Several studies from the early 20th century have shown that human sleep consists of five stages. Four of these stages are known as non-REM stages, while the fifth stage is known as REM sleep. Each stage of sleep has distinct characteristics.
Stage 1:
During this stage, a person begins to feel drowsy. The eyes remain closed, and this stage typically lasts for 5 to 10 minutes. If a person is woken up from this stage, they may feel as though they haven’t slept at all. There is a 50% decrease in activity between wakefulness and stage 1 sleep.
Stage 2:
Stage 2 is a combination of periods of muscle tone and muscle relaxation. The body is preparing to enter into deep sleep during this stage. Body temperature gradually decreases, and heart rate slows down.
Stages 3 and 4:
These stages are considered deep sleep stages, with stage 4 being deeper than stage 3. They are also referred to as slow-wave or delta sleep. Electromyogram records show rhythmic stability and a prototype of deep sleep during these stages.
Non-REM Sleep:
Non-REM sleep consists of stages 1-4 and lasts a total of 90 to 120 minutes, with each stage lasting 5 to 15 minutes. A normal sleep pattern should include the following stages: 1, 2, 3, 4, 3, 2, REM.
Stage 5:
Stage 5 is REM sleep, also known as Rapid Eye Movement sleep. Heart rate and respiration rate increase and become irregular during this stage. Intense dreams occur, but the major voluntary muscle groups become paralyzed, preventing a person from acting out their dreams. This stage begins with 10 minutes and gradually lengthens.
REM disorder is a type of parasomnia characterized by intense, violent dreams that a person may try to act out. This can be followed by shouting, grunting, and sleepwalking. If this continues for an extended period, it can have damaging effects on a person’s mental and physical well-being and may require medical advice. It is recommended for a person to get at least 6 to 9 hours of uninterrupted sleep. Lack of proper sleep can result in tiredness, decreased productivity, and irritability throughout the day.
The human ear can hear sounds ranging from 20Hz to 20,000Hz, while the frequencies of human brain waves are below 40Hz. Binaural beats or tones are produced in the brain when binaural sound with a frequency of 40Hz is used. Studies have shown that binaural beats can induce relaxation, improve focus and attention, and alter states of consciousness. These beats are perceived by the brain without any physical stimulation. Binaural beats affect the brain through the entrainment of brainwaves, a phenomenon discovered by Heinrich Wilhelm Dove.
Different individuals react differently to various sounds. For those who dislike pure sine waves, mixing in pink noise or natural sounds like the sound of a river can be helpful. It is generally advisable to keep the volume low to enhance the effectiveness of binaural beats. In simple terms, binaural beats lower brain frequency, aiding relaxation and promoting a solid night’s sleep, resulting in a refreshed feeling upon awakening in the morning.
