What a sleep score can and cannot explain
What an Underbark Sleep Score summarizes, why recorded and felt sleep can disagree, and where the score's interpretation should stop.
Learn how sleep, recovery, and health readings can add context.
These guides explain what your records can show, what gaps can mean, and where an honest interpretation should stop.
Start here
New to Underbark? Begin with the first-open guide, then explore sleep and recovery in more detail.
Sleep
Understand recorded sleep, gaps, and what a Sleep Score can summarize.
Recovery
Put daily recovery and heart-rate readings in the context of your own recent history.
What a recovery score can and cannot tell you
How a personal recovery score can add context without becoming a diagnosis or instruction to train.
Heart-rate variability, resting heart rate, and your personal baseline
Why heart-rate variability and resting heart rate are more useful as part of your own recent history than as isolated numbers or population targets.
What to expect when you first open Underbark
Why your first results depend on the history available for comparison, what an unavailable or calibrating result means, and why early results can change.
Why Underbark compares you with your own history instead of a population average
Why published ranges for heart-rate variability and resting heart rate describe few individuals well, what a personal comparison shows instead, and where it still falls short.
Training
Understand how current-day Activity Score differs from recovery context.
Why Activity Score and recovery can look different
Why today's Activity Score and recovery context can move differently, what each Underbark result summarizes, and where their meaning stops.
Apple Watch
Learn about Apple Watch sleep records and common reasons information can be missing or old.
Why is some of my Apple Watch sleep data missing?
Why an Apple Watch night may be partial, what missing sleep stages mean, and what you can check when Apple Health has less detail than expected.
Can Underbark work on Apple Watch without your iPhone nearby?
What remains available on Apple Watch without an iPhone nearby, what can become out of date, and how to check missing or older information.
Privacy
Use practical controls for Apple Health access, Underbark exports, and device changes.
Control Apple Health access and Underbark data
Practical steps for Apple Health permissions, missing information, exports, and changing or erasing an iPhone.
Your Underbark export and where it goes
An overview of Underbark exports and preparing for an iPhone change.