The brain benefits of deep sleep -- and how to get more of it | Dan Gartenberg

A walk through the stages of sleep | Sleeping with Science, a TED series

Mastering the Art of Sleep: Finding the Perfect Balance of Deep, Light, and REM Sleep

What's REM Sleep - How Much Do You Need?

How much sleep do you really need? | Sleeping with Science, a TED series

Mayo Clinic Minute: What are the stages of sleep?

Stages of Sleep - non-REM, REM, Sleep Studies

Sleep stages and circadian rhythms | Processing the Environment | MCAT | Khan Academy

Sleep Time & Age

Are naps actually good for us? | Sleeping with Science

Why you're still tired after getting 8 hours of sleep

Sleep 5: Types of Sleep and Sleep Cycles

How many hours of sleep a night do I need?

Are you Getting Enough Deep Sleep?

How Much Deep, Light, and REM Sleep Do You Need

2-Minute Neuroscience: Sleep Paralysis

Study helps explain sleep problems in the elderly

How to Get More Deep Sleep!

The Danger of Sleeping Too Much

The Sleep Cycle: How It Works And Explaining The 4 Stages of Sleep!