If you just got a new wearable and are feeling overwhelmed by the data … or if you’ve had one for years and are still not sure that you’re extracting the maximum value … you’re in the right place!  Wearable health devices like WHOOP, Oura Ring, and Apple Watch provide a wealth of data—but how do you know which metrics actually matter? If you’re not sure what to look at, the sheer number of stats can be overwhelming. In this post, I’ll break down the most important metrics to track, why trends matter more than individual readings, and how to use this data to improve your health.

Which device is best?  WHOOP vs. Oura vs. Apple Watch vs. Garmin

By far the most common question I get asked, is “Megan, why in the world do you wear WHOOP and Oura?”  What can I say … I love metrics. As a Harvard economics graduate, previous investment banker and management consultant, and math nerd to my core, the more numbers the better.  And for me, WHOOP and Oura serve different purposes.  Overall, I prefer Oura for more “soft” metrics (like menstrual cycle tracking, temperature fluctuations, and even sleep), whereas I prefer WHOOP for more “intense” metrics (like strain score).  Oura is generally telling me “do less” (in fact, I have far more days with a low activity score on Oura because of inadequate rest than I do because of inadequate movement) and WHOOP is generally telling me “do more,” and I like the balance.

If you (like a normal human!) just want to wear one, though, here’s what I would recommend:

• Oura: If you’re looking to get more familiar with your menstrual cycle, or if you know you need to improve your sleep, stress management, and recovery, Oura is my #1 recommendation. Here’s a discount!
• WHOOP: If you would describe yourself as an athlete and are primarily interested in improving athletic performance, WHOOP is my #1 recommendation. Here’s a discount!
• Garmin: If you’re a runner looking to track runs, choose Garmin (will I overwhelm you if I tell you I also wear a Garmin Forerunner 55 on runs?!). If you’re looking for more robust statistics outside of runs, though, WHOOP or Oura are far better.
• Apple Watch: If you want to be able to take calls, get news, receive texts, and more from your device, Apple Watch is the clear winner. While I’ve tried it twice, I returned my Apple Watch both times, because for me, not having access to all of that is a gift.  The metrics are not quite as detailed as WHOOP or Oura, but passable if you’re looking for the basics.

What Do I Track?  The Most Important Wearable Metrics

Now that you have your device, let’s figure out what to track.  While wearables track dozens of data points, I recommend focusing on these four: Resting Heart Rate (RHR), Heart Rate Variability (HRV), Readiness Score, and Sleep Score.  Personally, I write down each of these 4 numbers (from Oura and from WHOOP) in my PEPPER Planner each morning.  Writing them down helps me focus on what’s important, and while I scroll through other metrics, I focus on these.  At the end of each day, I copy that day’s numbers into the next day’s page on my PEPPER Planner, and then when I write the new day’s numbers in the morning, I write a (+) or a (-) to indicate the trends.  If I am going in the right direction on all 4 metrics on any given day, I know what I did the day before was really helpful, and vice versa.

While there are many additional features, these four provide deep insight into recovery, fitness, and overall well-being. Let’s break down each metric, what it tells you, and how to improve it.

Resting Heart Rate (RHR)

• What It Is: Your heart rate when you are at complete rest, typically measured during sleep.
• Why It Matters: RHR is one of the simplest but most powerful indicators of overall fitness and recovery. A lower RHR generally indicates better cardiovascular fitness and recovery. If your RHR is suddenly elevated, it may signal stress, overtraining, or illness.
• What’s a good RHR?

• • Normal range: 50-70 bpm (varies by person)
  • Athletes: As low as 40 bpm
• How to improve it: Prioritizing aerobic fitness, improving stress management, increasing hydration, limiting or avoiding late-night alcohol and caffeine, and optimizing sleep quality.
• What does a high RHR mean? Could indicate overtraining, stress, dehydration, or illness.

• The science: A 2025 study in Progress in Cardiovascular Diseases analyzed data from 692,217 adults from Asia and Europe and found that RHR was an independent risk factor for all-cause mortality. In fact, it was an even better predictor for all-cause mortality than hypertension in those aged 20-50!

Heart Rate Variability (HRV)

• What It Is: The variation in time between heartbeats. Unlike RHR, a higher HRV is generally better and indicates greater adaptability to stress. This one is counterintuitive, because we tend to think the heart should operate like a metronome.  On the contrary, when there is more variability between beats, your heart is more relaxed and more resilient.
• Why It Matters: HRV is a marker of nervous system balance. The autonomic nervous system is divided into parasympathetic (“rest and digest”) and sympathetic (“fight or flight”), and when we spend more time in “fight or flight,” our HRV is lower. Low HRV can indicate overtraining, stress, poor recovery, or inadequate sleep.

• What’s a good HRV?  The current body of research suggests that HRV is individual, and that comparison between individuals is not useful.  Some people “naturally” have a higher HRV, and some “naturally” have a lower HRV.  Average HRV also varies widely by age and fitness level (e.g., 20-40ms is common for sedentary individuals, while 80-100ms is common for elite athletes).  That said, I have watched my own data every single day for well over 5 years, and I’ve gotten my HRV from single digits or teens to (sometimes) over 100, which would be impossible for those who suggest it is genetic.  I have also helped hundreds of clients monitor their wearable data, and I can say with certainty that those under higher stress (or, even better said, those who perceive their lives as stressful) tend to have lower HRVs, whereas those who cope with stress well have higher HRVs.  I believe research will emerge on this, and I would like to contribute to the research one day.  For now, it’s best to focus on your own trends rather than having a target of a specific number.
• How to improve it:
  • Breathing exercises like 4-7-8 breathing or box breathing (see my favorite breathing exercises here!)
  • Meditation (see the benefits here!)
  • Journaling, time in nature, yoga and any other stress management tool, including taking mental breaks during the day
  • Increasing fitness level
  • Sleep optimization: Consistent bedtime, avoiding alcohol, minimizing blue light, caffeine cut-offs, wind down routines, optimal sleep environments, and more
  • Nutrition and hydration: being well-nourished and well-hydrated has a direct impact on HRV
  • CBD: I have seen enormous differences in my own HRV when using CBD.  I have done numerous experiments over long periods of time, and the correlation is undeniable.  I prefer Pure Spectrum.
• Why readings may be different across devices: Comparison is tricky, because each device measures HRV at different times of the night, which can lead to discrepancies. WHOOP calculates HRV using deep sleep and last-stage readings, whereas Oura takes an average across the entire night.  For this reason, my WHOOP almost always reads higher in HRV.
• The science: While overtraining, alcohol, and poor nutrition get the bulk of the attention for lowering HRV, a 2019 study in Frontiers of Physiology confirmed that high mental workload significantly alters HRV, something that I see very clearly after days when I have 12 back-to-back client appointments with detailed lab reviews and long protocol write ups after each session!

Readiness Score

• What It Is: A composite score combining HRV, RHR, sleep, and recovery metrics to assess overall readiness for physical exertion. Each device has its own proprietary algorithm for readiness.
• Why It Matters: This score gives you an overall sense of how much you can take on in the day, which can help you determine whether you should push hard in training or focus on recovery.

• How to interpret:
  • High score (85+): You’re well-recovered and ready for performance.
  • Middle score (50-85): Listen to your body and make your own judgment call.
  • Low score (<50): You may need extra rest and recovery.
• How to improve it: Prioritize sleep, nutrition, stress management, and recovery techniques (e.g., sauna, cold therapy).  Reduce alcohol and late-night meals, stay hydrated, and avoid excessive caffeine.  Listen to your body and don’t ignore true fatigue, but also continue to prioritize your fitness.  So basically, everything you’ve ever learned from The Lyons’ Share!  It’s important to remember, though, that we don’t have to do everything; every step we take in the right direction can support higher readiness levels over time.

Sleep Score

• What It Is: A measure of sleep quality based on total sleep, sleep efficiency, and sleep stages (REM, deep, light sleep).
• Why It Matters: Poor sleep affects everything from cognitive function to immune health and metabolism.
• Is it accurate?: Most wearables break sleep into deep, light, and REM sleep. While exact algorithms are proprietary, studies suggest they are ~70-85% accurate compared to lab-based polysomnography. A 2022 study found that Oura ,WHOOP, Garmin, and Apple Watch sleep tracking were all 86-89% accurate compared to polysomnography.

• How to interpret:
  • Deep sleep (aim for about ~10-25% of total sleep, or at least 60 minutes): Important for physical recovery.
  • REM sleep (aim for about ~20-30% of total sleep, or at least 90 minutes): Crucial for cognitive function. Improve it with consistent sleep and wake times
  • Light sleep: Makes up the majority of sleep and is still beneficial
• How to improve sleep scores:
  • Establish a consistent wind-down and sleep routine, including a scheduled bedtime
  • Minimize blue light exposure before bed
  • Avoid alcohol and heavy meals close to bedtime, and have a caffeine cut-off
  • Use magnesium supplementation if necessary (learn more here)
  • The #1 correlation I’ve seen is allowing the brain time to unwind and release ruminating thoughts before bed.  I guide clients through tools like the post-it note brain-dump and the next day check-in in order to release these thoughts.

Additional Wearable Metrics Worth Tracking

• Temperature Fluctuations: Some devices, like Oura, track temperature trends. This can be useful for:

• • Cycle Tracking: Changes in body temperature can predict ovulation.
  • Illness Detection: Sudden spikes can indicate sickness.
  • Recovery Monitoring: A dip in temperature may correlate with overtraining or inflammation.

• Respiratory Rate: Measured during sleep, an increase in respiratory rate can signal illness or high stress.

• • Normal range: 12-20 breaths per minute, generally lower for athletes
  • Spikes in breathing rate may indicate illness, stress, or overtraining.

• Steps, Strain, and Activity Metrics: While steps and strain help quantify activity, they should be used in conjunction with subjective measures of effort. WHOOP’s strain score, for example, is based on cardiovascular load, while Apple Watch focuses on movement through the day and Oura primarily relies on steps but often misses activities like Pilates.
• Stress Monitors: Many devices include stress-tracking features based on heart rate fluctuations. While they provide general trends, self-awareness of stressors is still key.

• • WHOOP and Garmin have stress scores, but HRV is a more reliable long-term measure of stress resilience.
  • Oura offers “Restorative Time,” which tracks relaxation periods throughout the day.

• Journals and Tags: WHOOP and Oura allow users to tag behaviors (e.g., alcohol, late meals, meditation) and analyze how these impact key metrics. Tracking these patterns over time can reveal insights such as:
  • Alcohol significantly elevating RHR and decreasing deep sleep
  • Meditation and breathing exercises improve HRV
  • Late meals disrupting sleep score
  • High stress plummeting Readiness score

Final Thoughts: Listen to Your Body First

Technology is a great tool, and I personally continue to learn SO much from my wearables, but your own self-awareness should always take priority. If a device tells you to push hard, but you feel exhausted, honor your body’s signals. Use wearables as guides—not absolutes—in your health journey.

Want a discount on one of these products?

I have discounts for you for the two I wear – Oura and WHOOP.  After reading this, which do you think is better for you – WHOOP vs. Oura?

• Oura discount
• WHOOP discount

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️ Want to hear about this topic in audio format? → Check out the podcast episode here!