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How to Read Your Oura Ring Data: A Fitness Pro's Guide to HRV, Deep Sleep, and Readiness

11 min read

Inspired by Bella Anya Kraft (@bellaanya) — an online fitness coach from Wisconsin (308K followers) who uses Oura Ring data daily with her clients. Her viral TikTok (495K+ views) walks through the three metrics she checks every morning, complete with real numbers from her own ring. This article expands on her insights with additional scientific context.

📹 Watch the original TikTok video →


You've got the ring on your finger. The app is installed. And now you're staring at a dashboard full of numbers, graphs, and color-coded bars wondering: what does any of this actually mean for me?

You're not alone. The Oura Ring tracks a staggering amount of biometric data — heart rate, body temperature, blood oxygen, movement, sleep stages — and presents it across multiple screens. For a new user, the sheer volume can feel more overwhelming than helpful.

Bella Anya Kraft, a fitness professional who regularly has her clients share their Oura Ring screenshots as part of their coaching, has a refreshingly simple approach: focus on three metrics. Every day. That's it.

Those three metrics are heart rate variability (HRV), deep sleep duration, and your Readiness Score. Together, they give you a surprisingly complete picture of how your body is recovering, adapting, and preparing for what's next.

Let's break down each one — what it measures, what the science says, and how to actually use it.

Heart Rate Variability: Your Body's Stress Report Card

What HRV Actually Measures

Heart rate variability is the variation in time between consecutive heartbeats. If your heart beats 60 times per minute, those beats aren't perfectly spaced one second apart — there are tiny fluctuations, sometimes 0.9 seconds between beats, sometimes 1.1 seconds. HRV captures that variation.

This might sound like a flaw, but it's actually a feature. Those fluctuations are controlled by your autonomic nervous system (ANS) — the branch of your nervous system that handles things you don't consciously control, like digestion, heart rate, and the fight-or-flight response.

Your ANS has two sides:

  • The sympathetic nervous system — your "gas pedal." It speeds things up when you need to respond to a threat or stressor.
  • The parasympathetic nervous system — your "brake pedal." It slows things down, promotes recovery, and helps you rest.

When both systems are functioning well and your body is recovered, there's a healthy push-and-pull between them, which creates more variability between heartbeats. When you're stressed, sick, sleep-deprived, or overtrained, the sympathetic side tends to dominate, and that variability drops.

As Bella puts it simply: HRV reflects "your body's ability to respond to stress." Higher generally means more resilient. Lower generally means your system is under load.

This isn't just fitness-influencer wisdom. A substantial body of research supports HRV as a reliable marker of autonomic nervous system function. Studies published in journals like Frontiers in Public Health and the European Heart Journal have consistently linked higher resting HRV with better cardiovascular health, improved stress resilience, and more effective recovery from physical exertion.

Why You Should Never Compare Your HRV to Someone Else's

Bella emphasizes a point that's crucial and often overlooked: HRV is deeply individual. Your baseline number depends on your age, sex, fitness level, genetics, and a dozen other factors. A 25-year-old endurance athlete might have a resting HRV of 80+. A healthy 55-year-old might sit around 25–35 and be doing perfectly fine.

Research confirms this. Population-level HRV norms vary so widely that comparing your number to a friend's — or to an influencer's — is essentially meaningless. What matters is your trend over time.

How to Actually Use Your HRV Data

Bella's approach is practical: she looks at her HRV across the week and identifies her personal range. From her own data, she knows that readings in the 45–65 range signal a good day. Readings in the single digits or teens tell her something is off — she's been sick, under-recovered, or made choices (like a late night out) that her body is still processing.

Here's how to build your own baseline:

  1. Wear the ring consistently for 2–3 weeks before drawing any conclusions. The Oura app needs data to establish your personal trends.
  2. Look at weekly averages, not single days. One low reading doesn't mean something is wrong. A sustained downward trend over several days might.
  3. Correlate dips with what you did. Poor sleep? Alcohol? A heavy training block? Illness? HRV drops after these are expected and normal — they show your body is working to recover.
  4. Use it directionally, not prescriptively. A low HRV day doesn't mean you can't train. It means you might want to check in with how you're feeling and adjust intensity accordingly.

The Oura Ring measures HRV during sleep (specifically during your most restful periods), which research suggests provides a more stable and reliable reading than daytime spot-checks.

Deep Sleep: Where the Real Recovery Happens

Why Deep Sleep Matters More Than Total Sleep

Sleep isn't one thing. Throughout the night, your body cycles through several stages: light sleep (N1 and N2), deep sleep (N3, also called slow-wave sleep), and REM sleep. Each serves different functions, but deep sleep is where the heavy-duty physical repair work happens.

During deep sleep:

  • Growth hormone release peaks. The pituitary gland secretes the majority of its daily growth hormone during slow-wave sleep, which is essential for muscle repair, tissue recovery, and cellular regeneration. This has been well-documented in endocrinology research, including studies published in The Journal of Clinical Endocrinology & Metabolism.
  • The immune system ramps up. Cytokine production — proteins that help fight infection and inflammation — increases during deep sleep.
  • The brain clears metabolic waste. The glymphatic system, which flushes out waste products from brain cells, is most active during deep sleep, according to research published in Science.

This is why Bella pays such close attention to deep sleep with her fitness clients. If you're training hard but not getting adequate deep sleep, you're essentially shortchanging the recovery process that makes training productive in the first place.

How Much Deep Sleep Do You Need?

This is where things get nuanced. Sleep research generally suggests that adults need roughly 1 to 2 hours of deep sleep per night, though this varies by age (deep sleep naturally decreases as you get older) and individual physiology.

Bella shares that she personally aims for at least 1.5 hours, ideally closer to 1 hour and 50 minutes to 2 hours, from a total of about 8 hours of sleep. From her work with female clients, she's observed that dipping below an hour of deep sleep tends to correlate with noticeable effects: slower recovery, increased fatigue, more cravings (especially for sugar), and a general feeling of being off-balance.

Her observations align with what we know about the relationship between sleep deprivation and appetite hormones. Research has shown that insufficient sleep — and particularly insufficient deep sleep — is associated with increased ghrelin (the hunger hormone) and decreased leptin (the satiety hormone), which can drive cravings and overeating. A landmark study in the Annals of Internal Medicine found that sleep restriction significantly altered the body's metabolic response to food.

Reading Your Deep Sleep Data in the Oura App

The Oura app shows your sleep stages as colored bars in the Sleep tab. Here's what to look for:

  • Check the absolute number, not just the color coding. The app's thresholds may not perfectly match your personal needs.
  • Track it over weeks. One night of low deep sleep after a late dinner or a stressful day is normal. A consistent pattern of low deep sleep is worth investigating.
  • Consider what might be suppressing it. Alcohol is one of the most potent deep sleep disruptors — even moderate consumption can significantly reduce slow-wave sleep, which multiple studies have confirmed. Late-night eating, screen exposure before bed, caffeine consumed too late in the day, and inconsistent sleep times can all play a role.
  • Don't obsess over it nightly. Paradoxically, anxiety about sleep quality ("orthosomnia") can itself disrupt sleep. Use the data as a gentle feedback loop, not a source of stress.

The Readiness Score: Your Daily Green Light

What Goes Into the Score

Oura's Readiness Score is a composite metric — it pulls together multiple data points from the previous night and recent days to generate a single number out of 100. According to Oura, the score factors in:

  • Resting heart rate and its trend
  • HRV and its trend
  • Body temperature deviation
  • Sleep quality and duration
  • Previous day's activity levels
  • Recovery index (how quickly your heart rate stabilized during sleep)

The result is a single number that attempts to answer a simple question: how ready is your body today?

Bella uses it as a training decision tool, and her thresholds are straightforward:

  • Above 70: Green light. Push hard, train with intensity, go after your goals.
  • Below 50: Yellow or red light. It might not be the best day for a grueling session. Consider lighter movement, mobility work, or rest.
  • In between: Use your judgment. Check in with how you actually feel.

The Science Behind Composite Readiness

The idea of combining multiple physiological signals into a readiness or recovery metric isn't unique to Oura — it's a concept that has roots in sports science. Professional athletic programs have long used combinations of HRV, resting heart rate, subjective wellness questionnaires, and training load data to make decisions about athlete readiness.

A 2019 review in Sports Medicine found that HRV-guided training — where athletes adjusted their training intensity based on daily HRV readings — produced equal or better outcomes compared to rigidly following a pre-planned program. The key insight: listening to your body's signals (with data to back them up) helps prevent the overtraining that derails progress.

Oura's Readiness Score essentially automates a version of this process for everyday users. It's not perfect — no algorithm can fully capture how you feel — but it provides a useful starting point.

How to Use Readiness Without Letting It Run Your Life

A few practical tips:

  • Don't skip every workout because of a low score. Sometimes a moderate session can actually improve how you feel. The score is input, not orders.
  • Look for patterns over rigidity. If your Readiness is consistently low, that's a signal worth investigating — are you sleeping enough? Training too much? Under chronic stress?
  • Use it alongside how you actually feel. Data and subjective experience should inform each other. If your score is 85 but you feel terrible, listen to your body. If your score is 55 but you feel energized, trust that too.

Putting It All Together: A Daily Check-In Routine

Based on Bella's approach, here's a simple morning routine for reading your Oura Ring data:

  1. Open the Oura app and check your Readiness Score first. This gives you the big picture.
  2. Look at your HRV. Is it within your normal range? Significantly above or below?
  3. Check your deep sleep. Did you get at least an hour? Closer to 1.5–2 hours?
  4. Make a decision about your day. High readiness + good HRV + solid deep sleep? Train hard. Low scores across the board? Prioritize recovery.

The entire process takes about 30 seconds. Over time, you'll start to internalize your patterns and won't even need to think about it — you'll glance at the dashboard and immediately know where you stand.

Key Takeaways

  • Focus on three metrics daily: HRV, deep sleep, and Readiness Score. Everything else is supplementary.
  • Never compare your HRV to someone else's. Track your own trends over weeks and months.
  • Aim for 1–2 hours of deep sleep per night. Consistently falling below an hour is worth investigating.
  • Use the Readiness Score as a guide, not a command. It's one input among many — including how you actually feel.
  • Give the ring time. The first 2–3 weeks are calibration. The real insights come after.

Go Deeper With Your Data

Your Oura Ring generates rich data every night — but seeing the full picture across weeks and months can be hard in the app alone.

Simple Wearable Report connects to your Oura Ring and generates free, lab-style health reports that surface your HRV trends, sleep patterns, and recovery data in a clean, shareable format. It's designed to be something you can actually bring to a doctor's appointment, share with a trainer like Bella, or just use to understand your own trends more clearly.

Free, GDPR-compliant, and takes about two minutes to set up.

See your trends → simplewearablereport.com


Watch Bella's full Oura Ring data guide: https://www.tiktok.com/@bellaanya/video/7592037417293597965


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