Health at Rest
Sleep is vital to the physical and psychological health. Physically, it is during sleep that we recover energy, regenerate our cells and restore our immune system.
Psychologically, it is extremely important too. The loss of sleep compromises the ability to perform all activities involving memory, learning, logical reasoning and mathematical calculation. Besides that, it also undermines the professional and personal relationships, leading to failures and errors during daily activities. It is therefore crucial to provide the best quality of rest for body and mind.
Sleep problems, even if sporadically, make everyday tasks more gruelling and undermine our productivity. What matters, in addition to the amount of hours slept, is the quality of sleep.
The REM (rapid eye movement) is characterized by physically relaxedness, that is, the functional paralysis of skeletal muscles.
In this phase, the brain activity is similar to wakefulness. Studies show that it is at this stage of sleep that most dreams occur. During this phase, the brain regions used for learning and organizing information are encouraged and the memory is strengthened. This makes this phase of REM sleep decisive for our daily performance.
This phase represents 20 to 25% of sleeping time, considering eight hours of sleep. It is an essential phase because it is during this time that the healing of body and mind occurs. This is crucial to achieve the best physical and psychological performance.
The non-REM sleep occupies about 75% of sleeping time and it is divided into four distinct periods known as period 1 (light sleep), period 2 (intermediate sleep) periods 3 and 4 (deep sleep and repair).
A sleep cycle lasts about ninety minutes with four to five cycles occurring over a period of a night sleep. During sleep, we usually go through repeated cycles, starting with phase 1 non-REM sleep, progressing to the fourth phase, returning to phase 2, and entering into REM sleep.
When back again to phase 2 the whole cycle repeats again. In the first sleep cycles, periods of non-REM (more specifically phases 3 and 4) have a longer duration than REM. As sleep progresses, phases 3 and 4 begin to shorten and the REM period begins to increase. The first part of sleep is predominantly non-REM. REM periods are longer lasting in the second half.