In a matter of days, most Canadians will change their clocks from Daylight Saving Time back to Standard Time.Andrey Popov/iStockPhoto / Getty Images
The Sleep Whisperer is a series of columns offering insights and advice about sleep health. It is not a substitute for seeking professional medical care.
The debate over Daylight Savings Time has been raging for years and is still going strong. Recently, Liberal MP Marie-France Lalonde introduced a private member’s bill calling on the federal government to hold a pan-Canadian conference to discuss abandoning the practice – an initiative I, and most of my colleagues in the sleep and chronobiology field, endorse.
Yet, in a matter of days, most Canadians will change their clocks from Daylight Saving Time (DST) back to Standard Time (ST). Pushing clocks forward by an hour in the spring and then winding them back an hour in the fall is more than just a minor inconvenience – it has many effects on health, safety and performance.
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Here is an overview of what we know, why it matters and what you can do to alleviate the impacts.
The biological toll of shifting clocks
Many people are already aware that changing the clocks can interfere with our sleep. For instance, when we “spring forward” to DST each March, we suddenly lose an hour of sleep – an added strain on top of the chronic sleep deprivation many Canadians already experience.
Importantly, this shift also delays our exposure to morning sunlight, making it harder to wake up. The extended evening light also pushes bedtimes later, even though we tend to get up at the same time. This curtails and weakens sleep, not only on the day of the time change but in the following weeks. In contrast, the return to ST each November allows people to regain an hour of sleep while making it easier to wake up and to perform better in the mornings.
What fewer people realize is that there are also health impacts beyond sleep. Why? Hidden deep in your organs, tissues and even cells, is a complex network of biological clocks that regulates most body processes – from hormone release to metabolism, blood pressure and immune functions. For most people, these clocks run on a period slightly longer than 24 hours, which means that our biological rhythms tend to spontaneously drift away. Under normal conditions, the natural cycle of the sun constantly realigns the internal timing of our clocks closer to 24 hours. However, when we force an artificial time change, we switch our light exposure away from solar time, wrecking the delicate adjustment mechanisms in our biological clocks.
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You may not notice it, but each time we change the time it takes several days or even weeks, for your body to fully reset. Certain groups of people are more affected than others, including older adults, children and teenagers, and those living with chronic health conditions.
What the research has shown
Research has shown that shifting to DST in the spring has more negative effects on health than the switch back to ST in the fall. The transition to DST is associated with increases in heart attacks, strokes, pregnancy complications and weight issues, to name a few. In fact, a recent study found that abolishing DST and maintaining permanent ST would decrease the prevalence of obesity and stroke. There are also more roadside and workplace accidents around the spring change to DST, and productivity at work and at school suffers as well. In addition, switching to DST has been found to worsen mood and mental well-being, driving higher rates of depression and even suicide.
However, the switch to ST in the fall has also been found to have negative impacts on mental health. For example, research unveiled an increase in substance use in adult males. And a Danish study found the transition to ST was associated with an 11 per cent increase in depression episodes.
The period leading up to the fall time change can also be difficult. Living at a northern latitude means our days in Canada naturally grow shorter and darker during the fall. Because we carry DST until November, our clocks remain artificially advanced at a critical time of year when morning light is already getting scarcer. This worsens the seasonal slump many people feel until the return to ST.
What you can do to help
What if we prioritized health for all and put a halt to this unnecessary burden? That’s a question many experts – myself included – are increasingly asking. Recommendations from sleep and chronobiology organizations in Canada and across the world concur that permanent standard time would bring benefits by better aligning our daily schedules with the natural cycle of the sun.
Until policy catches up with the growing body of evidence, these practices can help reduce the strain of time change during the fall transition:
Shift sleep routines gradually in the days leading up to time change. For instance, in the last week of October, ahead of this year’s November 2 time change, you could start progressively delaying your bedtime and wake up time by about 15 minutes every few days to avoid an abrupt shift. Maintain consistent schedules for eating, exercise and sleep during the transition period, as this helps anchor the timing of your biological clock.If you feel the need to nap, keep it brief – no more than 20 to 30 minutes – and nap early in the day. Longer or late-afternoon naps can reduce your natural sleep drive, making it harder to fall asleep and stay asleep at night.Adding to the effect of time change in the fall is the start of winter blues for many people. Consider the feelings of those around you who may be struggling, even if you are not. Showing some empathy and support in these transition periods can make a big difference.
Dr. Rébecca Robillard, PhD, is a clinical neuropsychologist and associate professor at the School of Psychology at the University of Ottawa. She also leads clinical sleep research at The Royal mental health hospital. Robillard’s main area of work focuses on interactions between mental health, the sleeping brain and the sleeping heart. She co-chairs the Canadian Sleep Research Consortium, a national hub of sleep scientists and clinicians.