Your watch grades your sleep every night. Here's how to read the report card and actually improve it.
Garmin's sleep score is a 0-100 rating that combines multiple aspects of your sleep into a single number. It's calculated from data collected by your watch's optical heart rate sensor and accelerometer throughout the night.
The score isn't just about hours in bed. Seven hours of high-quality sleep with solid deep sleep and REM stages will outscore nine hours of restless, fragmented sleep every time.
Total time asleep (not time in bed). Garmin detects sleep onset and wake time using movement and heart rate patterns. Target: 7-9 hours for most adults.
How restful your sleep was. This factors in how many times you woke up, movement during sleep, and overall restlessness. Fewer disruptions = higher quality score.
Based on HRV data during sleep. This measures how effectively your body recovered overnight. Strong parasympathetic activity during sleep pushes this score up.
The balance of light, deep, and REM sleep. Deep sleep handles physical recovery. REM handles cognitive recovery and memory. Both matter, and you need enough of each.
90-100 (Excellent) - Rare. Everything aligned. Long duration, minimal wake-ups, strong deep and REM stages, good HRV recovery.
70-89 (Good) - This is where you want to be most nights. Solid sleep across all components.
50-69 (Fair) - Adequate but not great. Something was off, whether it was duration, disruptions, or sleep stage balance. One fair night is fine. Multiple in a row is a signal.
Below 50 (Poor) - Significant sleep issues. Short duration, fragmented sleep, poor recovery. Training hard after a night like this is counterproductive.
The transitional stage. You cycle through light sleep multiple times per night. It's important but not where the magic happens. If your light sleep percentage is very high, it might mean you're not getting enough deep or REM sleep.
This is where physical recovery happens. Growth hormone is released, muscles repair, and the immune system strengthens. Athletes need adequate deep sleep to adapt to training. It's concentrated in the first half of the night, which is why early bedtimes matter.
Cognitive recovery, memory consolidation, and emotional processing happen during REM. It's concentrated in the second half of the night, which is why cutting sleep short in the morning robs you of REM time. Alcohol heavily suppresses REM sleep.
SmartMiles tracks your sleep trends and adjusts your training accordingly
Bad sleep night? We'll tell you to dial it back. Stacking great sleep? Time to push. Data-driven, every day.
Learn More at SmartMiles