I went through this in a previous post about an article I pulled from Eric Schmitt’s personal instagram: observing what people you admire or respect are reading can help you know what you should read. I got Circadian Code from a podcast that Robert Jacobs did which was listed on his Instagram page. He was talking about different light therapies and how they influence metabolism. He only quickly mentioned the author Satchin Panda, but it influenced me to conjure up a lot of thoughts on managing your eating and lifestyle around when we receive the most light.
Really user friendly book, first and foremost. There are a lot of very deep cellular physiology books that one could go into by Gerald Pollack or Gilbert Ling or into light spectrums and their impact on cellular function by Roeland van Wijk. I honestly get so lost reading these books because they are so into the research. It is literally like reading a transcribed sequence of how this research came to conclusions that profoundly shaped modern biology. It becomes increasingly harder to have someone pull you out of these depths and come up with something practical.
At a certain point, there needs to be something more tangible. It’s comforting to know that I could eventually explain what I’m reading to someone. The central theme really of the book is that every function in the body is Circadian, or runs from an innate clock. How our digestive system operates, how our immune system operates, how our nervous system operates, how our detoxification system operates, and how our endocrine system operates are running off a clock. This clock is based on when light is and is not present.
The retina, the light sensitive tissue lining of the back of our eye, contains several million rod and cone light sensors. Light rays are focussed onto the retina through our cornea, pupil, and lens. The retina converts the light rays into impulses that travel through the optic nerve to our brain, where they are interpreted as images we see.
Panda
There is a special light sensing protein outside the rod and cone that senses light which is called melanopsin. Melanopsin encodes information into the brain when it is dark and light. This in turn creates an order of systems that will take precedence of one system over another based on the amount of light received. For instance, during light periods, the Sympathetic nervous system takes precedence over the Parasympathetic nervous system. This reverses when it is dark. What eventually happens is that certain systems work in the place where light is present for highest optimal function like procuring food or fulfilling physical tasks. When light is not present systems that allow for restoration and recovery take over.
Where this concept really gets interesting is the timing of food around this circadian clock. The central theme is built around Time Restricted Eating (TRE). TRE is the timing of food within a window around your sleep-wake cycles. This is established to develop a synchronicity with when we eat and when we are awake. Eating food will have a direct impact on our gastrointestinal system and our endocrine system. In large, this will have a direct effect on our ability to sleep restfully. This is a nutrient timing, or energy timing, strategy that ties into a larger framework of when we sleep based on light.
This becomes really layered as we add in modern elements such as blue light from screens. Complications arise when we add in modern stressors such as variable work schedules. A huge component around Circadian function was based on just how poor immune and cognitive function shift workers display. This was in turn used as the hypothesis of looking at how light and darkness affect biological processes. To test these hypotheses, a ton of laboratory experiments were conducted utilizing mice and various other species that work around their natural circadian clock.
Looking at shift workers is not a far reach from most of the people we talk to on a daily basis in our everyday practice. How many athletes stay up way past the sun going down and rely on screens and LED lighting? The light we are constantly exposing ourselves to is altering the natural rhythms of our systems. If the body perceives it to be light, and it is well past the time our cells are expecting to reset or relax, we will struggle to function.
We are going to have to find strategies to help people go to bed earlier. We are also going to have to find strategies to get people to sleep consistently. If it’s a Time Restricted Eating approach or a Light Management Approach, this book can be really helpful. Good read, very practical, definitely got me thinking about what in my everyday life I should be more conscious of.