A wearable is a trend line, not a coach and not a diagnosis. Heart rate, sleep staging, strain, maybe HRV. Useful when you look at weeks. Harmful when you grade last night and then cannot sleep. We cover the Oura Ring, WHOOP, Garmin, Fitbit, and older watches. Pick one ecosystem and stay.
How to use the number
Ask one question per week: did bedtime drift, did strain outrun sleep, is resting heart rate creeping up? Then change one thing. The device does not replace bloodwork. It does not replace sleep hygiene. Walker would rather you not weaponize the score. Johnson weaponizes everything; you do not have his staff.
Accuracy is “good enough” for HR, messy for sleep stages, optimistic for calories. Train by feel plus one metric, not by twelve dashboards.
FAQ
Ring, strap, or watch?
Ring for sleep and stealth. Strap for training strain. Watch if you already live on a wrist and want GPS. Function first.
Should I wear it 24/7?
Most of the time, yes, or the trends die. Take it off if the anxiety is worse than the insight.
Is WHOOP “better” than Oura?
Different jobs. WHOOP leans training. Oura leans sleep. Read the reviews, pick one, stop comparing forums.
Not a medical monitor. Chest pain and arrhythmias are an ER, not a recovery score.

