Is an ECG from your smartwatch actually useful?
For detecting atrial fibrillation, a smartwatch ECG can be useful, especially as a complement to medical monitoring. For other heart conditions, the evidence is still too limited.
For atrial fibrillation (a heart rhythm disorder that can cause strokes), smartwatch ECGs have been well studied. Many studies combined show that such a watch correctly identifies the condition in 93% of cases and correctly does not raise the alarm in 94% of cases. That is impressive for a wristwatch.
In practice, performance varies considerably. A study of 201 patients tested five brands, including the Apple Watch 6, Samsung Galaxy Watch 3, and Fitbit Sense. Sensitivity ranged from 58% to 85%, and in 17 to 26% of measurements the software gave no verdict at all. When a doctor reviewed those borderline cases, 99% were still assessed correctly. Without medical follow-up, then, such a watch is a limited tool.
In older people who had previously had a stroke (average age 79), the Fitbit Charge 5 automatically missed as many as 66% of atrial fibrillation cases. But when it did raise the alarm, it was almost always right. A green notification is worth taking seriously; no notification is not the same as reassurance.
A major advantage of a smartwatch is continuous monitoring. Atrial fibrillation sometimes occurs in brief episodes that a one-off measurement at the GP's surgery would miss. The Apple Heart Study and Fitbit Heart Study show that smartwatches detect such episodes more often. For other heart problems, such as reduced blood supply to the heart muscle, the watch ECG does not yet work well enough.
Want to track your heart rate variability, a measure of recovery and stress, using a Samsung smartwatch? Do it at night. During the day, movement causes too many measurement errors. Night-time readings do match a standard measurement well. And remember: a smartwatch flags potential issues, but it does not replace a doctor or healthy habits.
Based on a wide range of studies, including large ones involving tens of thousands of people. The evidence that smartwatch ECGs can detect an irregular heart rhythm called atrial fibrillation is the strongest. For other uses, the evidence is thinner.
How reliable are the heart rate scores from your wearable?
A good wearable measures resting heart rate reliably, but HRV scores and readiness are less accurate than they appear. Use them as a signal over the longer term, not as a hard daily diagnosis.
Is a calcium score of my heart worth doing?
For people between 40 and 75 years old in a grey zone regarding statins, a calcium score is a well-supported tool for making a well-considered decision about medication together with your doctor.
Are calcium supplements bad for your heart?
Calcium supplements may be associated with an increased heart risk, but not all studies confirm this. It is best to get calcium from your diet, and discuss with your doctor whether a supplement is truly necessary for you.
Does climbing stairs actually do anything for my heart?
People who climb stairs regularly show a clearly lower risk of dying from heart disease in large studies. Even five minutes a day appears to be enough to improve your cardiometabolic profile.
Are erectile problems an early sign of heart disease?
Erectile problems caused by poor blood flow precede a heart attack or stroke by an average of 2 to 5 years. If you have this type of complaint, also have your cardiovascular risk checked by your doctor.
Is the Mediterranean diet really good for your heart, and why?
For people at increased heart risk, the Mediterranean diet is the best-supported dietary choice currently available. Both large studies in people and dozens of population studies confirm a lower risk of heart attack and stroke.