Did you know your Sleep has a Circadian Rhythm?
I’ve got rhythm, I’ve got rhythm. Do you remember those lyrics to a song? Well sleep has rhythm too - Circadian Rhythm.
Circadian rhythms are controlled by the body’s biological clock. This clock, called the suprachiasmatic nucleus or SCN, is actually a pair of pinhead-sized brain structures that contain about 20,000 neurons. The SCN is in the part of the brain called the hypothalamus. Light that reaches photoreceptors in the retina (a tissue at the back of the eye) creates signals that travel along the optic nerve to the SCN.
Signals from the SCN travel to several brain areas, including the pineal gland. This gland switches off production of the hormone melatonin when introduced to light. Melatonin increases after darkness so people feel sleepy. The SCN also controls body temperature, hormone secretion, urine production, and changes in blood pressure.
Our biological cycles normally follow the 24-hour cycle of the sun. Our circadian rhythms can be affected by any kind of external stimulus - such as noises and light.
When travelers pass from one time zone to another, they experience jet lag because their circadian rhythm has been disturbed. It usually takes several days for your body’s cycles to adjust to the new time.
To reduce the effects of jet lag, some doctors try to manipulate the biological clock with a technique called light therapy. They expose people to special lights, many times brighter than ordinary household light, for several hours near the time the subjects want to wake up. This helps them reset their biological clocks and adjust to a new time zone.
Jet lag symptoms are common in people who work nights shifts. These people work schedules that are in conflict with normal circadian rhythm cycles. They often are drowsy during work, and may have insomnia when they try to sleep. Shift workers have an increased risk of heart problems, digestive disturbances, and emotional and mental problems, all of which may be related to their sleeping problems. Workplace accidents increase during the night shift due to fatigue. It may be possible to reduce shift-related fatigue by using bright lights in the workplace, minimizing shift changes, and taking scheduled naps.
People with total blindness experience life-long sleeping problems because their retinas are unable to detect light. Daily supplements of melatonin may improve night-time sleep for such patients. However, since the high doses of melatonin found in most supplements can build up in the body, long-term use of this substance may create new problems. The side effects of melatonin supplements are still unknown.
My circadin rhythm is calling me. See you next time.
Good Night to All,
Cheryl