Stages of sleep: What those 7-9 hours actually mean
Sleep scientists divide sleep into five stages. But, for simplicity’s sake, the wearables by World of PLAY categorise it into light, deep and total sleep. The groups of light and deep sleep cover all the five stages in the following manner:
1. Light sleep
Light sleep is the most important part of sleep and it comprises two stages:
· Stage 1 –
This is the beginning of the sleep period. The eye movements become slower. The brain begins to produce alpha and theta waves signifying the body and brain are at rest. But the mind is still awake during this period of 5 to 10 minutes. The slightest disturbance or noise can wake you up during this stage. If you happen to get up, you will feel that you haven’t slept well.
· Stage 2 –
This second stage makes your body go into a deeper state of relaxation. Studies show that it roughly makes up for most of the sleep cycle. During this period, your body temperature drops. Even the heart and respiration rates become slow. This time gives rise to what sleep researchers call sleep spindles. These bursts of electricity in the brain assist in memory retention and learning.
2. Deep sleep
Deep sleep is the time when your body doesn’t move. It comprises three stages as mentioned below:
· Stages 3 & 4 –
These two stages are clubbed together. Their scientific term is slow-wave sleep. During this time, the body goes into the repair mode. It produces growth hormones, normalises the immune system and replaces cells. These restorative sleep stages go for two hours for those under 30 years of age. The slow-wave sleep time gradually shortens with increasing age.
· REM –
Abbreviated to Rapid Eye Movement, REM is your sleep’s final stage. During this period, eye movements, heart rate and brain waves are faster. But, there is no voluntary muscle activity. Dreams occur in this state.
Thanks to PLAYFIT SW75, PLAYFIT 21 and PLAYFIT 53, now each stage of sleep is quantifiable. The accurate data you get can tell you much about your daily mood and physical health. If the statistics confuse you a little, allow us to help you understand them better.
The sleep cycle sequence
Every night you sleep, each of the abovementioned stages cycles four to five times. They don’t end with the REM sleep stage.
Once you get into bed, your body goes into Stage 1. It can take some seconds or minutes to get into this stage. After a few minutes, Stage 2 occurs for 10 to 25 minutes. Following it is Stage 3, which roughly continues for a few minutes. Stage 4 continues for 20 to 40 minutes. Before REM sleep is attained, stages 2 and 3 continue again. In the first sleep cycle, you get 10 minutes of REM sleep. After that, the body goes back to Stage 2. The REM sleep becomes longer with each cycle.
How you should use the sleep pattern data
The total sleep data in our PLAYFIT SW75 activity tracker is a summation of all the sleep stages in alternating cycles. Roughly 50- 65% is spent on light sleep stages and 15-25% on deep sleep. About 20 – 35 % is spent on REM sleep.
If you are not getting enough light or deep sleep, you will know instantly from the analysis. This can help you bring some necessary changes to your sleep cycle.