Sleep is more than hours in bed. The new Sleep system starts with a score, then shows the signals behind it—heart rate, HRV, oxygen, breathing, temperature and timing—in the context of your own nights.
Open the report in the morning and Gyroscope explains what supported your recovery, what pulled it down, and which change is worth watching next. The number is the beginning of the story, not the verdict.
The score, and the night behind it
The 0–100 Sleep Score combines sleep duration, resting heart rate and HRV, each compared with your personal baseline. The full report can then add whatever your connected device records: bedtime and wake time, stages, oxygen, breathing rate and wrist temperature.
- A personalized score rather than a generic target
- A plain-language explanation for every night
- Detailed signals when you want to look closer
- Trends that separate one noisy night from a pattern
Caffeine has a longer tail than it feels like
A late coffee can still be active at bedtime even when you no longer feel the lift. Clearance varies considerably between people, which is why Gyroscope treats caffeine timing as personal context rather than a universal cutoff.
A small controlled sleep study found that caffeine taken even six hours before bed reduced measured sleep. The practical experiment is not to chase a perfect cutoff: move your last coffee earlier for a week, then compare your own sleep timing and recovery with the week before.
What the signals are actually for
Duration and regularity
Hours are still the foundation, but a single long night cannot summarize a schedule. The report keeps bedtime, wake time and duration together so you can see whether the whole week is steady. In a large observational UK Biobank study, sleep regularity predicted mortality risk more strongly than duration in that cohort. That does not prove causation; it does explain why consistency deserves its own trend.
Heart rate and HRV
Resting heart rate and HRV add recovery context after training, travel, stress, illness or a disrupted night. HRV is especially individual and differs by device and measurement method, so Gyroscope compares it with your own history instead of turning one reading into a universal grade.
Oxygen and breathing
Oxygen and breathing can show a repeated overnight pattern that duration misses. Consumer wearables cannot diagnose sleep apnea, and fit, movement, skin temperature and device accuracy can all affect a reading. Repeated drops—especially alongside gasping, heavy snoring, morning headaches or daytime sleepiness—are a reason to discuss the pattern with a clinician and seek appropriate testing.
Temperature and Time to First REM
Wrist temperature is not core body temperature, and wearable-estimated REM is not a laboratory measurement. Both are most useful as personal trends. A repeated shift from your normal temperature or from the usual timing of your first REM period can add context when other recovery signals move at the same time.
Your baseline changes the meaning
A resting heart rate of 55 bpm can be ordinary for one person and unusual for another. The same is true of HRV, bedtime, temperature and sleep duration. Gyroscope learns from your own nights so the report can distinguish “outside a population range” from “different for you.”
Sleep Battery keeps a rolling view of the last seven nights. Trends zoom out further, and the Weekly Review places sleep beside training, food, mood, travel and phone time. That hierarchy keeps one rough night from becoming the whole story.
Works with the wearable you already use
Apple Watch, Oura, Whoop, Garmin and Fitbit can feed the Sleep system. Apple Health is the primary source on iPhone, with direct connections available for supported services. The exact signals in a report depend on what your device records and exports.
Consumer wearables are not laboratory sleep studies. A 2025 meta-analysis found meaningful differences between wrist-worn trackers and polysomnography across several measurements, while noting their usefulness for following broader patterns. Consistent measurement matters more than over-reading one decimal place.
How to use it tonight
Update to the latest version of Gyroscope, connect the wearable you already use, and wear it to sleep. In the morning, start with the written explanation. After a week, open Trends and change one thing—a steadier wake time, an earlier last coffee, or a longer sleep window—so the next report has a clear question to answer.