Exploring the Stages of Sleep: Understanding the Sleep Cycle
Sleep is an essential part of life for humans, and yet many overlook its importance. By understanding the sleep cycle and stages of sleep, we can regulate healthy sleep patterns, and in turn improve our overall mental and physical health.
Sleep can be divided into two parts: non-REM (Rapid Eye Movement) sleep and REM sleep. Non-REM sleep is divided into three stages, with each lasting between 5 to 15 minutes. REM sleep has its own distinct stage that is longer and happens every 90 minutes during sleep.
The five stages of sleep, from shallowest to deepest, are Stage 1, Stage 2, Stage 3, Stage 4, and REM sleep. Each stage has its own physiological characteristic for our body to go through, and the four deeper stages are known as “slow wave sleep”. To get the most out of our rest each night, it is important to cycle through each stage of the sleep cycle.
The First Two Stages of Sleep
Stage 1 of the sleep cycle is the lightest and consists of other shorter, light sleep. During this stage, our body and mind prepares for deeper sleep. It’s during this stage where we may experience hypnic jerks, or sensations where our body jerks awake.
Stage 2 of the sleep cycle is the next deep sleep where our body temperature drops further and heart-rate slows. During this stage, we may experience brief and sporadic bursts of delta waves. Delta waves are high amplitude brain waves associated with deep sleep.
Stages 3 and 4: Deep, Slow Wave Sleep
As we enter Stage 3 and 4 of the sleep cycle, we experience deep sleep where it becomes difficult for us to wake up. Our breathing and heart-rate slow down, and EEG waves show added frequency and amplitude. During these stages, cells in our body revive and refresh themselves while hormones are released for repairing and recovery.
Stage 3 is a transitional stage between light sleep and the deeper stages. This is the stage when sleepwalking, bedwetting, and night terrors may occur. Stage 4 is the deepest stage in which our body does most of its repairing and recovering. It is during this stage where a person who is sleep deprived may experience “catch-up sleep”, and can sleep very deeply.
After Stage 4, we return to Stage 3 and then to Stage 2 before entering REM sleep.
REM Sleep: Dreaming and Memory Consolidation
REM sleep is the fifth and final stage of the sleep cycle. As we progress through this stage, our eyes jerk rapidly as our heart rate, breathing rate, and blood pressure increases to levels similar to when we are awake. During REM sleep, we can experience vivid and sometimes lucid dreaming. The brain is also very active during this phase, triggering hormones that allow us to process events of the day and store memories.
Benefits from a Healthy Sleep Cycle
- Acquiring better problem solving skills
- Enhanced creativity
- Reduction of stress, inflammation, and depressing symptoms
- Better memory, focus, and attention span
- Improved physical health
Conclusion
By understanding the stages of sleep and what’s happening in each within our body, we can predict our energy levels, mood, and other important aspects of our daily life. Quality sleep can help improve our cognitive performance, prevent accident risks, enhance creativity, and help keep us healthier overall.