How accurate are Galaxy Watch Ultra and 7 for HR tracking

TL;DR

The Galaxy Watch Ultra and Galaxy Watch 7 both track heart rate quite well compared with an ECG chest strap, showing high correlation around 0.97. Some dips at low heart rates appear and sleep stage results vary, with Ultra generally aligning better on sleep stages than the 7. This is an initial test with more results coming later.

Transcript

the Galaxy watch Ultra and Galaxy watch 7 have a new sensor that Samsung claims has improved performance but is that actually true today we'll find out by systematically testing the heart rate tracking performance sleep stage tracking and GPS tracking and we'll also take a quick look at some other features like blood pressure FTP and body compositi... Read More

Key Insights

• The two Galaxy watches show strong heart rate tracking against an ECG reference with a correlation near perfect in some sections.
• The 7 and Ultra both align closely with the reference during spinning and cycling, though lower heart rate dips can be less accurately captured.
• Sleep stage data reveal good deep Sleep agreement for both devices, but REM and wake timing show more variability.
• Ultra demonstrates better REM and wake time alignment in the first night of data, compared to the 7.
• Between sessions, some tests show the 7 misses dips while the Ultra tracks them more consistently.
• The initial test uses a different testing day for inside cycling to compare performance against a chest strap.
• The watches are placed in a broader comparison against other devices to gauge relative performance in the market.
• This is described as an initial test with a full review to follow in a week or two.
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Questions & Answers

Q: How accurate are the Galaxy Watch Ultra and Watch 7 for heart rate tracking compared to an ECG chest strap?

Both watches show very good agreement with the ECG reference, with correlation values around 0.97 in the morning testing. For most segments, the data points cluster near the reference line, indicating high accuracy at higher heart rates. Some deviations occur at lower heart rates, but overall accuracy is strong for initial testing.

Q: What did the initial indoor cycling tests reveal about heart rate tracking?

In cycling tests, both watches generally agree well with the reference device, with similar performance between Ultra and 7. The Red and Blue curves indicate close tracking, though occasional dips at low heart rate ranges are not captured perfectly. The overall pattern suggests reliable HR tracking during cycling intervals.

Q: How does sleep stage tracking compare between Galaxy Watch Ultra and Watch 7?

Sleep data show deep sleep agreement is solid for both watches, with Ultra sometimes closer to the ECG device on deep sleep. REM and wake time comparisons are more variable, but the Ultra tends to align better on wake timing and RAM sleep than the 7 in the first night tested.

Q: Which watch performed better in sleep stage validation on the first night?

The Ultra generally demonstrates stronger RAM sleep agreement and better overall sleep stage alignment for the first night, with deep sleep similarity similar to the 7. REM and wake time have some misclassifications for both, but Ultra shows fewer discrepancies in RAM sleep compared with the 7.

Q: Were there any issues noted with low heart rate tracking during testing?

Yes, there were occasional deviations in the lower heart rate range where the devices did not fully capture dips. These occur in some spinning intervals and highlight that while overall HR tracking is strong, subtle dips can be missed in certain scenarios.

Q: How did the watches compare to other devices in correlation plots?

In broader comparisons, the Galaxy Watch Ultra and Watch 7 sit among higher performing devices with correlations in the top tier, suggesting competitive performance relative to other popular wearables tested in the same context.

Q: What is the scope of this video in terms of results and follow ups?

This video is described as an initial test with results shown as they are gathered. The creator plans additional cycling, weightlifting, and sleep analyses later, with a full review to follow in a week or two to confirm findings across more data sets and sessions.

Q: Are there any cautions about interpreting the sleep stage data from these watches?

Yes, sleep stage data show variability, especially for REM and wake detection, and the analysis cautions that more data is needed to draw definitive conclusions. The first night provides initial insights but not a comprehensive verdict on long term sleep tracking accuracy.

Summary & Key Takeaways

• The first night shows strong heart rate tracking with high correlation to the reference device, especially at higher intensities.

• Sleep stage comparison reveals deep sleep alignment is decent for both watches, but REM and wake detection vary more, with Ultra performing better overall.

• Overall initial results indicate the Ultra and 7 offer competitive HR tracking, with Ultra showing some sleep data advantages and the need for more data across activities.