Circadian refers to any biological process that occur every 24-hours. Our circadian rhythm is like a clock in our system that comes in to play for our sleep process. It determines when we fall asleep and when we wake up. When the sun goes down and it gets dark, more melatonin is produced. Conversely, with the presence of the sun, the production decreases. Exposure to a lot of light in the evenings or not enough light during the day can upset this natural cycle of melatonin production. Some examples that can cause this kind of disruption are:
- Jet lag – This usually results from flying from one timezone to another and is most severe when traveling across many time zones.
- Shift work – People who work at night and must sleep during the day are very likely to have their circadian rhythm disrupted.
- Poor vision – Certain vision problems can upset the melatonin cycle.
- Aging – It is believed by some that aging can affect melatonin levels. That is why many older adults have difficulty sleeping.
Melatonin Supplements and Their Uses
Non-prescription melatonin supplements have been on the market for years and are used to treat numerous different medical conditions. Most are related to sleep problems but there is some scientific evidence to support that they work for some non-sleep related issues as well.
Jet lag and sleep-related uses for melatonin
Clinical trials have shown that melatonin supplements can significantly reduce jet lag. The melatonin should be taken on the first day of travel at approximately the bedtime of the destination and then every night for the next several days. This can decrease the days needed to get into a normal sleep routine, cut down on the time it takes to get to sleep (known as sleep latency), and decrease fatigue during the day.
Delayed Sleep Phase Syndrome (DSPS) – This refers to the difficulty getting to sleep at night even when the natural sleep process has not been disrupted by things like jet lag or too much light in the evenings.
Insomnia in the elderly – Melatonin taken at the same time every evening, approximately 30 to 60 minutes before bedtime, can cut down on the amount of time to get to sleep that often plagues elderly people.
Enhancement of sleep for healthy people – Melatonin taken regularly can even help healthy people who occasionally have sleep issues.
Other uses for Melatonin Supplements
There are conditions for which melatonin may be used that have been studied in trials where the results, while appearing to be positive, are not completely conclusive as to their effectiveness. In many of these cases further studies are planned or are currently on-going.
- Macular degeneration – Melatonin does have some antioxidants which are thought to possibly have some positive affects on the eyes by protecting the retina and delaying the onset of macular degeneration.
- Anti-inflammatory – There is some indication that melatonin acts as an anti-inflammatory agent.
- Anxiety – There have been some positive results when melatonin supplements are used as anti-anxiety medication prior to surgery.
- Cancer – There have been some clinical trials on patients with early stage cancer of different types to discern its usefulness in reducing chemotherapy side effects or in fighting the cancer itself. Results are still inconclusive but more studies are under way.
- Glaucoma – There are theories that melatonin taken in high doses may possibly increase the risk of glaucoma and other age-related eye problems. But these theories are being discounted because of some evidence that melatonin in fact may be useful as a treatment for glaucoma. Until this is more conclusively proven, people with glaucoma should check with their doctor before taking melatonin.
Other studies are trying to prove the usefulness of melatonin for treating headaches, high blood pressure, high cholesterol, irritable bowel syndrome, and numerous other health issues.
Side Effects and Warnings
Studies have shown that melatonin is considered to be safe as long as the recommended dosage is taken, which is 5 milligrams a day for no more than two years. There are some rare case reports where blood clotting, risk of seizure, and disorientation have occurred when overdoses are taken.
Some common minor side effects that have been reported include:
Dizziness, Fatigue (this may happen more if taking melatonin in the mornings or in doses that are too high), Headaches, Sleepiness.
Some people have reported sleepwalking, disorientation, unusually vivid dreams, and nightmares while taking melatonin.