What’s really happening under the sheets?
We all know a good night’s sleep is important, but have you ever wondered what’s happening to your body and brain while you’re snoozing? It’s easy to think of sleep as a time when your body and mind shut down, but in reality, this is far from the truth.
You normally go through 4 to 6 full sleep cycles every night. Each cycle is made up of four stages: awake, light, deep and REM sleep, and every stage is essential to your overall health and wellbeing in specific ways.
Stage one – The transition from wakefulness to sleep
When you first close your eyes, you’re in the lightest sleep stage, just long enough for you to drift off. Typically lasting between 1 and 7 minutes, this is when your brain activity starts to slow, muscles begin to relax, and you prepare for sleep. You’re not fully asleep yet and you can be easily woken.
Stage two – Light sleep
This is the stage before you enter a deep sleep, making up the largest percentage of total sleep time and typically lasting 10 to 25 minutes. Your muscles relax, body temperature falls, and your heart rate and blood pressure slow. Similarly, brain activity decreases, but there are short bursts of activity that prevent you from being woken up.
Stage three – Deep sleep
The deep sleep stage makes up 20-25% of total sleep, lasting 20-40 minutes and making it harder to wake someone up. Brain activity, breathing and heart rate slow further, whilst the blood supply to your muscles increases. Growth hormones are released to build and repair bone, muscle and tissue. Experts believe this stage is critical for restorative sleep, promoting bodily recovery, growth and hormone regulation.
Stage four – REM (rapid eye movement) sleep
During REM sleep, heart rate and blood pressure increase to levels similar to when awake. At the same time, your muscles are temporarily paralysed, apart from your eyes and muscles that control breathing. Even though your eyes are closed, they are still moving quickly, hence the name! Lasting 10-60 minutes and making up 20-25% of your sleep, REM sleep is essential for memory consolidation, emotional processing and brain development.
Sleep stages allow the brain to recuperate, consolidate memories, improve cognitive performance and enhance overall mental health. Equally, sleep is vital for the body, helping you maintain a healthy weight, support a strong immune system and improve heart health.