Discover the details of the stages of the sleep cycle and how the body transitions between light and deep sleep, including the duration of rest needed based on age.
What are the stages of the sleep cycle?
While sleeping, a person goes through a series of different brain patterns and activities aimed at physical recovery and rest. This process is divided into two main types:
Non-Rapid Eye Movement (NREM)
Known as quiet sleep, this phase consists of three levels a person passes through before reaching deep sleep:
- Stage 1: A short transitional period lasting between 5 to 15 minutes. The person is in a light sleep state and is easily awakened. During these moments, heart rate and breathing slow down, muscles begin to relax, and alpha and theta waves are produced.
- Stage 2: This light sleep lasts up to 20 minutes. Body temperature drops, awareness of surroundings decreases, and heart rate and breathing become more regular as eye movement stops.
- Stage 3: This is the deep sleep stage (delta sleep), where the brain emits slow delta waves. In this phase, the body relaxes completely, blood pressure and breathing rates drop, and it is difficult to wake the sleeper. The body also repairs tissues, builds muscle and bone, and strengthens immunity.
Rapid Eye Movement (REM)
This active phase usually begins 90 minutes after the onset of sleep and can last for an hour. It represents about 25% of the total sleep cycle in adults, while it may reach half of the sleep duration in children. It is characterized by:
- Intense brain activity, information processing, and memory consolidation; this is the stage where most dreams occur.
- Rapid movement of the eyes under the eyelids.
- An increase in blood pressure and heart rate, with fast and irregular breathing.
- Temporary paralysis of the limb muscles.
How much sleep do you need?
The required hours of sleep vary by age group as follows:
- Birth to 3 months: 14 - 17 hours.
- 4 months to 11 months: 12 - 16 hours.
- 1 to 2 years: 11 - 14 hours.
- 3 to 5 years: 10 - 13 hours.
- 6 to 12 years: 9 - 12 hours.
- 13 to 18 years: 8 - 10 hours.
- 18 to 64 years: 7 - 9 hours.
- 65 years and older: 7 - 8 hours.
However, individual needs vary even within the same age group; some may feel rested after 7 hours, while others require at least 9 hours.
FAQ
What are the stages of the sleep cycle?
The process consists of NREM sleep (divided into three stages of increasing depth) and REM sleep, which is the active stage associated with dreaming and memory.
What are the stages of the ovarian cycle?
It consists of three main phases: the follicular phase, which begins with follicle formation; the ovulation phase, where the egg is released; and finally the luteal phase, which lasts about two weeks.
How can you protect yourself from silent diseases?
This can be done through periodic check-ups, such as screening for diabetes every 3 years for those over 45, checking blood pressure at least once a year, and monitoring the regularity of the menstrual cycle in women.
When should you visit a doctor?
You should consult a doctor immediately if the following signs appear:
- Menstrual cycle delayed by 35 days or more, or the appearance of excess hair on the face and body and acne.
- Noticing skin darkening (blue-black tint) in areas such as the elbows or behind the neck (especially with weight gain).
- If a blood pressure check shows a reading higher than 140/90 mmHg.
- Constant feeling of thirst, dry mouth, or blurred vision.
Disclaimer: This content is for informational purposes only and does not substitute for professional medical advice.
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Illustration: AI-generated
approved by: Medica Health team