Your SCN is your very best friend

Sometimes in life, we find out a piece of information that makes us feel like we have fallen out of the matrix for a moment. We ask ourselves, 'How did I not know this?'

Learning about the SCN might just be one of those times.

The big sciencey word that the three letters represent is Suprachiasmatic Nucleus. Supra-chias-matic nucleus.

What does it do? Well, think of it as an orchestra conductor and timepiece for your entire body.

The SCN sends messages to the body clocks within your organs, and tells them when to start and stop the release all of the various, perfectly timed chemicals and processes which create a healthy you throughout the day. Think melatonin release, cortisol rhythm, body temperature rhythm, sleep timing, feeding and metabolism and mood regulation.

You've probably heard of your 'circadian rhythm'. This is the downstream cascade of physiological processes that follow the timing signal of the SCN, i.e. it is the orchestra conductor telling all the organs when to start and stop their processes.

So, in a nutshell, here is what happens:

One wakes up and gets early morning photons directly into the back of their eyeballs (this is how the SCN wakes up). This occurs when someone gets at least ten minutes of sunlight without sunglasses on in the morning light, just after sunrise. This signals the SCN to start the orchestra. Throughout the day, the body's rhythm of chemical release and processes flows smoothly. By the end of the day (12 to 14 hours after the initial sunlight exposure) the body automatically starts pumping melatonin for a high-melatonin sleep, which activates the glymphatic system (like a dishwasher) which cleans neurotoxic waste from the brain. But what happens when the SCN is confused? So what if, for example, from the age that we were old enough to go to bed when we wanted (say early teens) we stayed up late? What if we started watching scary movies or serial killer documentaries, pumping the fear signals and filling our brains with blue lights late into the night? What if we then slept in and didn't get up and get those photons directly into the back of our eyeballs?

A confused SCN leads to confused body clocks in every major system in our bodies. Chronic circadian misalignment essentially means a confused SCN. Some of the long-term effects can be:

• Hormonal and cortisol dysfunction: suppressed melatonin production, sleep issues, less effective glymphatic system (toxin filtering in the brain and spine).

• Mood disorders and mental health problems: chronic circadian misalignment strongly correlates with higher rates of major depressive disorder, anxiety and seasonal effective changes.

• Metabolic desynchronisation: liver, pancreas and gut problems.

• Cardiovascular and immune strain: blood pressure problems and inflammation.

• Social jetlag and sleep debt: leading to chronic sleep deprivation.

However, the good news is, the SCN is remarkably resilient. Why? Because it is controlled by neural pathways, and thank goodness for neural plasticity!

So, even decades of late-night habits can be shifted back into alignment using targeted morning sunlight exposure (10 minutes, no sunglasses), consistent sleep times and limiting blue-light exposure. In this way, our SCN can become our best friend!