The Sleep Whisperer is a new series of columns offering insights and advice about sleep health. It is not a substitute for seeking professional medical care.
On March 14, advocates for better sleep health will mark World Sleep Day. Why is a day of recognition needed for sleep? Healthy lifestyle practices often focus on exercise and nutrition and tend to neglect sleep – despite its impacts on health and overall well-being.
Perhaps not surprisingly, many people report they are not getting enough sleep. A national survey led by the Canadian Sleep Research Consortium, which I co-direct, and published in the Sleep Medicine journal in 2024, found that nearly a quarter of Canadians are dissatisfied with their sleep. This is why our national hub of sleep researchers has come together to share information about sleep and raise awareness about the importance of sleep health – including an interactive campaign called Week for Better Sleep.
How do we get a better night’s rest? Before tackling that question, it helps to understand how sleep works. During sleep, our brain enters multiple different states, which restore, heal, grow, reprocess, and strengthen our bodies and minds. Sleep health is not just about quantity, but also about unlocking the diverse dimensions of sleep.
A typical journey through sleep stages
During the night, we cycle through four sleep stages, which activate processes that enhance mental and physical functions.
As we drift into Stage 1 sleep, our respiration, heart rate and brain activity slow down. When we reach Stage 2 sleep, two distinct features emerge: short bursts of rapid brain activity, called sleep spindles, and isolated large slow waves, called K-complexes. These features serve important functions. Sleep spindles reinforce new memories; the more spindles your brain produces, the more you will remember what you have learned the previous day. In fact, your brain is so kind that it will even produce more spindles after busy days with lots to learn. K-complexes, for their part, are the gatekeepers of sleep. Your cat jumping on the bed may trigger a K-complex in your brain. This enables you to register that something happened in your environment and assess that there is no threat so you can stay asleep.
Stage 3 sleep – the deepest sleep – generates big slow waves of brain activity on the electroencephalogram (EEG). Far from a brain-dead state, deep sleep looks like a sea storm. It kind of acts like one as well. It increases the flow of liquid in the brain to flush away the neurotoxins we accumulated during the hours we spent awake. This leaves our brain cells shiny and sharp for the next day. Deep sleep also helps repair the wear and tear our body accumulated during the day, strengthen bones and muscles, reduce fat mass, boost the immune system and improve cardiovascular functions.
During REM sleep (also known as paradoxical sleep), brain activity is very similar to what we see during waking hours, which creates the experience of vivid dreams. However, most of our body is paralyzed, except the eyes, which do repeated jerky movements. REM sleep helps with emotional regulation by lowering the affective tone of what we experienced during the day. It also boosts creative thinking and certain memory types. For example, if you are working on your skiing moves this winter, REM sleep reactivates key parts of your brain to ‘replay’ your challenging runs so you can continue practicing overnight.
Ensure productive nights ahead with the 6 core domains of sleep health
How can you optimize sleep’s wonders? An emerging view of sleep health highlights six core domains, which have been linked to good health and well-being.
Duration: Guidelines suggest that adults should sleep six to eight hours a night. Although these guidelines are helpful to get a sense of what is ‘typical’, sleep needs vary considerably across people (notably determined by genetics). What matters most is we give our body as much sleep as it needs.
Continuity: Should we fall asleep as soon as our head hits the pillow and stay asleep until the next morning? Not necessarily. Falling asleep too quickly may be a sign that something is off (e.g. you may not be getting enough sleep). Also, it is normal to wake up during the night. Yet, if you regularly spend more than 30 minutes awake at night, something could be weakening your sleep. This could be too much napping, going to bed too early, or even an insufficient winding down buffer before bedtime.
Timing: The healthiest sleep aligns as much as possible with the time when our body temperature, heart rate, hormones, and metabolism are in ‘sleep mode’. This time is set by our biological clock, which runs early for some and late for others. If your schedule allows, the best approach is to set your sleep schedule according to your own biological rhythms, when it feels most natural to fall asleep and wake up.
Alertness: The quality of our wakefulness during the day and our ability to stay alert while awake are good barometers for healthy sleep. If you feel fairly energetic and focused during the day, you are likely getting enough zzzs.
Regularity: Keeping a regular sleep schedule maximizes your chances of getting enough good quality sleep while strengthening your biological clock.
Satisfaction: Since we cannot get perfect sleep all the time, setting realistic expectations is key to avoid drowning in unhelpful preoccupations about sleep. Yet, if you regularly feel you have poor sleep, it may be a good idea to talk to your doctor to see if you might benefit from a sleep test and/or sleep interventions.
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. Dr. 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.
