Every article follows our editorial standards: sources from sleep medicine bodies, government health agencies and peer-reviewed research, calculations that match our free tools, and advertising kept separate from the writing.
Articles by Alex Giles (50)
- How Many Sleep Cycles Do You Need a Night?Most adults need 5 sleep cycles a night. Here's what happens in each cycle, why the last ones matter, and how to plan your night around them.3 min read
- How Much Caffeine Is in Your Drink? A Chart, Plus Your Cutoff TimeCaffeine in coffee, espresso, tea, soda and energy drinks side by side, plus the latest time to drink each one for a 10:30 PM bedtime.3 min read
- How to Wake Up at 5 AM (Without Feeling Awful)The bedtime you need for a 5 AM alarm, how to shift your schedule without wrecking your week, and the evening habits that make early mornings easier.3 min read
- Is 6 Hours of Sleep Enough? What the Research Actually ShowsSix hours feels fine to a lot of people. Research says it isn't, and that you're the last to notice. Here's what 6 hours does and how to get more.3 min read
- Is It Better to Sleep 1 Hour or Stay Up All Night?Short on time before an early flight or exam? Here's when a short sleep beats staying up, how long to sleep, and how to time the alarm.3 min read
- What Time Should I Go to Bed? A Bedtime Chart for Every Wake-Up TimeFind your ideal bedtime for any wake-up time from 4 AM to 10 AM, based on 90-minute sleep cycles. One chart, no math.3 min read
- What Time Should Kids Go to Bed? Bedtime Chart by AgeA simple bedtime chart for kids and teens by wake-up time, based on how much sleep children need at each age, plus tips for making bedtime stick.3 min read
- 12 Signs You Are Sleep Deprived (Even If You Feel Fine)Needing an alarm, falling asleep instantly, weekend lie-ins and afternoon crashes are common signs of sleep deprivation. Here's the checklist and what to do.3 min read
- 7 vs 8 Hours of Sleep: Which Is Better?Both are within the healthy range for adults. 8 hours gives more margin, but 7.5 hours often feels better because it ends on a full sleep cycle.3 min read
- A Bedtime Routine for Adults: The 60-Minute Wind-Down That Actually WorksA simple 60-minute bedtime routine for adults, minute by minute, with the reasoning behind each step and how to fit it into a busy night.4 min read
- Are You a Night Owl or an Early Bird? Chronotypes, and Whether You Can Change YoursYour chronotype is partly genetic and shifts with age. Here's how to tell which you are, how much you can change it, and how to work with it.4 min read
- Do Sleep Cycle Alarm Apps Work? An Honest Look at Smart AlarmsSmart alarms promise to wake you in light sleep. Here's how phones and wearables guess your sleep stage, how accurate they are, and what works instead.4 min read
- Does Green Tea Keep You Awake? Caffeine, L-Theanine and TimingOne cup of green tea has about 28 mg of caffeine, so it rarely wrecks sleep, but several cups or matcha can. Here's the latest time to drink it.3 min read
- Drank Coffee Too Late? How to Fall Asleep AnywayNothing flushes caffeine out faster, so the honest fix is to wait it out well. Here's how much is left, when it clears, and what actually helps tonight.3 min read
- Energy Drinks and Sleep: How Late Is Too Late?A 16 oz energy drink can hold about 160 mg of caffeine, enough to affect sleep even from a mid-morning can. See cutoff times by can size.3 min read
- How Long Does Caffeine Last? An Hour-by-Hour TimelineCaffeine has an average half-life of about 5 hours, so half a morning coffee is still in you at lunch. See the hour-by-hour timeline for a 95 mg cup.4 min read
- How Long Does It Take to Fall Asleep? What's Normal, Too Fast and Too SlowMost healthy adults fall asleep in about 10 to 20 minutes. Falling asleep in under 5 minutes, or regularly over 30, can be a sign something's off.3 min read
- How Much Sleep Do Athletes Need? What the Research SaysAthletes need at least 7 to 9 hours, and many do better with more. What sleep extension studies found, and bedtimes for 7.5, 9 or 10 hours in bed.4 min read
- How Much Sleep Do College Students Need? (And How to Get It in a Dorm)College students need 7 to 9 hours of sleep a night. Here's why most fall short, what all-nighters cost you, and how to sleep better in a dorm.3 min read
- How Much Sleep Do Older Adults Need? What Changes After 65Adults over 65 need about 7 to 8 hours of sleep. Here's how sleep changes with age, when naps help, and which sleep problems are worth a doctor's visit.4 min read
- How Much Sleep Do Teenagers Need? Hours, Bedtimes and Why Teens Stay Up LateTeens need 8 to 10 hours of sleep a night. Here's why their body clock runs late, and a bedtime table for every common school wake-up time.4 min read
- How Much Sleep Does a Toddler Need? Naps, Bedtimes and Sample SchedulesToddlers aged 1 to 2 need 11 to 14 hours of sleep a day, naps included. Sample schedules, when naps usually drop, and typical bedtime ranges.3 min read
- How to Go to Bed Earlier (and Actually Fall Asleep)Move your bedtime 15 minutes earlier every few days, fix your wake-up time first, and get morning light. A step-by-step plan that works.4 min read
- How to Nap at Work, in Your Car or on a BreakKeep it to 10 to 20 minutes, nap on your own break time, and time it for early afternoon. How to nap at work, in a car or on a shift, safely.4 min read
- How to Recover From an All-Nighter: The Next 24 to 48 HoursPulled an all-nighter? Get through the next day safely, then use one early night and a fixed wake-up time to get back to normal within a day or two.4 min read
- How to Sleep Before a Race: The Two-Nights-Before Rule and a Race-Eve PlanWhy the night two days before your marathon matters most, what bedtime to aim for before an early start, and what to do if nerves keep you up.4 min read
- How to Sleep Before an Exam (and Why the Week Before Matters More)How to sleep well before an exam: the bedtime to aim for, a night-before plan, and why your sleep over the whole week matters more than one night.4 min read
- How to Stop Hitting Snooze (and Actually Get Up)Set one alarm for the time you really get up, put it across the room, and fix the bedtime that's leaving you short. A step-by-step plan.3 min read
- Is 5 Hours of Sleep Enough? What It Does to You, and How to Get Through the DayNo. Five hours is about 2 hours short of what adults need, and effects build every night. Here's how to time a short night and recover from it.4 min read
- Is a 90-Minute Nap Too Long?Not usually. A 90-minute nap covers one full sleep cycle, so you tend to wake refreshed. Take it early in the afternoon so it doesn't hurt tonight's sleep.3 min read
- Is Decaf Coffee OK Before Bed? How Much Caffeine Is LeftDecaf still has about 2 to 15 mg of caffeine per 8 oz cup. One cup after dinner is fine for most people; several cups or decaf espressos add up.3 min read
- Is It Bad to Lie in Bed Awake? The 20-Minute Rule ExplainedLying awake for a long time can train your brain to link bed with being awake. How the 20-minute rule works and what to do when you get up.3 min read
- Is It Bad to Sleep In on Weekends? How Much Is Too MuchSleeping in up to about an hour on weekends is fine for most people. Much more than that shifts your body clock and makes Monday harder.4 min read
- Jet Lag From the US to Asia: How to Adjust to Tokyo and Other Big Time ShiftsTokyo is 13 to 17 hours ahead of the US. Here's why that often acts like a westward shift, how long it takes, and a plan for LA or New York.4 min read
- Jet Lag From the US to Europe: A Day-by-Day Plan for New York to London or ParisA concrete plan for New York to London or Paris: what to do 3 days before, on the flight, and each night after you land, with exact times.4 min read
- Pre-Workout Before Bed: Can You Train Late and Still Sleep?A stimulant pre-workout with 200 mg of caffeine at 6 PM still leaves about 107 mg at a 10:30 PM bedtime. Here are cutoff times and stim-free options.3 min read
- Time in Bed vs Time Asleep: Why 8 Hours in Bed Isn't 8 Hours of SleepTime in bed includes falling asleep and waking in the night, so it's always more than your sleep. How to work out the gap and what's normal.4 min read
- What Is a Good Bedtime for Adults?For most adults with a 6 to 7 AM alarm, a good bedtime is between about 10 and 11:15 PM. Here's how to find yours and the latest you should go.3 min read
- What Is REM Sleep? How Much You Need and What Cuts It ShortREM is the dreaming stage of sleep. Most adults get about 1.5 to 2 hours a night, mostly in the early morning. Here's what cuts it short.4 min read
- What Is Sleep Restriction Therapy? How It Works in CBT-ISleep restriction therapy treats insomnia by matching time in bed to the sleep you actually get. How it works and why to do it with a clinician.4 min read
- What Is the Best Time to Sleep and Wake Up?There's no single best time. The best sleep window gives you 7 to 9 hours, fits your body clock and stays the same every day. Here's how to find yours.4 min read
- What Is the Best Time to Take a Nap?The best time to nap is early afternoon, roughly 1 to 3 PM for a 7 AM riser, during the natural post-lunch dip. Find your nap window by wake-up time.3 min read
- What Time Should I Go to Bed If I Wake Up at 6 AM?For a 6 AM alarm, go to bed at 10:15 PM for 7.5 hours of sleep or 8:45 PM for 9 hours. Exact times adjusted for how fast you fall asleep.4 min read
- What Time Should I Go to Bed If I Wake Up at 7 AM?For a 7 AM alarm, go to bed at 11:15 PM for 7.5 hours of sleep or 9:45 PM for 9 hours. Plus an evening timeline that makes it realistic.3 min read
- What Time Should I Go to Bed If I Wake Up at 8 AM?For an 8 AM wake-up, go to bed at 12:15 AM for 7.5 hours of sleep or 10:45 PM for 9 hours. Tips for night owls and remote workers.3 min read
- What Time Should I Wake Up If I Go to Bed at 11 PM?If you go to bed at 11 PM, wake up at 6:45 AM for 7.5 hours of sleep or 8:15 AM for 9 hours. See how your usual alarm lines up with your cycles.3 min read
- What Time Should I Wake Up If I Go to Bed at Midnight?If you go to bed at midnight, wake up at 7:45 AM for 7.5 hours of sleep or 9:15 AM for 9 hours. What to do when your alarm is earlier.3 min read
- What Time Should I Wake Up? Chart by BedtimeFind the best wake-up time for any bedtime from 8 PM to 2 AM, based on 90-minute sleep cycles. For most adults, 5 cycles (7.5 hours) is the target.4 min read
- Why Do I Wake Up With a Dry Mouth? Common Causes and What HelpsWaking up with a dry mouth usually comes from mouth breathing, dry air, alcohol or medications. Here's how to find your cause and when to see a doctor.4 min read
- Why Is Jet Lag Worse Flying East? East vs. West, ExplainedFlying east is harder because your body clock resists running early. Here's why, plus how many days each direction usually takes to recover.4 min read