Melatonin is a hormone which is produced by the pineal gland in our brain from serotonin. It was only discovered in 1958. Melatonin regulates our circadian rhythm, thus influencing biological functions in the course of 24 hours like sleep, blood pressure, cortisol production etc. As soon as light shines onto the retina in our eyes the production of melatonin is inhibited. Darkness as opposed stimulates melatonin production. Therefore melatonin levels rise at night. This sleep promoting hormone reaches peak levels about three hours after midnight. Then they fall again. Melatonin also has an annual rhythm. Short days in winter cause higher levels during daytime than in summer. The consequence can be sleep disorders, tiredness and SAD (seasonal affective disorder). Melatonin works as the internal body clock. The system can be disrupted by e.g. artificial illumination, electromagnetic energy, exercise, seasonal changes, long haul flights, shift work, impairment in methionine metabolism, aging and in blind people. Relaxing sleep is also very important for our memory. If our sleep is disturbed by low melatonin levels this will also influence our cortisol levels and stress resistance. Melatonin imbalances have been associated with a wide array of health problems, including:
- Sleep disorders
- Depression
- Seasonal Affective Disorder (SAD)
- Chronic progressive multiple sclerosis
- Menstrual irregularities
- Mental health problems
Sampling is performed immediately upon awakening, usually between two and three in the morning. Only one tube is filled with a sample. The same sample is also used to measure cortisol. In the case of night waking, the melatonin level is often very low, but a high cortisol level for that time of the night can also cause people to wake up during the night.
