Oura shows you a lot of numbers and almost no plain-English definitions. This glossary fixes that: every metric your ring reports, what it actually measures, and the one thing to remember about each. No medical degree required.
The tiny variation in time between heartbeats, measured overnight in milliseconds (Oura uses rMSSD). Higher generally means your nervous system is well-recovered; lower often follows stress, alcohol, illness or a hard workout. The number is meaningless in isolation — what matters is today versus your rolling average, not versus anyone else.
Your lowest heart rate during the night, in beats per minute. A stable, low RHR is a sign of good recovery and cardiovascular fitness. An overnight RHR several beats above your normal is one of the earliest signals of a late meal, alcohol, stress, or oncoming illness.
A 0–100 blend of your sleep, recovery (HRV and RHR), body temperature and recent activity. It’s a convenient summary, not a verdict — the same 74 can come from very different causes. Read it against your own baseline and reduce it to one decision: push, proceed, or ease off.
A 0–100 summary of the night, built from how long you slept, how much deep and REM you got, how efficiently you slept, how soon you fell asleep, and how settled the night was. Like readiness, it’s a roll-up — the components tell the real story.
Not your absolute temperature, but how far your skin temperature drifted from your personal baseline, in fractions of a degree. A sustained rise often precedes illness or marks the luteal phase of a menstrual cycle; alcohol and a hot room nudge it too. Trend matters more than any single night.
The estimated percentage of oxygen saturation in your blood overnight. Most healthy people sit in the high 90s. Oura reports an average and a variation measure; frequent dips can hint at breathing disruption, but a consumer ring is a screening signal, not a diagnosis.
How long it took you to fall asleep after going to bed. Very short latency (under a few minutes) can paradoxically signal you’re sleep-deprived; very long latency points to a too-early bedtime, stress, or stimulants. A healthy range is roughly 10–20 minutes.
The share of time in bed that you actually spent asleep, as a percentage. Above ~85% is generally considered good. Low efficiency means lots of awake time between lights-out and getting up — even if total sleep looks fine.
The stages of the night. Deep sleep does the physical repair; REM consolidates memory and mood; light sleep is the connective tissue between them. Healthy proportions vary by age and person, so chase your own typical mix rather than a textbook ideal.
Your average breaths per minute overnight, usually steady to a fraction of a breath. A sudden, sustained rise — like temperature — can be an early sign your body is fighting something.
An estimate of the maximum oxygen your body can use during hard exercise — the single best lab-style measure of cardiovascular fitness. It’s only meaningful against reference values for your age and sex; a 42 can be average or excellent depending on who you are.
Vitra takes every one of these and does the part Oura leaves out: it reads each number against your own personal baseline and turns it into one plain-English sentence, so you never leave a screen wondering whether a value is good or bad for you.
Local AI on your Mac or PC. One-time purchase, 7-day trial, no subscription.
Download Vitra →