June 12, 2021
Smartwatch Heart Rate and SpO2: What They Can Do
Updated September 2026: in 2021, during the COVID-19 pandemic, I explained why I was planning to buy a smartwatch to track heart rate and blood oxygen. I have rewritten it with a clearer view of what these features can and cannot do.
I had wanted a health wearable for a long time. During the pandemic, heart rate and blood oxygen tracking seemed like good reasons to buy one. At the time I wrote that heart rate monitoring was accurate enough to be worth having, and that blood oxygen readings could help people notice problems early. Looking back, the first point has held up better than the second.
How accurate are smartwatch heart rate readings?
For resting and everyday heart rate, reasonably good on major brands, though readings can lag during intense exercise. Some watches can also flag an irregular rhythm and take an ECG reading, which is useful as a prompt to see a doctor, not as a diagnosis.
Can a watch measure blood oxygen reliably?
Less reliably. Wrist readings are affected by fit, movement, skin and temperature. Most smartwatch blood oxygen features are sold for general wellness, not as medical devices. If you need to monitor oxygen for a health reason, a fingertip pulse oximeter, used as your doctor advises, is the better tool.
What else are wearables good for?
- Activity tracking: steps and exercise minutes encourage regular movement.
- Sleep patterns: useful for trends, less so for exact numbers.
- Fall detection and emergency calls: valuable for older users on some models.
- Notifications: fewer reasons to pick up the phone.
What should you check before buying?
Compatibility with your phone, battery life, which health features are enabled in India, and how the company handles your health data. Some features available abroad are switched off in certain countries.
Is a wearable worth it?
For fitness and everyday awareness, often yes. For medical decisions, rely on a doctor and proper devices. The watch is a nudge, not a clinic.
Did I buy one in the end?
The original post set out my reasons for buying. If you are weighing the same choice, try a watch in a shop for comfort and check the return policy, since fit affects both comfort and sensor accuracy.