How to Sleep Better After 40: Every Habit Ranked by Evidence

Four free moves you can run tonight for better sleep. The habits that matter most depend on your chronotype. Watch the video and read the full protocol to understand the science behind it.

Get Started - Find your Chronotype

Or watch the full video first →

Most sleep advice costs $200. Everything that works is free.

The four free moves that do most of the work.

Steaming coffee in a rustic mug on a marble table with a spoon and napkin.

Last caffeine by noon

Caffeine half-life is 5–6 hours. A noon coffee is still 25–50% on board at bedtime. The Drake 2013 study lost subjects an hour of sleep when caffeine was 6 hours pre-bed

Source: Drake 2013, J Clin Sleep Med

Smart thermostat on a wall displaying temperature settings at 68 degrees.

Bedroom under 70°F

Your body has to drop core temperature two degrees Fahrenheit to initiate sleep. If the room is too warm, the drop never happens cleanly

Source: Okamoto-Mizuno 2012, J Physiol Anthropol

Digital clock showing 9:00 PM on a wooden surface next to a bed.

Same time. Seven days a week

Your circadian rhythm doesn't know it's Saturday. Bouncing your schedule on weekends costs you a Monday version of jet lag.

Source: Roenneberg 2003, J Biol Rhythms

Dark bedroom with a bed and nightstands.

Dark room

Blackout curtains, no bedside lamp, no bathroom light visible. Light in the second half of the night degrades melatonin in ways you don't feel and don't notice.

Source: Walker, Why We Sleep, 2017

Woman sleeping peacefully under white bedding with a tattoo on her arm.

Two people sleeping under a gray comforter on a bed in a dimly lit room.

Sleep is the Master Cheat Code.

Every other health habit you're grinding on (training, nutrition, focus, stress regulation) performs better or worse depending on what happened the night before. This is why getting the right sleep is so important.

Under-sleep doesn't feel like under-sleep. Van Dongen restricted people to six hours a night for two weeks. By the end, they had cognitive impairment equivalent to two nights of total sleep deprivation. The cruel part: they didn't notice. → Van Dongen 2003, Sleep journal

Walker's framework is right. His bigger numbers don't all hold up. We cite Walker for the framework. For specific claims we go to the original papers. → See full citation library below

Sleep is officially a cardiovascular risk factor. The American Heart Association formally classified short sleep as a CV risk factor on par with blood pressure in 2016. The Mendelian randomization study in 2019 confirmed it's causal, not just correlated. → StOnge 2016 + Daghlas 2019

Cancer and sleep is more nuanced than usually presented. The strong evidence is for shift work specifically — IARC classified it as a probable human carcinogen in 2010 and reaffirmed in 2019. The broader "less sleep causes cancer" claim is much weaker. → IARC 2019, Lancet Oncology

Polyphasic sleep was a fad. The 2021 National Sleep Foundation expert panel found polyphasic patterns are associated with worse health outcomes than normal sleep. → Section 5 — The honest landscape (takeaways) Weaver 2021, Sleep Health

True genetic short sleepers exist in under 1% of the population. If you think you do fine on five hours, statistically you almost certainly don't. → He 2009, Science

Magnesium glycinate is the supplement worth trying. The rest of the supplement aisle has modest-at-best effects. We cover them all in the protocol PDF. → Mah & Pitre 2021, BMC Complement Med Ther

SageMD Calm magnesium supplement bottle on a transparent background

Does magnesium help you sleep? Glycinate vs citrate

Brent supplements his health gaps to achieve better sleep. Magnesium glycinate is the main driver, but here is the rest of the supplements on his shelf that he uses along with his dose and timing.

Feature	Verdict	Dose & timing	Duration / cycling	Brand
Magnesium glycinate	Tier 1 - start here	200–400mg, 30–60 min before bed	Nightly, no cycling	Sage
Glycine	Tier 1	3g powder, before bed	Nightly, no cycling	Thorne / Pure Encapsulations
L-theanine	Tier 1 - for an anxious mind	200mg (Suntheanine), before bed	Nightly, no cycling	Thorne / Pure Encapsulations
Phosphatidylserine	Tier 2 - cortisol 3 AM wake-up	300–600mg with dinner	Ongoing, no cycling	Thorne / Pure Encapsulations
Ashwagandha	Tier 2 - chronic stress	300–600mg/day, evening	Cycle: 8–12 weeks on, 2–4 off	Pure Encapsulations (KSM-66/Sensoril)
PharmaGABA	Tier 2 - anxious onset	100–250mg before bed	As-needed or nightly	Thorne
Tart cherry	Tier 2	1oz concentrate before bed	Nightly, no cycling	Sports Research
Melatonin	Tier 2 - travel only	0.3–1mg, NOT 5–10mg	Situational, not nightly	Pure Encapsulations 0.5mg
Apigenin	Tier 3 - skip-ish	50mg before bed	Nightly, no cycling	Any third-party-tested
Valerian	Tier 3 - skip	300–600mg extract	Cycle if used (tolerance)	---
Chamomile / lemon balm	Tier 3 - very mild	Tea	---	---
5-HTP	Tier 3 - caution	50–100mg	---	Not with SSRIs

Some links in this section are affiliate links. If you buy through them, Sage may earn a small commission. We only link to products Brent actually uses or has tried. It doesn't change the price you pay.

Feature	Verdict	Dose & timing	Duration / cycling	Brand
Magnesium glycinate	Tier 1 - start here	200–400mg, 30–60 min before bed	Nightly, no cycling	Sage
Glycine	Tier 1	3g powder, before bed	Nightly, no cycling	Thorne / Pure Encapsulations
L-theanine	Tier 1 - for an anxious mind	200mg (Suntheanine), before bed	Nightly, no cycling	Thorne / Pure Encapsulations
Phosphatidylserine	Tier 2 - cortisol 3 AM wake-up	300–600mg with dinner	Ongoing, no cycling	Thorne / Pure Encapsulations
Ashwagandha	Tier 2 - chronic stress	300–600mg/day, evening	Cycle: 8–12 weeks on, 2–4 off	Pure Encapsulations (KSM-66/Sensoril)
PharmaGABA	Tier 2 - anxious onset	100–250mg before bed	As-needed or nightly	Thorne
Tart cherry	Tier 2	1oz concentrate before bed	Nightly, no cycling	Sports Research
Melatonin	Tier 2 - travel only	0.3–1mg, NOT 5–10mg	Situational, not nightly	Pure Encapsulations 0.5mg
Apigenin	Tier 3 - skip-ish	50mg before bed	Nightly, no cycling	Any third-party-tested
Valerian	Tier 3 - skip	300–600mg extract	Cycle if used (tolerance)	---
Chamomile / lemon balm	Tier 3 - very mild	Tea	---	---
5-HTP	Tier 3 - caution	50–100mg	---	Not with SSRIs

Diagnose your sleep problem.

Onset — "I can't fall asleep"

The lying-in-bed-staring-at-the-ceiling kind. Check, in order:

Caffeine cutoff at noon (most common cause)
Bedroom temperature under 70°F
Phone in another room an hour before bed
4-7-8 breathing (inhale 4 sec, hold 7, exhale 8 — three cycles) for racing-mind onset
Brain-dump on paper if it's open work loops
Move dinner earlier and lighter if late eating
Move training earlier if you're sensitive to late workouts

Supplements specifically for onset:

Magnesium glycinate (most evidence-backed)
L-theanine (specifically for anxious arousal)
Low-dose melatonin 0.3mg (circadian shift only, not nightly)

The CBT-I move: if you've been in bed 20 minutes and can't sleep, get up. Sit in dim light, read something boring, return when sleepy. Breaks the bed-equals-awake association. If onset issues are a multi-week pattern, that's chronic insomnia. CBT-I is your answer. See the "If you have chronic insomnia" section below.

Maintenance — "I wake up at 2 AM and can't get back to sleep"

The 2 AM ceiling stare. Check, in order:

Alcohol within 4 hours of bed? Stop entirely. #1 cause in the general population.
Heavy dinner late? Move dinner 3+ hours before bed, make it lighter.
Room warming up overnight? Adjust HVAC schedule.
Stress / rumination? Don't reach for the phone, don't watch the clock. Try 4-7-8
breathing first. If not back asleep in 20 minutes, get up, dim light, boring book, return when sleepy

Supplements specifically for maintenance:

Phosphatidylserine 300–600mg with dinner (if cortisol-driven wake-up — high-stress
day, 3 AM wake)
Ashwagandha 300–600mg evening (if rumination-driven)
Magnesium glycinate (modest help, same dose)

If maintenance issues happen 3+ nights/week for 3+ months, you have chronic insomnia. See the "If you have chronic insomnia" section.

Watch for apnea. Heavy snoring + waking up gasping + morning headaches = sleep study.
Don't wait.

Architecture — "I sleep the hours but the quality is off"

This is the wearable-revealed problem. Most people don't know they have it until the data shows them.

If your deep sleep is low (under ~60 min for adults):

Deep sleep is concentrated in the first half of the night. The compressors:

Alcohol — especially crushes early-night deep sleep. Cut it.
Late workout — body temp still up at bedtime. Move training earlier.
Heavy late dinner. Move earlier or lighter.
Room too warm in the first 2 hours of the night.
High evening cortisol / stress.

Supplements: magnesium glycinate, glycine 3g, apigenin 50mg (limited evidence). None are transformative on their own.

If your REM is low (under ~90 min for adults):
REM is concentrated in the back half of the night. The compressors:

Alcohol massively suppresses REM. Single biggest variable.
Cutting sleep short — waking at 5 AM instead of 7 costs most of your REM.
SSRIs and some other medications suppress REM. Talk to your doctor.
Irregular schedule.
Chronic high stress.

Supplements: honestly, none. The levers for REM are alcohol elimination and full sleep duration. Don't supplement your way past those.

If both are low: general sleep deprivation pattern. Lock the A-tier and B-tier from the
protocol. Test for apnea if symptoms warrant. Give it 2–4 weeks.

Deep sleep: the habits that move it

Woman lying on a bed with her eyes closed, and hand on forehead not feeling well.

Deep sleep: the habits that move it

Your bedtime is 50% genetic. What's your chronotype? 2-minute quiz

351 genes decide when you get tired and determine your chronotype. So why are you still fighting them.

The different Chronotypes:

The Lark. About 40% of adults. You've never once needed your alarm. Your best thinking happens before anyone else is awake. By 9:30pm you're negaotiating with gravity.
The Owl. About 16% of adults. It's 11pm and you just found your second braind. At 8am, your reaction is 8% slower than a lark's. At 8pm you win.
The In-Between. About 44%. You can fake either. Which is why you ever learned which way your cloc leans, and your sleep pays for the guess.

Fighting your type has a name: social jet lag. Over 70% of us live with at least an hour of it. The same clock-shift as flying to Denver, every single week.

Stop fighting your type, understand it to know when to time caffeine, when your bedtime is, and when to start winding down.

A woman with curly blonde hair sleeping soundly in bed, covered by white pillows and a white duvet.

Get the version of this protocol that fits your wiring.

Brent's a morning lark. His 5:30 AM wake-up matches his biology. If yours is different, the principle still applies,same time every day, just a different time. Take the quiz and we'll send you a personalized PDF based on whether you're a morning lark, a night owl, or somewhere in between.

Five questions. Less than a minute. No "right" answer.

Quiz based on the reduced Morningness-Eveningness Questionnaire, developed by Adan & Almirall (1991) from the original by Horne & Östberg (1976). Used here for educational purposes.

Couple lying in bed together in a bedroom setting.

Sleep on Easy Mode

Couples whose clocks match report better sleep AND a better sex life than couples whose clocks don't.

Take the 60-second chronotype quiz and compare results.

Check out our other Protocols

A floating booklet titled "The Lab-Reading Cheat Sheet" by Sage.

Read Your Own Labs.

The Lab-Reading Cheat Sheet I wish I had when I was younger. Every marker on a standard panel explained. Every marker your standard panel is missing. And how to read the trend that actually matters more than any single number. Understand how to read your labs and understand where your health is at.

How to read your lab results →

A woman with long brown hair and round black-rimmed glasses holding a green pen and looking down at her notebook studying.

Learning How To Learn

School expected you to learn and never covered how learning actually works. There are four moves that actually build a skill, and all four have decades of research behind them: retrieval practice, spaced practice, interleaving, and desirable difficulty.

Learn how to learn →

Every study cited in the video.

Thirty-eight peer-reviewed papers. Every claim Brent makes on camera has one of them behind it. Pull the abstract, read the methods, decide for yourself.

Dawson D, Reid K. Fatigue, alcohol and performance impairment. Nature. 1997;388(6639):235.
Williamson AM, Feyer A-M. Moderate sleep deprivation produces impairments in cognitive and motor performance equivalent to legally prescribed levels of alcohol intoxication. Occup Environ Med. 2000;57(10):649–655.
Van Dongen HPA, et al. The cumulative cost of additional wakefulness: dose-response effects on neurobehavioral functions and sleep physiology from chronic sleep restriction and total sleep deprivation. Sleep. 2003;26(2):117–126.

Cappuccio FP, et al. Sleep duration predicts cardiovascular outcomes: a systematic review and meta-analysis of prospective studies. Eur Heart J. 2011;32(12):1484–1492.
Yin J, et al. Relationship of sleep duration with all-cause mortality and cardiovascular events: a systematic review and dose-response meta-analysis. J Am Heart Assoc. 2017;6(9):e005947.
St-Onge MP, et al. Sleep duration and quality: impact on lifestyle behaviors and cardiometabolic health (AHA scientific statement). Circulation. 2016;134(18):e367–e386.
Daghlas I, et al. Sleep duration and myocardial infarction. J Am Coll Cardiol. 2019;74(10):1304–1314.

Lovato N, Lack L. The effects of napping on cognitive functioning. Prog Brain Res. 2010;185:155–166.

Weaver MD, et al. Adverse impact of polyphasic sleep patterns in humans: report of the National Sleep Foundation sleep timing and variability consensus panel. Sleep Health. 2021;7(3):293–302.

Adan A, Almirall H. Horne & Östberg morningness-eveningness questionnaire: a reduced scale. Pers Individ Dif. 1991;12(3):241–253. (The rMEQ used in the Sage sleep quiz. Original: Horne JA, Östberg O. Int J Chronobiol. 1976;4(2):97–110.)

Guzey A. Matthew Walker's Why We Sleep is riddled with scientific and factual errors. guzey.com, 2019.

Every claim in the video and the protocol traces to one of these papers. Pull the abstract, read the methods, decide for yourself. Where the evidence is thin or preclinical, apigenin, oral GABA crossing the blood-brain barrier, magnesium L-threonate for sleep, we say so rather than dressing it up.

*All information on this page is educational content, not medical advice. Always consult with healthcare professionals for medical advice.