Why Your Sleep Score Doesn't Tell the Whole Story

You check your Oura ring before you've had coffee this morning. Your HRV is down three points from last night. Your sleep score says 62. Neither number tells you why.

Your device monitors. It doesn't analyse. That's not a flaw, it's a limitation. This limitation sometimes becomes a source of anxiety on its own.

What HRV and sleep score are actually measuring

Heart rate variability (HRV) is the variation in time between each heartbeat. A higher HRV generally points to a nervous system that's recovering well. A lower one can mean stress, poor sleep, illness, or a hard training block. Sleep score is a composite metric, usually built from time asleep, time in each sleep stage, and how often you woke up.

Your device may show you the number of both, but they can't tell you why. Your Oura ring doesn't know whether last night's drop followed by a heavy training session, a stressful week at work, or the start of a flu. It just knows the number moved.

The other thing to watch out for is that different devices often don't measure the same way. Oura averages HRV across the whole night. Whoop measures it during your last stretch of deep sleep. Garmin folds it into a broader Training Readiness or Body Battery score. That's part of why your Oura and a friend's Whoop can disagree about what looks like a similar night, and part of why any single number, from any device, needs a person to read it in context rather than a notification to react to.

HRV specifically is a proxy for how the autonomic nervous system, the system managing stress response, heart rate, and hormone release, is functioning. A 2023 literature review in Frontiers in Neuroscience found HRV is tied to executive function, decision-making, and emotional regulation, and that unusually low HRV shows up across a wide range of conditions, from mild cognitive impairment and migraine to stress and anxiety. One low reading doesn't necessarily point to any of these reasons. It means the number reflects something real in the nervous system, and reading it correctly takes more than a glance at a graph.

The same review flags a technical catch worth knowing. A pattern called heart rate fragmentation, an erratic beat-to-beat rhythm, can make standard HRV readings look more dramatic than the underlying change in the nervous system actually is, particularly with age or around cardiovascular events. The raw number on your ring or your watch isn't always a clean read on what's happening in your body.

The gap between knowing and doing

Resmed's 2026 Global Sleep Survey, run with The Sleep Charity across 2,000 UK adults, found that 80% of us rank sleep as the most important thing we can do for long-term health. Only 55% actually do anything about it.

That's a 25-point gap between knowing and doing. The survey's own data points to why: stress and anxiety, not a lack of awareness, are what get in the way. People aren't ignoring the number. They're not sure what to do in response to it, and for some, the number itself becomes one more thing to worry about.

The same number means something different for everyone

A resting heart rate of 62 means something different depending on who's wearing it. For a marathon runner, it might be an unremarkable resting rate. For someone just starting an exercise, it might reflect early cardiovascular adaptation. For someone under sustained stress, it might sit alongside other signs worth paying attention to.

The number is identical. What it means depends entirely on the person, their history, and what else is going on in their body at the time. Your ring or watch doesn't hold that context. A conversation with a doctor might do.

What a consultation adds that an app can't

This is where a Body Brilliant consultation starts. A doctor asks what's actually going on for you, not what your app already told you. From there, the plan is built around your specific numbers, history, and goals, rather than a generic response to a metric.

Every plan is:

• Assessed by our clinical team

• Administered by registered nurses

• Delivered under the oversight of our medical team

• CQC regulated throughout

None of this replaces your ring or your watch. It gives the data you're already collecting a context and a plan.

What this isn't

A consultation isn't a diagnosis delivered on the spot, and it isn't a promise that any single treatment will change your HRV or sleep score. It's a clinical conversation that puts your numbers in context and builds a plan around what's actually happening for you, not around the number in isolation.

Next step

If a number on your tracker has been sitting with you without an explanation, that's worth a conversation, not another device or app. Book a consultation with our clinical team to talk through what your data actually means for you.

Sources

Arakaki, X., Arechavala, R. J., Choy, E. H., Bautista, J., Bliss, B., Molloy, C., Wu, D.-A., Shimojo, S., Jiang, Y., Kleinman, M. T., & Kloner, R. A. (2023). The connection between heart rate variability (HRV), neurological health, and cognition: A literature review. Frontiers in Neuroscience, 17, Article 1055445. https://doi.org/10.3389/fnins.2023.1055445

ResMed & The Sleep Charity. (2026). Global Sleep Survey 2026. https://sleepsurvey.resmed.com/