REM vs. Deep Sleep: How to Tell if You're Getting Quality Sleep

Getting quality sleep isn't as simple as it sounds. If you experience grogginess and fatigue even after hours of sleep, it indicates that you might not be getting enough of the quality sleep you need to feel refreshed and rejuvenated. Thankfully, there are ways to evaluate how good -- or bad -- your sleep patterns are.

Modern gadgets like sleep trackers, smart rings, smart beds and other wearable devices make it possible to get pretty accurate sleep diagnoses. Read on for a breakdown of sleep cycles to help you better understand them. 

Read more: I Went to Sleep With a Robot to Get Better Sleep. This Is What Happened

What are sleep cycles?

Humans sleep in cycles. The best known is REM, which stands for rapid eye movement because your eyes move rapidly during this stage of sleep. Scientists and researchers generally divide the cycles into two ...