re­main­ing on win­ter time.)

In the end, the Bad Kissin­gen town coun­cil de­feated the mo­tion about be­com­ing DST-free. But even if the town isn’t ready to be­come a poster child for the an­tiDST 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 jet­lag caused by the time shift. The Euro­pean com­mis­sion also re­cently pro­posed abol­ish­ing DST – al­though it re­quires sup­port from the 28 na­tional govern­ments and MEPs be­fore any­thing changes. Mean­while, in south­ern Eng­land many would like to see the en­tire coun­try shifted per­ma­nently for­ward into Cen­tral Euro­pean Time, given that, in Britain, the an­nual chang­ing of clocks back to win­ter time means that it gets dark as early as 4pm 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 four min­utes to pass over each of them, which means that the sun rises 36 min­utes ear­lier at its east­ern bor­der than at 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 – their in­nate propen­sity to sleep at a par­tic­u­lar time – is shack­led to sun­rise. On av­er­age, Ger­mans wake up four 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. A sim­i­lar pat­tern has been doc­u­mented in the US, where those liv­ing on the east­ern edge of its time zones get up ear­lier 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 – 10pm is in fact 7.30pm ac­cord­ing to their in­ter­nal time, which is set by the 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 jet­lag even worse. And in mid-De­cem­ber, a switch to CET would mean that the sun would rise in London at 9am, and in Glas­gow at 9.40am. Many of­fice work­ers would be ar­riv­ing at their desks while it was still dark out­side. The sun would then set at 5pm 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. Sergei Kalash­nikov, the chair of the State Duma health com­mit­tee, claimed that the switch con­demned

Rus­sians to in­creased stress and worsening health, be­cause of hav­ing to travel to work or to 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.

There are few mem­bers of so­ci­ety who more ob­vi­ously find it hard to con­form to its early-bird de­mands 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 10 to 18. Here, a group of older stu­dents cre­ated a ques­tion­naire and can­vassed their fel­low pupils about whether it would be de­sir­able to start school at 9am rather than 8am: the ma­jor­ity said it would. They also chrono­typed the en­tire school and cal­cu­lated the amount of so­cial jet­lag its pupils were suffering from each week. Ap­prox­i­mately 40%

were ex­pe­ri­enc­ing two to four hours of so­cial jet­lag, while a fur­ther 10% were con­tend­ing with four to six hours – equiv­a­lent to fly­ing from Ber­lin to Bangkok and back – each week.

Teenagers are at greater risk of so­cial jet­lag than adults 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.

Teenagers’ later chrono­type also means that their nat­u­ral peaks in log­i­cal rea­son­ing and alert­ness oc­cur later than they do in adults. In one study, Cana­dian re­searchers com­pared the cog­ni­tive per­for­mance of teenagers and adults dur­ing the mid-morn­ing, and again, mid-af­ter­noon. The teens’ scores im­proved by 10% in the af­ter­noon, whereas the adults’ scores de­te­ri­o­rated by 7%.

One strat­egy for deal­ing with this is­sue is to de­lay school start times and al­low teenagers to sleep for longer in the morn­ings. The US 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, in the late 1990s, sev­eral high schools in the Min­neapo­lis sub­urb of

Ed­ina changed their start time from 7.20am to 8.30am. 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. Stu­dents said that they felt less tired dur­ing the day, while teach­ers re­ported that the chil­dren seemed more en­gaged and fo­cused. School at­ten­dance also im­proved.

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. When Ju­dith Owens, a pae­di­a­tri­cian with a par­tic­u­lar in­ter­est in sleep medicine, was called in by her daugh­ter’s high school to talk to staff about the po­ten­tial ben­e­fits of start­ing school 30 min­utes later, she 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. The per­cent­age of stu­dents get­ting less than seven hours of sleep de­creased from 34% to just 7%. The kids also rated them­selves as more mo­ti­vated to par­tic­i­pate in a va­ri­ety of ac­tiv­i­ties. 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 Pe­di­atrics, based on the best avail­able ev­i­dence. In 2014, they is­sued a pol­icy state­ment: start­ing school be­fore 8.30am is a key mod­i­fi­able con­trib­u­tor to in­suf­fi­cient sleep, as well as cir­ca­dian rhythm dis­rup­tion, in the ado­les­cent pop­u­la­tion.

But if school should start later in the day, what time would be best? Most Bri­tish stu­dents don’t start school un­til around 8.50am, but one re­cent study con­cluded that most 18- and 19-year-olds don’t feel men­tally sharp un­til much later, and there­fore pos­si­bly shouldn’t start their stud­ies un­til af­ter 11am. In a sep­a­rate study, the same re­searchers tested whether mov­ing the start time of an English com­pre­hen­sive school from 8.50am to 10am made any dif­fer­ence to its 13- to 16-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.

Even a 10am 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.

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 their 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 at week­ends and wake up at 8am, your mid-sleep time would be 4am. Roen­neberg has dis­cov­ered that for 60% of peo­ple, the mid-sleep time on free days is be­tween 3.30am and 5.30am.

Ex­pect­ing peo­ple to wake at 6.30am and then to be men­tally sharp when they ar­rive at work at 8am or 9am in­volves some­thing of a fight against na­ture. Like phys­i­cal per­for­mance, your men­tal skills peak and trough at var­i­ous times through­out the day. Log­i­cal rea­son­ing tends to peak be­tween 10am and noon; prob­lem-solv­ing be­tween noon and 2pm; while math­e­mat­i­cal cal­cu­la­tions tend to be fastest around 9pm. We also ex­pe­ri­ence a post-lunch dip in alert­ness and con­cen­tra­tion be­tween about 2pm and 3pm. How­ever, these are av­er­ages, so an early riser’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. 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 7am, all you have is a grumpy em­ployee who sits there and drinks cof­fee, pro­cras­ti­nat­ing un­til 9am be­cause he sim­ply can’t fo­cus,” says Ste­fan Volk, a man­age­ment re­searcher at the Univer­sity of Syd­ney Busi­ness School.

Al­low­ing staff to choose their work hours based on their in­di­vid­ual sleep preferences is one so­lu­tion. But is it worth the po­ten­tial dis­rup­tion it might cause? In a re­cent study, Amer­i­can re­searchers pi­loted a three­month 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 eight 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 4.30am 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 or 6.30 and I start work­ing at 7 … I get more sleep than I’ve had in years.”

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: “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 that 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. • Adapted from Chas­ing the Sun by Linda Ged­des, pub­lished by Well­come Col­lec­tion and Pro­file Books and avail­able at guardian­book­shop.com

Den­nis Ver­nooij I LLUSTRATIONS

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