Wednesday, January 2, 2019

humanOS Year in Review (Part 3 of 3): Circadian Rhythms, Sleep, and the Brain

In the third and final instalment of this series, we’ll look back on what we learned about circadian rhythms, light exposure, sleep, and the brain in the last 12 months. If you missed the first two blogs in the series, here’s the first and here’s the second. To end, we’ll look to 2019 as we peer into the pipeline of humanOS.


Circadian rhythms shape all aspects of our biology and behavior

The last blog ended on the subject of fasting. This segues seamlessly into that of chrononutrition. People contributing to a particular research topic often use the start of the names of their field of study as a prefix for other words. So, neurobiologists speak of “neuroinflammation”. And chronobiologists prattle about “chrononutrition”. As I detailed in this talk, the premises behind chrononutrition are that 1) the times of your body’s clocks influence what your body does with the foods and drinks you consume, and 2) the foods and drinks you consume influence the times of your body’s clocks. So, it’s not only what you eat that matters, when you eat is critical too. Dan and I created a guide that summarizes key chrononutrition principles that you can apply to your own diet.

Now while diet influences the function of your body’s clocks, it’s not the only influence, as I detailed in four courses earlier this year. The first of these introduces why our bodies evolved to have clocks (to anticipate and adapt to predictable environmental changes), the second explains how our clocks work (a network of clocks that needs resetting daily), the third details the pre-eminence of our clocks in metabolism (our clocks separate the timing of incompatible metabolic processes), and the fourth shows you what you can do to keep your clocks on time (get outside, be physically active, and eat during the day. Then rest and fast in darkness at night). My guess is that if you are in the Northern Hemisphere then some of you are all too familiar with how debilitating circadian system disruption can be at this time of year. I gave some reasons as to why this may be the case in this blog on circadian system disruption and mood disorders.


Light exposure is pivotal to good health

Whereas diet is an important determinant of the timing of many of your body’s clocks, your patterns of exposure to light are most important to setting the time of the master clock in your brain. This clock strongly influences when you sleep. But some captivating research from the last few years has shed light (ahem) on why these exposures are about so much more than sleep, as Dan brilliantly elaborated in his TEDx talk. This same link includes Ginny’s review of a study showing that light exposure can substantially affect blood pressure too.

In his presentation, Dan discussed preliminary evidence showing that exposure to blue light may influence how much fat we burn, and he discussed this research with Peter Light, senior author on the paper. Dan also mentioned work on how insufficient light exposure detrimentally affects the brains of rats, which he discussed with Antonio Nunez.


As our understanding of sleep improves, so do our strategies to improve it

Too much exposure to certain types of light late in your biological day can wreak havoc on your sleep. As the study on creatine and sleep that I mentioned in the last blog shows, however, an array of factors affects sleep. One way by which creatine supplementation reduces the pressure to sleep is by changing levels of inflammatory chemicals in the brain. Dan explored this topic more when he interviewed Mimi Shirasu-Hiza about her research on the bidirectional relationship between sleep and oxidative stress in fruit flies. Those of you interested in the biology of sleep may also enjoy Dan’s interview with John Peever. They discussed rapid eye movement sleep, the bizarre stage in which although most muscles are paralyzed, heart rate fluctuates dramatically, and parts of the brain are even more metabolically active than they are during wakefulness!

While it’s fun to study what goes on in our bodies during sleep, research on large groups of people is needed to understand how sleep relates to risk of disease in humans. Kristen Knutson has done many large-scale studies in recent years, and in this podcast she explained the importance of the circadian system and sleep in cardiovascular health. Kristen’s work points to the therapeutic potential of interventions to improve sleep, and Kristine Wilckens discussed ways of enhancing deep sleep in this episode of humanOS Radio. I spoke a little about this subject in a talk I gave earlier in the year too.

While some novel ways of improving sleep may involve strange devices, there are simple, practical, and proven strategies that most of us can benefit from. I wrote about several of these on the blog this year. After first discussing some of the numerous positive effects that getting more sleep has on people who habitually restrict their sleep in this blog, I shared several ways that most of us can get more restorative slumber here. Many of us have experienced record highs in temperature this year, during which you may have noticed how temperature affects sleep. Most recently, we explored why making a to-do list at bedtime may help you fall asleep faster. And if you manage to nod off but then struggle to stay asleep, you might find that meditation helps quiet your mind and get back to sleep.

Here's some of what we learned about circadian rhythms, sleep, and the brain in 2018
Click To Tweet


Brain function strongly shapes your experience of the world. So, how can you support your brain health?

Few things influence brain function as much as sleep does, and focusing on optimizing your sleep routine is a logical starting point if you want a better brain. But as we’ve highlighted on humanOS this year, many other factors can sharpen or blunt your mind. Unsurprisingly, one of these is physical activity or, more precisely, inactivity. Ginny discussed this topic in a blog reviewing a study of the adverse effects of hindlimb unloading on the brains of mice.

If ketosis has been the darling of the dietary world this year, psychedelics may well have been their equivalent in the world of mental health. I find this very encouraging, for the little science that has been done on these drugs to date is both promising and captivating. Ginny wrote about some of Robin Carhart-Harris’s terrific work in this post on the remarkable efficacy of psilocybin in the treatment of patients who had treatment-resistant depression. Psychedelics seem to be perhaps unprecedented in their ability to temporarily disrupt deeply entrenched patterns of brain activity. But in addition to psychedelics, there are less forceful tools that still have pronounced effects on the wiring of our brains. Neurofeedback may be one of these, as Andrew Hill explained in this podcast.


Peering into 2019

The dawn of a new year is often a period of reflection. You might think that it’s not the “right” time to try to make changes in your life. Nobody sticks to New Year’s resolutions anyway, right?

But perhaps now actually is the best time to replace unwanted habits with desirable ones. Sure, this switch isn’t always straightforward. But there are things you can try to make it easier, as James Clear clarified (sorry) in this excellent podcastAs you listen, you may want to reflect on the questions Dan asked in the first post of this series:

  1. How do I make today a healthy one?
  2. How will I be better at serving my health one year from now?
  3. What do I want to learn well?
  4. What do I want to try?
  5. What do I want to maintain?
  6. What do I want to change?
  7. What will I spend this year getting better at?


humanOS in 2019

Next year you can expect us to implement various upgrades to our offerings here at humanOS. What are just a few of the developments we have in store for you?

First, you can expect various improvements to your user experience of humanOS. There’ll be new tools that you can add to your dashboard to help you better navigate your day. And for our group offering, you’ll soon be able to compete with your co-workers over a range of different metrics, like average daily steps or course lessons watched in a month. Get in touch with us at if you’re interested to have help your company’s health performance in 2019. 

Speaking of which, we have some great content that is nearly ready to publish too. This includes courses on physical activity and the paleo diet, and we’ll be sharing our sleep program with you next year too. I’m particularly excited about this one… let’s just say there’s nothing quite like it!

We may also have some especially exciting news for you next year, but we don’t want to jump the gun on this one. You’ll definitely want to stay tuned for it though!


Be well!

Happy holidays from the team here at humanOS. We wish you well and hope you’ve had a terrific break with your loved ones. We’re thrilled to continue to do our best to serve you in 2019!



Make 2019 your best year yet in your pursuit to master your health. Pro membership of costs just $9.99 per month, and Pro membership gives you access to all our courses, how-to guides, tools, recipes, and workouts. Pro members also support our work on blogs and podcasts.

The post humanOS Year in Review (Part 3 of 3): Circadian Rhythms, Sleep, and the Brain appeared first on

No comments:

Post a Comment