This article is an ode to one of my favorite researchers, Dr. Satchin Panda. He runs a circadian biology lab at the renowned Salk Institute. As a nature-obsessed health coach, I love that Panda’s research illustrates the biological mechanism for my suspicion that nature is the ultimate health resource. He studies our circadian rhythm - how the timing of environmental inputs impacts our physiology.
Naturally, I was thrilled when he came out with his book, The Circadian Code. Most of the information in this post comes directly from the research cited in his book. Check out the whole book for a fantastic primer on optimizing your circadian biology for health.
Circadian biology illustrates how interconnected our physiology is with the natural world. Our brains and clock genes sense cues from the environment and respond with hormonal outputs. Circadian disruption occurs when our internal clocks are confused by conflicting external cues. Circadian disruption is related to over 100 different illnesses. When the timing is inconsistent or inputs out of sync with each other, human health can suffer. As such, time is an underrated health resource that can be leveraged in potent ways.
Due to the circadian impacts, camping is a health elixir. I don’t know about you but I never feel better than on a backpacking trip. One explanation for the vitality you may feel is that camping creates circadian alignment by ensuring that you are eating, moving, and getting natural light during the day and sleeping, fasting, and in a dark environment at night.
Couple this with all-day movement and fresh air and its easy to see why camping is a powerful health promoter. Interestingly, camping has been studied as a way to re-align circadian rhythms (more on that here and here). The trick is mimicking these patterns in our day-to-day lives.
We have a master clock in the brain (the suprachiasmatic nucleus) and peripheral clocks (clock genes throughout the body). Ideally, your master clock lines up with the peripheral clocks and both line up with the light-dark cycles in the natural world.
Optimal health occurs when the master and peripheral clock are in sync with each other and both clocks are in sync with natural cycles of light and dark in your environment.
To make this groundbreaking information practical, here are the 4 essential habits to adopt for circadian optimization:
Move in the morning
Keep a consistent sleep schedule - making sure to go to bed before 11 pm.
Eat all your food in a 12-hour window and stop eating at least 3 hours before bed (8 pm at the latest).
Get as much daylight during the day, as little light as possible at night, and no light during sleep.
Let’s dive a little deeper into each tip.
MOVE IN THE MORNING:
“When we are not eating or sleeping, we’re supposed to be engaged in some form of physical activity” - Satchin Panda
Obviously, moving at any time is better than not moving at all. But, if you are looking to optimize your exercise routine, morning is the ideal time.
You get a 12-hour mood boost from exercise so it’s nice to benefit from this endorphin high during the day.
You get daylight exposure at the right time to entrain your circadian rhythm and sync up your brain clock.
Exercising in a fasted state appears to have some benefits, such as burning more fat and increasing autophagy (clearing out dead or damaged cells). In light of this, exercising before breakfast is a wise choice.
You’ll raise your cortisol curve at the appropriate time, which can lower inflammation and set you up for a healthy circadian rhythm later in the day.
HAVE A REGULAR WAKETIME AND BEDTIME!
When it comes to sleep, regularity is king! This is the #1 sleep tip from sleep guru, Dr.Matthew Walker, and is reiterated by Dr. Satchin Panda. The quality and quantity of your sleep drastically improve when you stick to a routine.
Here’s how to do it.
Establish a regular bedtime and wake time. Stick to this even on weekends.
If you stay up late, try to wake up at the same time the next day. If you sleep in you likely won’t be tired at your usual bedtime and you’ll shift your circadian clock. This leads to a form of “social jetlag” ( where your circadian rhythm shifts due to your social calendar on the weekend vs the weekday). Just get up, deal with the sleepiness, and try to get to bed at your usual bedtime that night.
The best way to actually establish a regular bedtime is to set a solid digital curfew. Set an alarm on your phone for 1 hour before your ideal bedtime. At this time, turn off your phone and devices and start winding down.
EAT YOUR FOOD WITHIN A 12 HOUR WINDOW AND STOP EATING AT LEAST 3 HOURS BEFORE BED (Ideally 8 pm at the latest):
Food is as important as a circadian cue as light. Light sets your master clock and food appears to set all the other clocks in your body (peripheral clocks).
Ideally, your light and food cues are giving your body the same signal. If not, circadian disruption can occur.
So, let’s talk about timing your eating for circadian alignment.
Intermittent fasting is all the rage. While there is some compelling research behind the hype, unfortunately, the data is new and due to its restrictive nature, it can be psychologically triggering for people with a history of any type of disordered eating.
So for now, don’t worry about the extremes, and instead, try a circadian-informed 12-hour eating window.
Here is how to do it: You don’t change the amount or quality of what you are eating but just the time frame. You simply try to eat all your food within the same 12-hour window each day and stop eating at least 3 hours before bed (known as a 12/3 fast). Obviously, this won’t happen every single day but stick to your schedule as often as possible.
One reason is that when you eat right before you go to sleep the digestion process keeps your core body temperature elevated. Since a drop in your core body temperature is one of the signals that initiate sleep, eating too close to bedtime diminishes the amount of deep sleep you can get.
Another reason is that when you are digesting food, you are not in “repair mode.” Your body thinks it is “daytime” and does not initiate the nighttime repair mechanisms that occur when you’re asleep in a fasted state.
For a great deep dive of the research around this eating pattern, check out this ted talk by one of Satchin Panda’s research collaborators, Emily Manoogian.
GET AS MUCH DAYLIGHT DURING THE DAY, AS LITTLE LIGHT AS POSSIBLE AT NIGHT, AND NO LIGHT DURING SLEEP.
The simple rule of thumb is to expose yourself to as much daylight as possible during the day, as little light as possible in the evening, and absolutely no light when you sleep (i.e., sleep in complete darkness). - Satchin Panda
Here’s how to make it happen:
Expose yourself to lots of bright light during the day (without sunglasses on!), which will boost your ability to sleep at night, as well as your mood and alertness during the day. The most powerful light for daytime anchoring is before 8:30 am. Try to get out in the early morning for at least 10-20 minutes. Prioritize a daily morning walk outside to make this a habit.
Avoid looking at bright screens at night. Decide on a screen curfew time (at least one hour before ideal bedtime) and do your best to stick with it. Set a digital sunset alarm on your phone as a reminder.
If you work a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses. I like the Uvex brand, which you can buy on amazon. Download the f.lux program on your computer which blocks blue light as it gets dark: https://justgetflux.com/. Nightshift is the equivalent for iPhone but only available for IOS 9.3 http://www.apple.com/ios/preview/.
Sleep in total darkness -- Take all devices out of the bedroom, use an eye mask, and blackout curtains if necessary.
It’s no small task to live in alignment with the natural world and your circadian system.
To begin, break it down into the essential habits in each area: light, movement, eating, and sleep. Track your progress to see what is going well and what needs a little work. To make this easier, I created a free circadian habit tracker below to get you started.
As always, I’d be thrilled to be your health coach if you need a little extra support.
Circadian Rhythm Alignment Tracker :
(adapted from The Circadian Code by Satchin Panda)
“You can maintain a robust clock and preserve your normal brain function by following four simple habits: sleep, TRE, exercise, and the appropriate exposure to daylight.” - Dr. Satchin Panda
Working on optimizing your circadian rhythms is one of the strongest levers for improving overall health.