Sleep Tracking
How HRV Actually Works
We unpack what HRV really is and how it actually works to demystify the data from Oura, Apple Watch, Fitbit, and Garmin....
December 17, 2025
Read more
All research articles
Here you can find all articles published by the Terra Research team. All articles consist of original findings.
Sleep Tracking
How Do People Really Use Wearables?
We analyzed 93 days of continuous sleep data across Oura, Fitbit, Apple Watch, and Garmin users to answer a simple quest...
December 9, 2025
Read more
Sleep Tracking
Benchmarking Wearable Sleep Data Reliability
We analyzed sleep data from over 5,000 real-world nights across Oura, Apple Watch, Fitbit, and Garmin users. Garmin deli...
November 28, 2025
Read more
Oura Ring Series
Is Consistency Actually More Important Than Intensity?
In this report, we reveal why high-step users averaging 11,500+ daily steps succeed: consistency. Their 36% activity var...
October 23, 2025
Read more
Oura Ring Series
Which activity metrics actually matter? 28,000+ days analysed
Smart rings track five different activity metrics, but they don't always align. Drawing on nearly 28,000 days of user da...
October 9, 2025
Read more
Oura Ring Series
Burn More Calories, Sleep Like a Log?
An analysis of 1,000+ Oura ring users examined the relationship between daily calorie expenditure and sleep metrics. Act...
October 2, 2025
Read more
Oura Ring Series
GAMM analysis – can complexity tell us anything we don’t already know?
Based on an analysis of nearly 90,000 nights, the connection between sleep duration and next-morning HRV is minimal for...
September 25, 2025
Read more
Oura Ring Series
Think a good HRV score follows a good night’s sleep? Think again!
Despite their perceived link, sleep and HRV are only weakly correlated. The analysis of nearly 90,000 nights showed that...
September 20, 2025
Read more
Oura Ring Series
Descriptive HRV using Z scores
Based on an analysis of nearly 100,000 HRV records, this report reveals that most daily HRV changes are small, but large...
September 19, 2025
Read more
Oura Ring Series
Why Mondays Might Be Your Healthiest Day: What 1,000+ Sleepers Taught Us About Recovery
At Terra, we recently ran an analysis on wearable data from over a thousand (Oura) users, focusing on two key metrics: s...
September 18, 2025
Read more
Subscribe to Terra Research
Get the latest reports and insights from Terra Research delivered to your inbox.
By continuing, I agree to the Privacy Policy and Terms of Service.
