One of the biggest obstacles people face when trying to achieve optimal health is the ability to get not just the right amount of sleep but also the right quality of sleep. In today’s world of late-night TV and artificial lights it’s easy to forget that for thousands of years we lived in sync with the light and dark cycles of day and night.
Our physiology is still the same as our ancient ancestors. Despite the availability of artificial, 24 hour, 365 days a year light, our bodies are still tuned to the natural rhythm of daily and seasonal light/dark cycles.
Our Natural Sleep/Wake Cycles
The cycles of light and dark that result from the movements of the sun affect nearly all living creatures. Whenever light stimulates your skin or eyes, regardless of the source, your brain and hormonal system thinks it’s daytime. In response to light, your hormonal system naturally releases cortisol.
Cortisol is an activating hormone that is released in response to stress, which light is being a form of electromagnetic stress. This activates the body and prepares it for movement, work and other physical tasks. As the sun rises, our cortisol levels also rise and peak between 6am and 9am. They then drop a little but remain high through the middle of the day. In the afternoon and early evening cortisol levels begin dropping as the sun goes down.
Decreasing cortisol levels allow the release of melatonin and increase the levels of growth and repair hormones. If we follow our natural sleep/wake cycles, we start winding down as the sun sets and should fall asleep about 10pm. Physical repair mostly take place when the body is asleep between 10pm and 2am. After 2am the immune and repair energies are more focused on mental repair, which lasts until we awaken.
Disrupted Sleep/Wake Cycles
The continual release of stress hormones like cortisol may be a great idea for someone who is facing a life or death situation, but you don’t want this response to be an everyday occurrence.
A brightly lit house, late night TV and working late into the evening will keep stress hormones high past sundown. Fluorescent lights, TV and computer screens flicker on and off between 60-120 cycles per second, which your brain can interprets as sunlight.
Since cortisol can take hours to clear from your blood stream, this will also prevent the normal release of melatonin, growth hormones and important immune factors, cutting into your immune system’s valuable repair time.
If you go to sleep after midnight you’ve already missed over two hours of your physical repair cycle, which should start around 10pm. People who constantly stay awake after midnight commonly have a list of nagging musculoskeletal injuries, an increased incidence of headaches, and even neurological disorders.
Factors That Can Disrupt Your Sleep/Wake Cycles
1. Stimulants
What do most people do for a pick-me-up when they are tired? Most people reach for something to eat or drink that is sweet or even smoke. Caffeine, sugar and tobacco are all stimulants, which excite your sympathetic nervous system (SNS). This triggers the release of cortisol (stress hormone). Cortisol tells your brain that it’s the start of the day and it’s time to get active.
The most popular form of caffeine is coffee. An eight-ounce cup of coffee contains 300mg of caffeine. Caffeine has a half-life of about six hours. So, if you have a coffee around 3pm, you will still have 150mg of caffeine in your blood at 9pm. Six hours after that, well into the time your immune system is trying to repair you physically and mentally (through the release of growth hormones), you will still have at least 75mg of caffeine stimulating your adrenal glands to produce cortisol levels.
One teaspoon of sugar has been shown to suppress your immune system for as long as four hours. When you consider that the average can of soda contains ten teaspoons of sugar, or that the average breakfast cereal is comprised of between 45% and 55% sugar, you can see how easily sugar finds it way into your diet.
A diet that doesn’t match your metabolic type typically results in large fluctuations of blood sugar levels. Blood sugar levels elevate after eating, triggering the release of insulin to break down and store the blood sugar. To much blood sugar results in an overcompensation response, this in turn leads to a blood sugar low.
Unfortunately, your brain considers low blood sugar to be a dire emergency, a major stressor. Stress hormones are released to counterbalance the condition by triggering the liver to release stored glycogen, which elevates blood sugar. Meanwhile, most people respond to the effects of low blood sugar by consuming something high in sugar or caffeine before the liver can do its job.
This cycle keeps cortisol levels high, preventing the body from winding down so it can release growth hormones. Maintaining a steady blood sugar level throughout your day will help maintain the right levels of stress and growth hormones, allowing you to sleep better.
2. Electromagnetic Pollution
Unless you regularly sleep in a cave miles away from human civilization, you will probably be exposed to low frequency electromagnetic energies. Power lines, electrical circuits in your walls, ceilings and floors and electrical appliances such as electric blankets, TVs all emit such energies. This electromagnetic pollution can disrupt natural sleep/wake cycles.
3. Entrainment
Physiologists and medical doctors have found that you can be entrained, or synchronized to a dysfunctional schedule in as little as 7-21 days. This means that if you stay up until midnight for one to three weeks in a row, your internal body clock will become trained to wait until midnight to start reducing cortisol output and increasing melatonin production.
Just because you didn’t start the physical repair on time doesn’t mean its going to get jammed in. your natural rhythms will automatically begin the psychogenic repair around 2am, thus robbing your body of two good hours of physical repair.
If your body gets used to going to bed late and you then decide to get to bed earlier one night, you will probably, find out you have a hard time falling asleep at 10.30pm. Now you are faced with the task of entraining your system to release your sleep time chemicals early enough so that you can get to sleep on time for a full cycle of physical repair.
Chris, myHealthCoach