The Circadian Code summary

In addition to sleeping and waking, your circadian clock regulates the timing of thousands of genes, turning them on or off at specific times of day in every cell and tissue. When we disrupt clocks, even genes get out of sync.

For example, genes involved in digestion, metabolism, or cell repair activate on daily cycles. Disrupted clocks lead to these processes happening at the wrong times. Staying up late with light exposure can reset the master body clock in the brain, tricking it into thinking it's daytime. This puts it out of sync with other organ clocks.

There are three core circadian rhythms that are essential for health – and they relate to sleeping, eating, and being active. These rhythms are interconnected, and optimizing them can profoundly affect well-being.

In addition to all the other health benefits we’ve covered, circadian rhythms are also essential for maintaining brain health and preventing neurological diseases. Nearly every part of the brain has an intrinsic circadian clock that regulates its function. Disrupting these clocks contributes to many mental health issues.

Circadian rhythms profoundly influence immune function and cancer susceptibility. Nearly all immune cells and processes follow innate 24-hour cycles for optimal defense. So disrupting clocks leads to an imbalance among immune components, which can cause the systemic inflammation underlying many chronic diseases. This means that things like shift work or pulling an all-nighter elevate infection risk and cancer odds.

The circadian clock controls cellular defense processes like autophagy – the recycling of cellular waste. Autophagy follows a daily rhythm, peaking during overnight fasting. Circadian clocks also regulate the production of antioxidants to neutralize oxidative stress from metabolism. 

Nearly every aspect of eating and digestion follows daily cycles for optimal function, and misaligning these digestive clocks leads to many common GI issues. The production of enzymes, stomach acid, gut motility, nutrient absorption and more are all circadian processes.

In particular, late-night eating is especially disruptive, as it triggers excess stomach acid when repair processes are underway. This can cause acid reflux and create long-term damage.