Modern life is 24-7, but there may be negative consequences to defying our body’s internal clock
It started with rats.
In 1999, third-year psychology student Jessa Gamble was working as a research assistant in a lab at the University of Toronto. Part of her work involved observing caged rats being kept in darkness. At first, the rodents’ actions appeared random, whether they were drinking water, running on a wheel or standing on their hind feet to take a look around.
But as Gamble writes in her fascinating book, The Siesta and the Midnight Sun (which will be published in October), an instrument hooked up to the cage revealed that the rats were repeating their actions at precise times, day in and day out. No question about it: the data were “spookily identical.”
Except for one thing. While following a 24-hour cycle, the rats would start their routines just a few minutes later each day, with some starting a little later than others. In the wild, daylight and its disappearance rigidly structures rat behaviour; but even in darkness, their internal clocks did the job almost as well.
Gamble’s experiences at U of T led to her much broader study of what is most commonly known as circadian rhythms. Her book reveals how all living organisms – plant, animal and human – time their functions to take place at specific points during Earth’s 24-hour rotational cycle.
The planet’s natural phases of light and dark give order to our lives, and our behavioural and physical processes faithfully respond to the Earth’s cycle. This means that there are, in fact, optimal times to eat, sleep, think, exercise, reproduce and take medicine. As Gamble, 32, points out in her book, scientists now believe that we disregard those times at our peril.
The word circadian refers to a daily cycle, but Gamble’s study takes in seasonal rhythms as well. These biological oscillations “link us to the rest of the world, and ground us in this Darwinian realization that we are part of a continuum,” the science reporter tells me from her home in Yellowknife. “We don’t perceive the rotation of the planet. We forget that we’re part of this giant universe. But we are part of it, and down to the cellular level we’re responding to that reality.”
The science of circadian rhythms (also known as chronobiology) is now half a century old. While that’s a long time to have known about the internal clock’s existence, many experts believe we haven’t paid nearly enough attention to what it is telling us.
Jet travel, shift work and medication are just some of the forces playing havoc with the proper functioning of our bodies. Because of globalization, we’re also more inclined to share timetables – to our possible detriment. As Martin Ralph, a psychologist and the director of U of T’s Centre for Biological Timing and Cognition, puts it: “Everything is built to work over 24-hour intervals. If you disturb those rhythms, you could get chronic disease.”
Anyone who has experienced jet lag knows it can derail your natural order and leave you temporarily weak and groggy. Gamble certainly courted grogginess while researching her accessible, deliciously factoid-crammed book. Travelling from Japan to Spain, England, California and Canada’s Far North, she discovered her chosen subject was being studied throughout the world.
The burgeoning field is also highly interdisciplinary. As Gamble shows, chronobiology is now being studied by anthropologists, astronomers, medical doctors, psychologists and botanists, to name just a few. And it’s not only the province of scientists. Athletes and executives, new mothers and nightclub bouncers – anyone victimized by the external clock’s tyranny – find a place in Gamble’s first book.
Born in Oxford, England, Gamble received a bachelor of science in psychology from U of T in 2003 while attending Victoria University. But she balked at killing laboratory animals – “though I’m still really interested in the research that comes out of that” – and ultimately chose to report on science instead of practising it. “Science communication is a bit of a mission for me,” says Gamble. “I really want to make science accessible to the public, as they are paying for much of it. And I think they deserve to have that information.”
Gamble, who came to Canada as a preteen, was an aspiring journalist who kicked around the Toronto magazine world upon graduation. She co-founded a publication on underground culture called Neksis (“We drove it into the ground,” she says), and interned at magazines such as Canadian Geographic and the now-defunct Shift and Elm Street. But the grinding competitiveness of Toronto media started to wear her down, and she soon found herself travelling very far afield. “I got a job at Up Here magazine, which covers all of Canada’s Far North,” says Gamble, who still bears a slight English accent from her childhood. “That allowed me to travel extensively and cover a wide range of things, though I ended up focusing on science.” In 2007, her account of life at the Eureka High Arctic Weather Station earned her a Science and Society Journalism Award from the Canadian Science Writers’ Association.
A Yellowknife resident for the past five years, Gamble is well acquainted with one of the more harmful effects of altering your circadian rhythm: seasonal affective disorder. Did long, dark winters on the 62nd parallel inspire her research? “It absolutely did,” she says. Gamble doesn’t suffer from SAD, but she reacts to the season like many others in the region: “I experienced a real drag in the winters, and I still do; it’s not something you’re cured of. But I got really interested when I started visiting northern communities and learned that in living memory, people had been pursuing a totally different lifestyle in conjunction with this 24-hour darkness. It was a way more seasonal lifestyle, with different activities slotted into the different seasons.”
Aboriginal northern peoples were once fully able to work in concert with this cycle of dark and light. “Elders in northern Canada recall that summers were a time of almost manic hunting and working,” Gamble writes in Siesta, while “the starlit winters were for staying indoors, eating from the meat cache and enjoying one’s family.”
Now, however, northern people are inextricably linked to their fellow citizens in the south because they share schedules and resources. This resulted in northerners increasingly being forced to accommodate themselves to southern timetables, something Gamble calls “circadian imperialism.” Ralph points out that children in Nunavut, for example, start school at the same time as their southern peers – but up there it’s in darkness, when their bodies are still releasing vast quantities of melatonin, a sleep hormone. “It’s hard to imagine people will perform that well, and they don’t,” he says. Ralph thinks that in the long term, this “desynchronization” could be problematic.
The northerner’s predicament is comparable to “permanent jet lag,” says Ralph. His animal studies have shown that shorter lifespans, obesity and cardiovascular disease are some of the potential results if this bodily disruption isn’t curbed. He suspects that certain physical and mental-health problems that have long plagued the northern communities he studies (such as Iqaluit, Nunavut) may be partially attributable to this phenomenon.
Indeed, the human body appears to be an orchestra that plays the same symphony each day. Its component instruments pipe up at predictable intervals, play their part, then move on. A clump of cells in the brain’s hypothalamus, known as the suprachiasmatic nucleus, acts as the conductor, and it does its job well. Body temperature, hormone production, cellular division and brainwave activity – everything inside us is subject to patterns.
On average, a person’s cognition peaks in the morning, while lung function is optimal in the early evening. This, too, appears to be the best time to exercise: it’s when the perception of exertion is at its lowest, and when athletes appear most able to break world records. Further, “every hour and a half, a little wave of sleepiness comes, and then it passes,” Gamble says. “That’s a good thing to know if you’re feeling tired, and you think it means you have to go to bed.”
Digestive processes have their own timetables, too. A drop in energy levels after lunch leads to a phenomenon called the post-prandial dip – traditionally medicated in Spain with a siesta, the midday nap. (The Spanish government scrapped this idea for its employees in 2006, citing, among its concerns, the need for wakeful workers in a globalized world.) Bowels tend to be active in the morning – by way of proof, Gamble cites the example of New York City’s “Big Flush,” which reliably occurs each morning between 8 and 9. At this time, 150-million gallons of human waste sluice through the city’s sewage system; at other times, the average is 70-million gallons.
These optimal functioning times are based on averages, of course. There are some individuals whose clocks are just . . . off. Many of us, for example, describe ourselves as “morning people” or “nighthawks.” In fact, owning one of these rigidly fixed identities, known as chronotypes, isn’t common. But Gamble says both “larks” and “owls” really exist. If you’re the latter, she says, “then all of your rhythms are probably a little bit later. So that’s why I hesitate to put down that at 10:30 in the morning you’re going to be at your best, because that’s going to be different for larks than for owls.” Accordingly, an owl-child performing poorly at school might be diagnosed as having attention deficit disorder. But it’s worth asking: is the child merely being forced to contravene the rules of her internal clock?
Some medical doctors are now taking circadian science very seriously. It’s becoming more clear that the time of day when a medication is taken has a direct bearing on its efficacy. Recently, researchers at U of T and the University of Guelph found that mice with high blood pressure experienced improved heart structure and function when given angiotensin-converting enzyme (ACE) inhibitors at night. When taken in the morning, however, the medication was no better than a placebo.
The research of medical oncologist Georg Bjarnason at Toronto’s Odette Cancer Centre/Sunnybrook Health Sciences Centre has focused on how circadian rhythms affect the timing of cancer treatment. Working with patients who have head and neck cancers, the U of T associate professor has shown that radiation in the morning is less toxic than when it is administered in the afternoon. In a clinical trial setting, chronotherapy (along with chemotherapy drugs) has also demonstrated positive results for men with metastatic colorectal cancer and children with acute lymphoblastic leukemia. In addition, says Dr. Bjarnason, “we know that cancer patients on therapy who have an abnormal sleep pattern have poorer survival.”
Sleep. It’s the bodily function that comes up most in any discussion of biological rhythms. The well-worn mantra is that we need an eight-hour run of it or bust; but is this really true? Gamble suggests that we should be more flexible in our search for the perfect slumber. She cites the work of American psychiatrist Thomas Wehr, who conducted a four-week study in the 1990s in which the subjects, like the lab rats she once observed, were deprived of artificial light for some 14 hours in each 24-hour period.
“They slept for a lot longer than usual, but in the middle they woke up and had two hours of quiet contemplation in bed,” says Gamble. “During that time, they had a surge of prolactin – a hormone we use in lactation and sex, but that doesn’t surge during an unbroken eight-hour sleep. People who experienced that ‘anti-nap’ during the night said that the next day, they experienced true wakefulness for the first time.”
Gamble notes that some very famous and accomplished people have been able to work “polyphasic” sleep into their working lives. For a time, American designer Buckminster Fuller only ever catnapped, scattering four half-hour kips throughout the day. And Gamble says that even during the Second World War, Winston Churchill managed to take a midday nap – in pyjamas, no less – prior to waking and working until 3 a.m, and then rising at 8. “By all accounts, he was energetic and hard to keep up with,” she writes.
Night waking is something that bothers us enormously; many routinely ingest sleeping pills to stamp it out. But as Wehr has written: “Waking up after a couple of hours may not be insomnia. It may be normal sleep.” In her book, Gamble alludes to historical evidence (references to “second” and “morning” sleeps) suggesting that people in earlier centuries regarded night waking as normal – a time for praying, meditating or communing with one’s spouse.
As the science of biological rhythms catches on, it is not hard to imagine the marketing potential attached to it: one foresees a spate of quickie books with names such as The Circadian Diet and Awake at Last. But Gamble considers herself a science writer, not a purveyor of self-help.
Still, at last year’s TEDGlobal (Technology, Entertainment, Design) conference in Oxford, England, Gamble gave a talk on biphasic sleep and received a barrage of attention from audience members keen on self-improvement. “I got a lot of response from people saying, OK, help me achieve this, I’m really interested. But being prescriptive is the furthest thing from my mind. I’m so much more interested in the way things are than the way things should be. I’m just curious about the way everyone manipulates the biological imperatives and tries to get around them, but I’m not trying to change things. I don’t know what to say to these people!” she laughs.
Still, Gamble thinks that becoming aware of one’s own personal rhythms is a very good idea, and she is not averse to experimenting on herself. One way she has done this – she swears it works – is by fighting the development of jet lag when she travels, with the help of a smartphone application. Her Virgin Atlantic Jet Lag Fighter offers a simple program: start shifting waking and sleep times three days before the trip, get a good dose of natural light in the afternoon and exercise in the early evening.
We tend to tolerate jet lag as a normal consequence of international flight, but Gamble thinks we shouldn’t. “For someone who travels regularly it’s worth calculating what effect your sleeping schedule is going to have, especially when there are critical decisions to be made on the other end. If it’s the middle of the night in your internal time, you’re doomed.” Amusingly, her book notes that at various points during its history, Monday Night Football’s 9 p.m. EST kickoff time allowed western players an advantage. They were consistently able to derive the benefits of an early-evening performance time (the proof is in the record books).
Technology such as the Jet Lag Fighter is designed to “abnormalize” a typical day, the better to maximize activity. But scientists have also done the reverse. Gamble cites a recent example, which occurred when a group of Chilean miners were trapped underground in the summer of 2010. The miners were instructed by hastily flown-in NASA experts to divide their living area into three parts: a brightly lit waking area, a darkened sleeping area and an in-between work area. They were also given vitamin D supplements to compensate for the lack of sunlight, and told to exercise at precise times. “Their triumphant return to the surface after two months led to talk of lucrative film and book contracts,” Gamble writes, “but the field of circadian rhythms is also indebted to them for a rare, real-world demonstration of circadian functioning in a totally artificial environment.”
Gamble is aware that, given the demands of modern life, it is practically impossible to live in complete sync with our clocks. As the mother of a two-year-old, she has learned what it’s like to care for a tiny creature whose suprachiasmatic nucleus has yet to develop. It’s inescapably wearying, of course – and right now there’s no app for that.
Still, she and a growing phalanx of scientists offer convincing proof: any steps we can take to better link our behaviour to our bodies may lead to improved health and longevity. It’s a line of inquiry that will make us more sympathetic to our environment, too, as we become more aware that every living thing contains a splendid orchestra within it, perfectly timed and impeccably tuned.
“You want to stop people on the street and say, ‘Have you heard about this? This is like the craziest thing ever!’” exults Gamble, ever the optimistic young science journalist. “It’s a mystery to me why we haven’t talked more about it. I hope, in my small way, that I’m contributing to changing that.”
Cynthia Macdonald (BA 1986 St. Michael’s) is a writer in Toronto. She profiled Chris Spence, the Toronto District School Board’s director of education, in the Winter 2011 issue.
Watch a BBC presentation about the body’s internal clock