What Theia tracks in Recovery
Recovery is a quick read on how rested your body is after a night's sleep. It comes from the heart signals your body gives off overnight, while you're lying still, and not moving or reacting to the day. A well-recovered night usually means your nervous system had a chance to settle and reset. When you're run down, whether from short sleep, a stressful stretch, a hard workout, or a cold coming on, that often shows up in these signals before you feel it yourself.
Theia's Recovery tile and graph are built on a single overnight measurement: Heart Rate Variability (HRV), which reflects how balanced your nervous system was while you slept. Your Resting Heart Rate (RHR) shows up on the same report as a separate, related metric that adds helpful context.
Both mean the most when you follow them over time against your own baseline.
Heart Rate Variability, the Recovery Signal
Your heart doesn't tick like a clock. Even when your pulse feels steady, the gap between one beat and the next keeps changing by small amounts, and that changing gap is your HRV, measured in milliseconds. Those shifts come from your autonomic nervous system, which has two sides: the Sympathetic nervous system, otherwise known as "fight or flight", and the Parasympathetic nervous system, otherwise known as "rest and digest." The Sympathetic system speeds up heart rate to prepare the body for handling stress, while the Parasympathetic system slows down heart rate and calms the body to help recovery. When the Parasympathetic system is in charge, HRV varies more and runs higher, whereas HRV tends to flatten out when you are stressed, under-recovered, or getting sick. More variability than your baseline is a good sign.
HRV is very personal. What counts as normal for one person can be a long way from normal for another, and age, fitness, and genetics all play a part. HRV also declines with age: a healthy person in their 20s often run close to double the overnight HRV of an equally healthy person in their 50s, and both are exactly where they should be. Because the raw number says so little on its own, Theia always reads your HRV against your own baseline (when available) rather than anyone else's.
Resting Heart Rate, a Companion Metric
Resting Heart Rate isn't part of the Recovery tile or the overnight graph, but Theia shows it within the report because it pars naturally with HRV. It's the number of beats per minute your heart settles into when you're fully at rest, measured overnight. A lower resting heart rate usually point to a well-rested, efficient heart. When it sits higher than your usual, your body may still be catching up, after a late night, a hard session, a few drinks, a stressful day, or an illness on the way.
The two signals tend to move in opposite directions. A good night usually shows higher HRV and a lower resting heart rate. An off night often shows the reverse, with HRV down and resting heart rate up. When HRV dips and resting heart rate climbs on the same night, that agreement is a stronger signal than either reading on its own.
Why Recovery Matters
Recovery says something about your metabolic health, not just how tired you feel. The nervous-system balance behind HRV is closely tied to how your body handles glucose.
Autonomic balance and insulin. Lower HRV show up repeatedly in people with metabolic syndrome and insulin resistance, the cluster of raised blood glucose and blood pressure that sits behind much of metabolic disease. A nervous system stuck in high gear and a body that struggles with glucose often go together.
Resting heart rate and diabetes risk. A higher resting heart rate lines up with higher long-term risk. Pooling many cohort studies, one analysis found that each extra 10 beats per minute at rest came with roughly a 20% higher chance of developing type 2 diabetes.
One connected system. Sleep, stress, movement, and glucose all run through the same autonomic wiring. A rough recovery night often sits next to a hard glucose day, so reading recovery alongside your sleep, activity, and glucose usually tells you more than a single view.
Reading Your Numbers
Because these signals are so personal, the goal is to compare yourself to yourself.
Your baseline. Theia learns your normal range over time. Until it has enough nights to do that well, you'll see a Building Baseline status. Theia requires 28 nights of overnight HRV data before your personal status band appears.
One off night is just noise. A single low or high HRV night rarely means much on its own. A late dinner, a glass of wine, a stressful evening, or tough workout can all nudge it. The direction over days and weeks is what to look for.
How Theia Show Your Recovery
Your Recovery view leads with HRV, then shows resting heart rate as its own metric.
Last night shows your most recent overnight HRV in milliseconds, with the date it was just measured. Early on, a Building baseline badge tracks how many of the 28 nights you've reached.
HRV Overnight plots your HRV across the window you're viewing. Below it sit three figures: 7-Day Avg, your recent average; Period Avg, the average across the selected window; and Trend, which shows whether your recent HRV is running up or down.
Resting Heart Rate compares last night against your recent baseline, so you can see at a glance whether you're above or below usual.
Switch between the 7D / 14D / 30D views or open the calendar to change the window. Manage shows your data source and last sync, and How Does This Work? opens a short in-app explainer.
Accuracy & Limits
Data comes from your wearable. HRV and resting heart rate are measured overnight by your connected device. Theia gathers them in one place for you and your care team.
Devices don't measure the same way. Wearables read HRV from different spots on the body, at different pints in the night, using different math. Your Theia number, pulled from your connected source such as Apple Health, may not match what another device or app shows, and that's normal. The absolute values vary, but the trends usually move together, and it's your own trend that carries the meaning.
Insight, not diagnosis. Recovery is here to help you understand how your body is coping and to share what you notice with your care team. It isn't a medical diagnosis. If a lasting change in your resting heart rate or HRV worries you, check in with your provider.
This article is for general and is not medical advice. Recovery signals vary widely from person to person, and your provider is your best partner for deciding what's right for you.
Need Help?
Our team is always glad to assist if you have any questions about your account.
Our support team can be reached via [email protected] or you may send us a message via the Help button in the Theia app.