Circadian Rhythm Sleep-Wake Disorders: The Complete Guide
Six types of circadian rhythm disorders explained by a sleep doctor - from delayed sleep phase to shift work disorder. Diagnosis, testing, and evidence-based treatments.
13 min read
Author
Dr. Rachel Stein
PhD sleep science, CBT-I practitioner, former 11-year insomniac
Sleep researcher and former chronic insomniac. After 11 years of lying awake, used CBT-I to retrain her sleep and now translates the science into guides for people still in the struggle.
Articles by Dr. Rachel Stein
Every Type of Insomnia, Explained: Which One Is Keeping You Awake?
Can't sleep? The specific type of insomnia you have determines the best treatment. Here's how to identify yours and what actually works for each.
13 min read
The Two-Process Model: How Sleep Is Actually Regulated
Discover how Borbely's two-process model explains why you can't fall asleep at noon but crash at 10pm. The science behind sleep pressure and circadian timing.
13 min read
Sleep Stages Explained: Your Brain's Nightly 4-Part Symphony
Understand N1, N2, N3, and REM sleep stages - what happens in each, why they matter, and how to optimize your natural sleep architecture for better rest.
16 min read
Sleep Restriction Therapy: The Counterintuitive Insomnia Fix That Works
Sleep restriction therapy forces you to sleep less to sleep better. Here's how this CBT-I technique rebuilds your sleep drive and ends chronic insomnia.
11 min read
Sleep Onset Insomnia: Why You Can't Fall Asleep and What Actually Works
Sleep onset insomnia affects millions who lie awake for hours. Learn the science behind why you can't fall asleep and evidence-based solutions that work.
20 min read
Sleep Medications: The Complete Prescription Guide for Chronic Insomnia
Evidence-based guide to prescription sleep aids: DORAs, Z-drugs, benzos, and off-label options. Dosing, side effects, and when each works best.
16 min read
Sleep Maintenance Insomnia: Why You Wake Up and Can't Get Back to Sleep
The science behind middle-of-night awakenings and evidence-based strategies to stay asleep through the night. From cortisol spikes to sleep cycle boundaries.
14 min read
Sleep Hygiene: The Complete Evidence-Based Guide
The 12 research-backed sleep hygiene rules that actually work. Learn what sleep science says about temperature, timing, and why hygiene alone won't fix chronic insomnia.
15 min read
Sleep Apnea: The Complete Guide to Signs, Diagnosis, and Treatment
Everything you need to know about sleep apnea signs, diagnosis, and treatment options. From CPAP to oral appliances, get expert guidance on managing OSA.
12 min read
Sleep and Hormones: How Your Endocrine System Depends on Rest
Discover how sleep directly controls testosterone, growth hormone, cortisol, and hunger hormones. One week of poor sleep drops testosterone 15%.
10 min read
Sleep and Brain Health: What Really Happens When You Don't Rest
Discover how sleep affects memory, emotional regulation, and Alzheimer's risk. Science-backed insights on the brain's nightly repair process.
12 min read
Shift Work Sleep: The Complete Survival Guide for Night and Rotating Shifts
Evidence-based strategies for 15M US shift workers to sleep better, stay alert, and protect long-term health. From light therapy to strategic napping.
13 min read
Relaxation Techniques for Sleep: Which Actually Work According to Science
Evidence-based review of relaxation techniques for sleep. Progressive muscle relaxation, body scan meditation, breathing methods - what works and what doesn't.
15 min read
Parasomnias: The Complete Guide to Weird Things That Happen in Sleep
From sleepwalking to REM behavior disorder, understand the strange things your brain does during sleep and when to worry about them.
14 min read
The Optimal Bedroom Setup for Sleep: Everything That Actually Matters
Transform your bedroom into a sleep sanctuary with evidence-based temperature, lighting, noise, and humidity guidelines that actually work.
12 min read
New Parent Sleep Survival: The Honest Guide to Sleeping With a Newborn
Evidence-based strategies for new parent sleep deprivation. Real solutions for the first year, not just "sleep when baby sleeps."
11 min read
Natural Sleep Aids: Evidence-Based Review of What Actually Works
Honest evidence review of natural sleep aids including magnesium, valerian, L-theanine, and more. See which supplements have real research backing.
11 min read
The Morning Sunlight Protocol That Actually Resets Your Sleep Clock
The science behind Huberman's morning light protocol and how 10-30 minutes of sunlight exposure can fix your sleep schedule naturally.
14 min read
Melatonin: The Complete Evidence-Based Guide to What Actually Works
The truth about melatonin dosing, timing, and effectiveness. Why 10mg gummies don't work and what the research actually shows about this misunderstood hormone.
16 min read
Mattress Buying Guide: How Your Sleep Position Determines Your Perfect Bed
Skip the overwhelm. This evidence-based mattress buying guide matches firmness, materials, and features to your actual sleep position and body type.
13 min read
Jet Lag Protocol: Direction-Specific Recovery Strategies by Time Zone
Evidence-based jet lag protocols for eastbound and westbound travel. Pre-flight preparation, in-flight strategies, and destination recovery timelines.
13 min read
Interpreting Your Sleep Data: What Actually Matters vs What to Ignore
Learn what sleep tracker metrics actually matter and which ones to ignore. Focus on trends over single nights for better sleep insights.
13 min read
How Sleep Trackers Actually Work: The Technology Explained
Sleep trackers use accelerometers, PPG sensors, and algorithms to infer sleep stages. Here's what's actually happening on your wrist and why it's not like medical testing.
16 min read
Exercise and Sleep: The Complete Guide to Working Out for Better Rest
How exercise affects sleep quality, timing that works, and the science behind why moving your body helps you rest better at night.
11 min read
Diet and Sleep: What to Eat (And Avoid) for Better Sleep
Evidence-based guide to foods that help and hurt sleep. Learn meal timing, sleep-promoting nutrients, and what to avoid for better rest tonight.
12 min read
Your Circadian Rhythm: The Complete Guide to Your Body's Master Clock
Understanding your circadian rhythm—the 24-hour biological clock that controls sleep, hormones, and energy. Science-backed insights from sleep medicine.
11 min read
Chronic Insomnia: The Complete Guide to Breaking the Cycle
Learn what chronic insomnia really is, why it persists, and evidence-based treatments that work. From the 3P model to CBT-I solutions.
14 min read
CBT-I: The Complete Guide to the Gold Standard for Insomnia Treatment
CBT-I has a 70-80% success rate for chronic insomnia. Here's the six-component breakdown, timeline, and how to access this evidence-based treatment.
14 min read
Caffeine and Sleep: Why Your 2 PM Coffee Still Keeps You Awake at Midnight
The definitive guide to how caffeine affects your sleep, from adenosine blocking to genetic variations. Plus the real cutoff time backed by research.
13 min read
Blue Light and Sleep: What the Science Actually Says About Your Screens
The research on blue light blocking glasses is mixed, but your phone's brightness matters more than you think. Here's what sleep medicine actually shows.
12 min read
Sleep Trackers 2026: Oura vs Whoop vs Apple Watch vs Fitbit Compared
Sleep medicine doctor compares Oura Ring Gen 4, Whoop 4.0, Apple Watch, and Fitbit against PSG accuracy. What trackers get right and wrong about your sleep.
12 min read