Compared to the tracking of our daytime activities, sleep monitoring is a little harder to grasp. The variations of intensity between walking and running are easy to understand, but what differentiates light sleep from deep sleep? This blog post lists 4 facts about sleep cycles and sleep stages, to give you the basic knowledge of sleep tracking.
Basic knowledge #1
Sleep scientists have identified two broad categories of sleep stages – Rapid Eye Movement Sleep (REM Sleep) and Non-Rapid Eye Movement Sleep (NREM Sleep). Until 2007, NREM Sleep was divided into 4 different stages. But that year, the American Academy of Sleep Medicine decided to merge the third and forth stages: there are now 3 kinds of NREM Sleep.
Basic knowledge #2
The stages of sleep can be identified using various techniques, among which the recording of EEG waves (electroencephalographic waves – also known as brain waves) and the monitoring of certain body data (movement, heart rate, respiratory rate, temperature). While the tedious EEG technique – the recording of electrical activity along the top of the head via dozens of electrodes on your scalp – is almost only used in clinical contexts, the more accessible sleep tracking technique involving body data analysis has become widespread.
Basic knowledge #3
Wrist-worn activity trackers like the Withings Pulse Ox and the Activité watches offer “Actigraphic sleep tracking” (the device tracks your body’s movements to identify the sleep stage you are in). Note that this technique can only tell the difference between “Awake”, “Light sleep” and “Deep sleep”. In this case light sleep consists of NREM Stages 1 & 2, while deep sleep is the same as NREM Stage 3.
Basic knowledge #4
On top of light and deep sleep, an advanced sleep tracking device like the Withings Aura which analyzes your heart and respiration rates in addition to body movements, is able to also identify REM Sleep. This is top notch sleep tracking!
– The Withings Sleep Survey: Interactive analysis of sleep patterns
– The recommended amount of sleep.
– Other sleep-related articles:
• The impact of Daylight SavingTime on sleep patterns
• The 4 different stages of sleep (NREM Stage 1, 2, 3 & REM Sleep)