17 Oct Melatonin – the Dracula of hormones!
Melatonin is a hormone produced by the pineal gland which is located in the centre of your brain. Like the vampire Dracula, the pineal gland is inactive during the day but when the sun goes down and it gets dark it’s activated by the suprachiasmatic nucleus (SCN). The SCN functions like a clock and regulates a pattern of activities that affect the entire body. At first light each day the SCN delays the release of melatonin, increasing the body temperature and releasing cortisol to prepare us for the day. When the sun goes down and there is darkness SCN turns on the pineal gland to actively produce melatonin, this usually occurs around 9pm. You begin to feel less alert and ready for sleep. As the regulation of the circadian day-night rhythm occurs at night, synthesis and secretion of melatonin are stimulated reaching a peak value between midnight and 3am, secreted into the blood and cerebrospinal fluid.
Melatonin is referred to as the “Dracula of hormones” because bright light will inhibit the release of melatonin and will only come out in the dark. Even if the pineal gland is switched “on” by the body clock, it will not produce melatonin unless the person is in a dimly lit environment. This includes sunlight and artificial indoor lighting. During winter when the days are usually shorter and darker your body may produce melatonin earlier or later in the day which can throw off your natural sleep cycles. Being awake while it is light during the day relates to daylight, and sleeping at night when it is dark relates to darkness, this is the alternating cycle of sleep and waking. Most people have a 24-hour circadian rhythm, driven by light and darkness and every 24 hours you make a full cycle, going from being awake, to sleep, to awake again. People with insomnia tend to have lower nocturnal plasma melatonin levels.
Melatonin taken as a supplement can signal environmental darkness and management of circadian rhythm sleep disorders such as insomnia and delayed sleep-phase syndrome. Melatonin can significantly advance the phase of the sleep/wake rhythm by influencing promotion of sleep and regulate the sleep/wake rhythm. You may experience fatigue, reduced energy, mood changes and similar symptoms to seasonal affective disorder (SAD). Studies have shown melatonin dosage to shorten sleep latency (the time it takes to fall asleep) and reduced sleep fragmentation (staying asleep). Used also by shift workers and people suffering jetlag, melatonin improves sleep by resetting the biological clock. The main benefit of taking a melatonin supplement is to reinforce external cues for sleep and help shift sleep-wake rhythms. A serious condition known as Non-24-Hour Sleep-Wake Disorder (Non-24) where your circadian rhythm isn’t always matched up with daytime and night-time because your cycle is longer than 24hours. As a result, you go from being on the same sleep cycle as everyone else to slowly shifting your sleepiness later and later in the day. This disorder is often due to light not reaching a certain part of the brain, this mainly affects people who are totally blind. However, the symptoms of Non-24 can look similar to other sleep disorders so please refer to a sleep specialist for a diagnosis.
Important information regarding supplementation – In Australia you require a prescription from a Doctor to take melatonin as a sleep-inducing aid as it may negatively interact with different medications and needs to be taken in the correct recommended dose and time of day otherwise it may reset your biological clock in the wrong direction.