The Circadian Rhythm and Sleep
When you feel the effects of jet lag or when you feel tired after working a rotating shift during the week what is actually is happening is that your body’s circadian rhythm is out of sync with your activities.
The word circadian is derived from the Latin words “circa diem” which translated into English, means about a day. As far as the human body is concerned, one day refers to a 24-hour period.
Although most commonly associated sleep patterns the circadian rhythm also has a direct influence on our blood pressure, our body temperature and our body’s production of hormones. Together these internal changes tell the body when it is time to sleep and to wake. When we mess with our circadian rhythm we feel drowsy and generally unwell. When we go to bed we may find it hard to sleep and if sleep comes we will find ourselves needing to get p and go to the bathroom more often than usual. In other words you are trying to create night ot of day and it takes time for your circadian rhythm to get back in sync.
Rhythm is a very big part of nature. For example, we know that the Earth completes a rotation every 24-hours and that year after year, the seasons change from winter to spring to summer to autumn and then back again to winter. Therefore, circadian rhythm plays a significant role in animals’ lives as well. The most notable example of an annual natural rhythm is the migration of countless species of birds every year.
When it comes to the sleep-wake cycle, there are two primary environmental forces at work: light and temperature. Circadian rhythm can also be affected by other stimuli such as the sound of your alarm clock and what and when you have eaten, and in women, their menstrual cycles.
Internally, the circadian rhythm is influenced by an ‘internal body clock’ located in the part of brain called the hypothalamus. Specifically, two large clusters of neurons situated on either side of the brain called the suprachiasmatic nuclei or SCN is considered the body’s master clock. The SCN work with other genes to help the body keep track of time. The stimulation and/or release of different chemicals, hormones and neurotransmitters is how the body knows when it is time to fall asleep and to wake up, when it’s time to eat and when it’s time to have intercourse and more.
When it comes to sleep, the following is a simplistic overview of how the circadian rhythm works. At the first sign of daylight, the body begins to produce hormones and neurotransmitters including serotonin and cortisol. These help the body transition into an awakened mode by increasing body temperature and blood pressure. Likewise, as daylight fades, the body begins to release melatonin, the main signal that tells the body to begin lowering blood pressure and to prepare itself for sleep.
When the body’s circadian rhythm is in balance, it dictates the proper timing and release of these important chemicals, hormones and neurotransmitters. However, when the body’s circadian rhythm is ‘off’ this timing and release is knocked out of balance. A prolonged imbalance can and often does lead to the development of a number of sleep disorders and emotional disturbances. It would seem then that being healthy and happy is all about keeping your circadian rhythm in check.
Sleep though natural and essential is often an elusive condition. If you have insomnia it could be that you are not secreting enough melatonin in the late evening.
Melatonin is a hormone that is secreted by the pineal gland located at the base of the brain. It is secreted at varying levels throughout the day and its release helps to regulate the body’s sleep-wake cycle. The onset of darkness stimulates the pineal gland to release melatonin.
During the day, the melatonin levels are barely traceable. As darkness arrives, the pineal gland starts releasing more melatonin into the bloodstream. As more melatonin travels throughout the blood, you become sleepy and ready to go to sleep. Your melatonin level continues to increase until it peaks at around 3 or 4 a.m. After that melatonin levels slowly begin to fall and you will wake up a few hours later.
Anything that disrupts the normal release of melatonin can also disrupt sleep patterns. Your body knows that when melatonin is low that means that it should be alert and awake and ready for the day. Increased melatonin production signals that it is time to go back to sleep. Darkness at any time of day can trigger the release of melatonin and the changes that naturally take place with its release. The weather can have a direct effect on the production of melatonin, especially on overcast days or during the winter months with fewer hours of sunlight.
Working inside a windowless office that lacks suitable artificial lighting can also cause problems for melatonin production. Such conditions can cause melatonin levels to remain higher than normal during daytime, and may cause a person to feel less energetic and drowsy during the day. When more melatonin is released throughout the day, less will be released during the night, and this imbalance can cause insomnia and other sleeping disorders.
Light therapy can help when natural sunlight isn’t available. However the best way to keep melatonin levels balanced is by allowing natural sunlight to reach your skin. Go for a walk in your lunch break and any other time you are able to. If you work in a cubicle maybe you could wangle a move to a window seat. Whatever you do try to get enough light during the day.
Conversly when evening comes its time to reduce the light you are exposed to. Don’t sit in front of a computer screen. Try to reduce electric light as bedtime draws nearer. Remember until Alexander Graham Bell invented the light bulb we all had low light or no light after dark. That is the way our bodies developed over the millenia, and they haven’t changed.
If you are still having problems sleeping after trying all the other remedies you might be helped by melatonin capsules taken at night. These don’t help everyone but some people have been greatly helped by them. Remember they are a hormone so don’t eat them indiscriminately and never give them to growing children.
Using a sleep mp3 audio can also help you to sleep at night.