Guides to sleep, recovery and daily habits.
Plain answers to common questions, with the research behind them and a clear line between what a phone can measure and what it cannot.
Start with the question you have.
Each guide answers a common question, then explains what your own data can show and where the evidence stops.
Sleep calculator for midpoint and timing drift
Use this sleep calculator to find your sleep midpoint from bedtime and wake time. daygauge shows your sleep timing against your usual window.
Social jet lag is what happens when your schedule pulls sleep timing sideways
Social jet lag is the gap between biological timing and social schedules. What it means, how it is calculated and what to try.
A sleep regularity score is about timing consistency, not just hours
Sleep regularity looks at how consistent your sleep timing is. This guide explains it and how daygauge shows your sleep timing against your usual window.
What microplastics testing can and cannot show
Microplastics testing is emerging and limited. Learn what tests can show and what they cannot prove. daygauge does not test for microplastics.
A microplastics blood test is not the same thing as a personal health forecast
Microplastics blood tests are an emerging research area. This guide explains what the findings mean and why interpretation needs caution.
The best health data app turns daily signals into decisions
How to choose a health data app for Apple Health: readiness, habits, privacy and comparison with your own average.
The best Apple Health app explains the day behind the charts
A good Apple Health app compares your readings with your own baseline and explains what changed.
A life score app needs a number people can inspect
How the daygauge Life Index turns Apple Health movement, sleep and recovery into one daily number from 1 to 1000, compared with your own average.
A good health data app connects passive signals to daily decisions
How sleep, movement, recovery, places and habits fit together in one health data app, without medical claims.
Apple Health insights need baselines, context and confidence
How daygauge reads Apple Health sleep, movement and recovery summaries and compares them with your own average.
A habit tracker can show what your routines do to your readings
A habit tracker that shows your logged habits next to your sleep, movement and recovery from Apple Health. Your data stays on your iPhone.
A recovery score needs sleep, HRV, resting heart rate and your own baseline
How a recovery score can use sleep, HRV and resting heart rate against your own average, and how daygauge's readiness works.
How HRV fits into a readiness score
HRV is most useful when compared with your own baseline, alongside sleep and resting heart rate. This guide explains how daygauge uses it.
Sleep midpoint can matter even when total sleep looks fine
Sleep midpoint is the halfway point between falling asleep and waking. daygauge shows your sleep timing against your usual window.
A post-meal walk is an easy experiment to run on yourself
What post-meal walks may do for glucose, and how to log yours in daygauge next to your sleep and movement. daygauge does not read glucose data.
Circadian timing is about when you sleep, wake and get light
How sleep timing, time in daylight and routine timing relate to your body clock, and what daygauge shows you.
Morning light helps your body clock, but UV needs care
How morning light, UV exposure and vitamin D relate to sleep, and what daygauge shows: time in daylight from Apple Health next to your sleep.
Wearables can show stress proxies. They cannot read your mind
How HRV, resting heart rate and sleep give recovery context, and why daygauge does not diagnose stress or burnout.
Ultra-processed foods: what they are and how to test your own habits
What ultra-processed foods are, and how to log a related habit in daygauge and see it next to your sleep and movement. No food tracking or guilt.
Glucose stability: what CGM shows and what daygauge does not
What glucose stability and CGM time in range mean, and what daygauge can and cannot show about them.
Microplastics are not part of the Life Index
What we know about microplastics and the body. daygauge does not measure microplastics.
Endocrine disruptors: what the research says and what an app cannot tell you
What endocrine disruptors are, what daygauge can and cannot show, and how to log related habits without hormone or fertility guesses.
Hair changes need a timeline, not a premature cause label
Hair shedding and hormone searches are common, and a timeline of sleep, stress and habits is more useful than guessing a cause. daygauge does not test hormones or diagnose.
Sauna is a useful experiment topic, not a universal prescription
How to treat sauna and heat exposure as a logged experiment and compare it with your own sleep and recovery, without longevity or treatment claims.
Alcohol is one of the clearest personal recovery experiments
How to compare alcohol logs with your sleep, HRV, resting heart rate and next-day movement in daygauge, without the lecture.
Air quality can explain why the same walk does not always feel the same
What air quality can and cannot tell you about sleep and outdoor activity, and how to compare a related habit with your own readings.
Bedroom CO2 is a possible sleep clue, but it takes a sensor to measure
What bedroom CO2 and ventilation can mean for sleep, and how to compare a ventilation habit with your own sleep and heart readings.
PFAS is a topic to understand, not a number an app can give you
How PFAS shows up in water, cookware and packaging, and how to log a related habit in daygauge without implying personal exposure levels.
The useful screen insight is timing, not blame
How late-evening screen habits can be compared with your sleep timing, without blame or diagnosis.
Fasting is about timing and fit, not willpower
How eating windows and late meals relate to sleep, and how to test a change of your own with a Quick Log habit. Not medical advice.
Protein and fibre help you feel full. Here is how to test it yourself
What protein and fibre do for fullness, and how to log a related habit in daygauge and see it next to your sleep and movement. No calorie counting.
Cold exposure works best as a logged experiment
How to treat cold showers and cold plunges as a logged experiment and compare them with your own sleep and heart readings, without treatment or longevity claims.
Cycle tracking is opt-in, private and free
How cycle tracking in daygauge sits next to your sleep, HRV, wrist temperature and resting heart rate, when you turn it on.
Travel breaks routines in ways your wearable rarely explains
How travel shows up in your sleep, movement, daylight and recovery readings in daygauge.
Home days and office days often look different in your data
How to compare home and office days in daygauge, using your places, movement, sleep and recovery readings.
Caffeine timing is an easy experiment to run on yourself
How to compare a caffeine cutoff with your sleep timing, sleep duration, HRV and resting heart rate in daygauge.
Supplement tracking should be simple and private
How to keep a simple private log of supplements such as creatine, omega-3, vitamin D and magnesium and compare it with your training and sleep.
Research context only. daygauge does not diagnose, treat, prevent or predict disease risk. Personal medical concerns belong with a qualified clinician.