How Does Light Affect The Wake-Up Patterns After Sleep?
Sleep is the natural and periodic state of rest that all the animals go through. Sleeping habits are different in different parts of the world. These differences are visible between the cultures where artificial light is used and the ones where it is not common.
Research indicates that cultures with less artificial light (mostly in the old days) have broken-up sleep patterns. Thus, people tend to sleep in periods, waking up after every few hours depending on various things. However, it has been proven that light plays a crucial role in the way people wake up after sleeping. Apparently, sleep patterns have changed after the inception of the artificial light, with people generally sleeping for solid hours and waking up after a constant amount of sleep, as opposed to waking up after short spans of time.
Researchers are still trying to figure out as to how bright lights can help a person change his sleeping patterns, or overcome depression. One theory that scientists have adopted is that when light enters the visual pathways, it triggers an area near the eye, which is responsible for signalling the suppression of melatonin, a hormone which helps regulate our sleep and wakefulness. Melatonin is capable of regulating our sleep-wake schedule and inducing sleep when body is not tired.
Initial theories suggested a pathway from the retina to this specific area of the brain. On the other hand, some latest research indicated that bright light applied to the back of the knee of an individual could shift human circadian rhythms (Daily sleep-wake cycle). This suggests that the bloodstream, in addition to the neurons of the visual pathways, might affect the biological clock.
Regulation of light may also help how people wake up, which may particularly be important for individuals suffering from certain disorders. For example, winter depression or the cold blues, more commonly known as Seasonal Affective Disorder, (SAD) is when people with relatively normal mental health and disposition, seen as mentally and emotionally healthy individuals for most of the year, experience symptoms of depression most commonly in the winter, and sometimes at the change of other seasons, such as summer, spring or fall. Normally, this is a reoccurring phenomenon, and can be observed over time and also on an annual basis, in that particular season.
One of the side effects of this disorder is abnormal sleep patterns, and one of the effective methods of treating it has been light therapy. This involves very bright light bulbs being used to illuminate an area where the subject is asked to sit.
As everyone may have observed at some point, when somebody is woken up by drawing the curtains to allow sunlight into a room, he/she normally wakes up immediately; manifesting the effect light has on the sleep of a person. However, a person woken in this manner is more likely to be irritable.
Recently, many more products have been commenced in the market that introduce light to the room gradually rather than throwing immediate harsh lighting. This helps a person wake up slowly; as compared to the shock one receives due to sudden exposure to bright lights. Most people find this new option a friendlier choice. Therefore, we can conclude that light does play an important role in our lives and in out sleep-wake patterns.