Sleep & Circadian Rhythms

November 04, 2013


By Dr. Marc Bubbs ND
In the Paleolithic or ‘hunter-gatherer’ era more than 10,000 years ago, our ancient ancestors woke up with the rising sun in the morning and rested for a good nights sleep not long after sundown.  Scientists believe that our hunter-gatherer ancestors averaged about 10 hours of sleep per night.  Of course the absence of an external light source, television sets, and laptops made it a little easier to get to bed so early, but the benefits are deeply engrained in our DNA.   Your circadian rhythms are based on the light and dark cycles of the day and have a profound effect on your bodyweight, cardiovascular health, fertility, and well being.

Melatonin is your body’s sleep hormone and is secreted in the evening about 3 hours after your last meal.  It naturally winds you down and prepares you for deep nights sleep.  The melatonin hormone initiates a cascade of reactions that results in the production of growth hormone (GH) during deep sleep, allowing you to repair and rejuvenate overnight. Growth hormone is essential for recharging your body while you sleep, building lean muscle, burning body-fat and keep, and boosting immunity.  It is often referred to as the ‘fountain of youth’ hormone for its abilities to repair and recharge the body.  Your immune and hormonal systems are intricately linked to these evolutionary circadian rhythms of light and dark, and understanding how they work will help you build muscle, burn fat, and feel healthier than ever.

Cortisol is your body’s stress hormone and it works in concert with melatonin to establish your daily circadian rhythms. Cortisol is the yinto melatonin’s yang. For example, morning daylight increases your cortisol production naturally to help get you up out of bed, alert, and ready for a busy day.  Cortisol should naturally be high at the start of the day. If not, you may need to hit snooze several times before getting out of bed or require a caffeine boost to get yourself going in the morning.

Your natural cortisol/melatonin circadian rhythm shifts throughout the day and by nightfall your cortisol levels should be decreasing to their lowest levels. If you struggle to fall asleep or wake up frequently during the night, your evening cortisol levels may be out of balance.

So how does this rhythm lose its natural balance? Multiple factors can lead to circadian rhythm dysfunction, including; lack of sleep, stress, long busy workdays, too much TV or WIFI stimulation, excessive use of stimulants like coffee and sugar. Two generations ago, our grandparents average about 9-10 hours sleep per night, not very far off our Paleolithic ancestors.  Today, the average North American gets between 6-7.5 hours of sleep, about an hour or two less than the recommended 7.5 to 8.5 hours sleep per night.  Over the course of a year, this would amount to approximately a 500-hour ‘sleep debt’ that needs to be made up.  When your total sleep time drops too low, your cortisol stress hormone will rise along with the hormone ghrelin, which is responsible for triggering hunger. The fewer hours you sleep, the greater your hunger cravings! Studies show that those people sleeping less than 7 hours per night gain more weight than those getting adequate sleep (greater than 7 hours).

Another potential factor contributing to circadian rhythm dysfunction and poor sleep is the overuse of stimulants like caffeine to provide an artificial boost to your morning.  Coffee triggers the production of adrenaline and cortisol from the adrenal glands and stimulates your sympathetic – ‘fight or flight’ – nervous system.  It is the number one stimulant of choice and chronically high coffee intake raises cortisol levels, which can deplete your adrenal glands and leave you feeling even more fatigued in the long run. While coffee can be a very healthy beverage packed with antioxidants, the old adage is still true…’you can get too much of a good thing!’ If your intake has been the same for several months (or years for some) then it’s time to give your body a break. Also, if you don’t feel any extra boost after your morning coffee, or if you get headaches when going without, then your body has definitely become dull to the stimulus and your cortisol levels will be low.

So what can you do to get your circadian rhythm back in balance? First off, it’s important to get tested to determine your actual circadian cortisol rhythm. This will provide a baseline level from which to evaluate your progress going forward. The test is called a ‘Four Point Cortisol Test’ and measures your cortisol upon rising, midday, afternoon, and bedtime to determine your levels throughout the day.  This provides powerful data to determine the underlying cause of your circadian dysfunction. The results of this test will guide the nutritional and supplemental interventions that are best suited for you. Next, eliminating all stimulants (i.e. coffee) for two weeks is critical to reduce the burden and demand on your adrenal glands. Lastly, try to eliminate any added nervous system stimulants before bed. This means turning off the television or shutting off your laptop at least an hour before bed to allow your body to unwind.  All of these stimulants activate the nervous system and prevent deep sleep.

Hopefully, these simple tips can help you maintain your health and performance as you move into the fall and winter seasons. Enjoy!

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image via Viktor Hertz via Compfight

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