Melatovit

Circadian rhythms are internal biological rhythms with a periodic nature that manifest with a 24-hour interval. The most important is the sleep-wake cycle. In circadian rhythm disorders the quantity and quality of sleep is normal, but they occur at the wrong time according to usual schedules.

Several studies have shown that volunteers who were deprived of sleep for four to five hours for a few days, experienced altered neurocognitive, behavioural, metabolic, cardiovascular and immune parameters, as well as those related to vital functions.

What are the stages of sleep?

Sleep is characterised by two periods:

Slow, orthodox or non-REM sleep (REM: rapid eye movement) which is determined by four stages one after another, and may fluctuate during the same night:

• Stage 1 – drowsiness. It is observed immediately after vigilance and lasts for a few minutes. Muscle tone is somewhat lower than during wakefulness and eye movements are slow and occur intermittently.
• Stage 2 – “light” sleep. Brain activity in wakefulness decreases and slight awakening may occur.
• Stages 3 and 4 – strictly speaking, slow and deep sleep where there is already a continuous predominance of slow waves in brain activity, being more abundant in the middle of the night.

Paradoxical or activated, or REM sleep where there is a high activity of brain waves similar to those when you are awake. This is the reason of rapid eye movement and does not involve awakenings, as there is a noticeable reduction or complete loss of muscle tone during which there additionally are sudden muscle jerks.

What is REM sleep?

This stage of sleep represents 20% of our sleep cycle, that is, it lasts between 15 and 30 minutes. The name “rapid eye movement” is due to the constant movement of the eyeballs under the eyelids. This stage is characterised by high brain activity, similar to that one while we are awake, or changes in breathing and heart rates, although muscles are blocked. This is the stage in which we’ve got dreams and we can process the information accumulated during the day. Furthermore, if we wake up right during this stage it’s possible to remember what we were dreaming of.

What is melatonin and what is it used for?

Melatonin is a hormone produced by our brain and is secreted only during the dark hours of the day-night cycle. This hormone isn’t stored, but released once produced and is related to the process of induction of sleep and internal synchronisation of the circadian rhythm. Its regulation is carried out by the amount of light that reaches our eyes’ retina. The production of melatonin is influenced by factors like age (more abundant in children), the season of the year (in summer melatonin is secreted earlier and in winter it’s delayed), the menstrual cycle, stress or doing sport, daily time of sun exposure, some drugs such as benzodiazepines or beta blockers (a type of antihypertensive drugs), and even some conditions (in case of liver cirrhosis, for example, the production of melatonin is decreased).

What are the benefits of melatonin?

There is nowadays growing interest about the use of this hormone in circadian rhythm disorders such as jet lag syndrome (long flights), change of work shifts (night/day shifts) and sleep disorders in the elderly. It’s been shown that the intake of melatonin favours sleep onset, as well as continuing sleeping during rest hours, what additionally helps wake up without lethargy and not to interrupt, therefore, our daily activities.