Wellness calculators
Sleep, recovery and the daily habits that sit underneath every other metric.
Nothing published in this section yet
Why this section is still small
Sleep, recovery and daily habit load sit underneath every other metric on this site, but the published equations for quantifying them are much weaker than the ones behind BMI or energy expenditure. Sleep-cycle calculators are the clearest case. Most assume a fixed 90-minute cycle and 15 minutes to fall asleep, then print wake times to the minute, when real cycle length runs between roughly 70 and 120 minutes and drifts across the night. We could publish that tool tomorrow. We would have to cite an assumption rather than a study, so the section stays thin until the sourcing holds up.
Wellness guides
When a Health Number Warrants a Doctor's Visit
Calculators are screening prompts, not diagnoses. Here are the categories of result that deserve a professional opinion, and how to make that appointment useful.
Understanding Health Metrics: How to Read a Number Without Overreacting to It
Every health number carries a population of origin, an error range and a threshold drawn by committee. Here is how to read one without overreacting to it.
How to Build Habits That Survive Month Three
The 21-day figure is a myth with no study behind it. Here is what the research on automaticity, implementation intentions and friction actually supports.
NEAT: The Largest Movement Variable Nobody Tracks
Non-exercise activity thermogenesis varies by hundreds of calories a day between similar people, and it falls quietly when you diet. Here is what the data shows.
Stress, Cortisol and Weight: Untangling a Badly Oversold Story
Cortisol is not a fat-storage switch. Chronic stress does affect body weight, but through sleep, eating and movement rather than a direct hormonal route.
Sleep and Metabolism: What Short Sleep Does to Appetite and Training
Short sleep raises hunger, shifts what you lose on a diet from fat toward lean tissue, and blunts training quality. Here is what the controlled trials found.