In recent years, patients often come to me with questions related to their smartwatch readings. Common questions include changes in heart rate, VO2max readings, or sleep scores. These changes are often asymptomatic, meaning that the patient does not notice any physical signs or changes, and it is only the smartwatch readings that has prompted them to seek medical advice.
Another related question that patients often ask is, how do smartwatch readings compare to traditional medical equipment? It’s important to understand that these measurements have long been measured with specialized equipment which undergo strict quality control and calibration. While smartwatches are becoming more sophisticated and their readings increasingly approximate professional standards, they still have limitations.
For instance, step counts from smartwatches can be a useful gauge of daily activity. However, measurements of oxygen saturation and heart rate, similar to those from finger probe monitors, can be affected by skin contact and movement. More complex metrics such as blood pressure, VO2 max, and lactate thresholds are derived from estimates based on physical activity and heart rate patterns rather than direct measurements. Sleep scores are also calculated from these indirect metrics. Despite these limitations, smartwatch technology is advancing rapidly. Some smartwatches are now FDA-approved for detecting and alerting for irregular heart rhythms such as atrial fibrillation, blurring the line between lifestyle and medical devices.
So, should you invest in a smartwatch? The answer depends on the individual. For some, these devices offer valuable health insights and encourage healthier habits. For others, they may cause unnecessary anxiety. Either way, smartwatches do not substitute health checks with your doctor.
Personally, I find my smartwatch useful for tracking my sleep and reminding me to meet my weekly cardio goals. On the other hand however, I’ve often been disappointed by a low sleep score despite feeling refreshed. Take smartwatch readings with a grain of salt and use them to enhance, rather than constrain your life. Remember, people managed perfectly well without smartwatches for centuries. If your device alerts you to sudden changes or anomalies, it is still best to discuss these with your doctor.
This article was contributed by Dr Penny Lee.
