We’re at the strangest place culturally when it comes to sleep. We’ve never been so obsessed: We buy smart watches and Oura rings to track our sleep quality relentlessly every night; we pony up for the latest, greatest, smartest mattress; we gobble sleep tonics, CBD (and yes, Ambien and Xanax) and “sleep ice cream”; we pay to crawl into nap pods; and we travel far just to bed down at sleep retreats. The wellness world and Silicon Valley have unleashed every device and solution seemingly imaginable, from sleep robots that cuddle us and control our breathing[1] to pricey sleep supplement subscription plans. We have made complex sleep shrines of our (now often desexualized) bedrooms, banishing our partners through “sleep divorces.” This has created an entire “sleep economy” set to reach $585 billion by 2024[2].

Sleep has suddenly become such an over-the-top wellness trend that the media has begun mocking our agonizing over it, noting the rise of orthosomnia[3], a condition where anxiety over sleep tracking causes sleep problems. When, in human history, have we ached so much for sleep and unconsciousness? Why, with an avalanche of sleep solutions and a newly sleep-obsessed culture, do we remain in a sleepless epidemic, with around one in three of us sleeping badly and one in 10 having regular insomnia?

The reason is that most of these generic sleep solutions, and our modern lives, defy the basic facts of circadian biology. Humans evolved to be highly sensitive to the 24-hour solar cycle and super-regular exposure to natural light and dark. Nearly all organisms, including humans, have internal daily clocks (circadian rhythms) that control almost every biological system in our bodies, from our sleep-wake cycles and mood and performance patterns to our metabolic, immune and reproductive systems. The bedrock of circadian science is that exposure to regular light-dark cycles provides the daily “time cues” needed to reset our circadian clocks every single day, and not only determines how well we sleep but our very cellular health. We need the sun’s bright blue light in the day to be alert and active, and we need dark to kick-start our brain’s sleep mode and recovery.

Humans today, however, have never been exposed to so much disruption to their circadian rhythms, such as the glaring disconnect between natural solar time and our social “clocks.” We’re taking in light and dark in historically whacked-out, unnatural ways. We blast our eyes after dusk with blue-enriched light from ever-brighter, addictive screens, tricking our brains into thinking it’s still daytime: Netflix binging, checking social media until we pass out. Work increasingly doesn’t conform to solar time. While 20 percent of people are nightshift workers, reversing their day-night behavior, gig work is also soaring: Fifty percent of the world’s workforce works remotely at least half the week[4], part of the creeping “always-on” work culture that encourages us to further disconnect from natural cycles. We have a shrinking global world: more airline travel so more circadian disruptions such as jet lag and global conference calls at all hours of the night. Ours is a 24/7 culture (from gyms to supermarkets); light pollution increasingly floods our skies at night; and we’re tied to desks, deprived of natural sunlight in the day. Never before have human environments been such a “lightmare[5].”

As Dr. Steven Lockley, associate professor of medicine at Harvard and one of the world’s top experts on circadian rhythms and sleep, puts it: “The absolute key to healthy sleep and circadian rhythms is stable, regularly-timed daily light and dark exposure—our natural daily time cues. Sleep negates light input to the brain, and so keeping a regular sleep pattern will also help maintain regular light-dark exposure. After dusk, when natural light disappears, we must minimize the negative impact of man-made light. In the day, we have evolved to be in the light, ideally sunlight, but if not, high-quality blue-enriched indoor light. Period. Given that most of our body systems express circadian rhythms, ensuring proper alignment of our internal circadian clocks, starting with the management of lighting, will have major impacts on human health.”

While we’ve been obsessed with sleep, and trying to get more of it with smart pillows and tonics, it’s the timing of sleep that is absolutely key to getting high-quality, restorative sleep. This means sleeping at the right circadian time, and the only solutions that can actually reset circadian rhythms have LIGHT at the center of them.

So, we predict a major shift in wellness: less focus on all the generic sleep solutions and a keen new focus on circadian health optimization for not only sleep but for all the brain and body systems that are controlled by the circadian clock. It means that the TIMING of biology will become something we need to measure and manage, and light will be a central part of any solution.

Dr. Lockley predicts: “Circadian health optimization—incorporating the type and timing of light—will become more important than ‘sleep’ in health and wellness within the next few years. Medical and technological solutions that will help us realign our internal circadian clocks with each other, and our internal clocks with the outside world, will surge.”

Mickey Beyer-Clausen’s keynote at the Global Wellness Summit (GWS), on how timing light exposure can eliminate jet lag, inspired this wider trend.


Key facts

The circadian clock in sophisticated life forms (such as mammals) is one extraordinary system. The body’s master clock-controller lives in nerve cells in the brain’s hypothalamus called the suprachiasmatic nucleus, and it’s tuned to the day-night signal by light coming through the eyes and optic nerve. This timekeeping overlord in the brain then orchestrates a network of peripheral clocks that exist in nearly every organ throughout the body (yes, your liver and ovaries have their own clocks), turning on and off a host of clock genes and a wave of timekeeping proteins that rise and fall in a curve in nearly every cell in your body every 24 hours—just like the sun. It’s a magnificent, light-timed cellular choreography that runs on a tight daily cycle and controls almost every body function.

In 2017, a group of researchers won the Nobel Prize in Medicine[6] for discovering how clock genes control our daily rhythms. One of the many circadian genes is the period gene that makes a protein called PER that, in concert with other proteins, builds up at night and degrades during the day in a continuous feedback loop. This controls not just when we sleep but also our heart rate and blood pressure, the immune system, metabolism, body temperature, hormones and even mood. This breakthrough research showed how fundamental the circadian system is in synchronizing our daily biorhythms with the 24-hour rotation of the planet—and how we’re ruled by an inner clock that adapts our body processes to different times of the day with exquisite precision. These clocks are in our DNA.

Disruptions to our circadian rhythms, from those ever-increasing mismatches between our internal clock and lifestyle, when we override our natural cycles, have significant health consequences, including a higher risk of obesity, diabetes, some cancers, heart disease, depression, gut disorders, allergies, infections, premature aging—and early death. There have been more than 650 studies connecting light to health.

Research also increasingly shows[7] how people are chronobiologically hardwired with genes that make us night owls or early birds—called our chronotype. Early risers’ daily peak performance occurs early during the day, while natural night owls’ occurs later. Researchers estimate about 40 percent of people are morning or evening types, and 60 percent are in-between. Our chronotype impacts circadian cycles: Early birds have a faster internal clock, for example, as short as a 23.5-hour cycle, whereas night owls have a slower clock, taking up to 25 hours to complete one cycle. These internal clocks need to be reset, just like a watch, exactly 24 hours each and every day, and the light-dark cycle is the synchronizer.


Dr. Lockley points out some key misconceptions and misusages of the word/ concept “circadian” that can plague sleep and wellness markets—in an era where frustrating “circadian washing” is on the rise.

“Sleep” is not the same as circadian rhythms: Sleep is an output of the circadian clock in combination with another control system, the sleep homeostat, which measures how long we have been awake or asleep. Many other things affect sleep, so measuring sleep is not the same as measuring the clock, and the differences can be enormous. Circadian rhythms are much wider and more complex than sleep, as they impact and orchestrate all of our organs, our brain, and cellular activity.

The circadian clock anticipates environmental time—it does not reflect it or have anything to do with the “social” time of day. The clock anticipates the timed physiology that will happen tomorrow, when we wake/ sleep, eat, etc., to ensure that we do these things at the right time. To be a real circadian rhythm, it must be generated from within.

Just because something is rhythmic, it’s not necessarily circadian: Rhythms that are not generated from within are, by definition, not circadian rhythms. They may have a rhythm peaking in the day (diurnal) or night (nocturnal) but may be generated by an external influence such as physical activity, eating or sleeping. Growth hormone (GH) is a good example. GH is not a circadian rhythm but is a sleep-dependent one: It’s only released during deep sleep, which usually happens at night, and while it, therefore, looks circadian, it isn’t, as the rhythm would go away without sleep occurring and is therefore not internally generated.

As an anticipator, the biological clock thrives on stability: stable, day-in-and-day-out light and dark cues; regular sleep-wake times; regular lifestyles (exercise, eating).

Light governs human circadian biology: Circadian rhythms cannot be meaningfully reset by exercise, stress-reduction, yoga, massage, food, soundbaths, etc.

Forecasting the Future

    • It’s amazing how late we’ve been in understanding—and acting on—how light governs human biology. We need the sun’s bright blue light in the day to be alert/active, and we need dark to kick-start our brain’s sleep mode and recovery. 2020 will be the year more people grasp how to reset their circadian rhythms, the incredible impact they have on their physical and mental health, and how “sleep” and circadian rhythms are not the same things.
    • As Harvard’s Dr. Steven Lockley puts it, “The type and timing of light—will soon become more important than ‘sleep’ in health and wellness. Medical and tech solutions that realign our internal circadian clocks with each other, and our internal clocks with the natural outside world, will surge.”
    • Highest-tech circadian solutions are ahead, but the future is also about changing basic human behavior and human-clock-destroying social institutions. We need to rethink time, light and human life in deep ways—from stopping lighting up our nights with screens to getting out in the natural sunlight to adapting work and school schedules to solar time to addressing our 24/7 culture (from restaurant to gyms) to shielding people from the light pollution exploding in our increasingly urban world to relighting our homes.

This is an excerpt from the “Focus Shifts from Sleep to True Circadian Health” trend in the 2020 Global Wellness Trends Report.

This is an excerpt from the TRENDIUM, a bi-weekly communication exploring the wellness trends identified in the Global Wellness Trends Reports.

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