Deep Sleep vs REM Sleep: What Each Stage Does
Quick Answer: Deep sleep (slow-wave sleep) is the hardest stage to wake from and comes mostly in the first third …
Sleep Blog
The Sleep Calculators Online blog covers sleep science, sleep health and practical ways to sleep better. Articles explain how sleep stages and REM sleep work, why trouble falling asleep and waking at night happen, how your body clock shapes when you feel sleepy, and what sleep disorders such as sleep apnea, narcolepsy and restless legs look like.
Updated articles link to the research and health sources behind them, and many pair with a free tool such as the bedtime calculator, the sleep cycle calculator or the sleep debt calculator.
Looking for something specific? Browse sleep guides by topic, all sleep calculators or our pillow reviews. The newest articles are below.
Stages Of Sleep Deprivation: What 24 To 72 Hours Does
Quick Answer: Sleep deprivation gets worse in steps. After 17 to 19 hours awake, reaction and accuracy can match a …
What Is Sleep Pressure? How Your Body Builds Sleepiness
Quick Answer: Sleep pressure is the build-up of the need for sleep the longer you stay awake. It works alongside …
What Is Deep Sleep? Stage N3 Explained Simply
Deep sleep is the third and deepest stage of non-REM sleep, also called stage N3 or slow-wave sleep. The Sleep …
How To Recover From An All-Nighter: A Next-Day Plan
Quick Answer: After an all-nighter, do not drive while drowsy. Nap no more than 20 minutes, keep caffeine under the …
Signs Of Sleep Deprivation: Symptoms To Watch For
The most common signs of sleep deprivation are trouble focusing, a short temper, daytime sleepiness and slower reactions. The NHLBI …
How To Recover From Sleep Debt And How Long It Takes
You can recover from sleep debt, but it usually takes days, not one long sleep-in. Sleep debt is the gap …
PTSD And Sleep: Nightmares, Insomnia And What Helps
Quick Answer: Sleep problems are close to universal in PTSD. In a national survey, more than 92 percent of people …
Sleep And Depression: How The Two Are Linked
Quick Answer: Sleep and depression are tightly linked in both directions. A meta-analysis of 21 studies found that people with …
Alcohol And Sleep: Why It Harms Rest And What Helps Instead
Alcohol does not help you sleep. It can make you drowsy for a short time, but it disrupts REM sleep …