Smartwatches and fitness trackers have become increasingly popular, with many people relying on them to monitor their health and fitness. According to a recent review, these devices have a low accuracy in measuring heart rate, about 3%, and provide similar estimates of cardiorespiratory fitness, known as VO2 max.
The review also found that the accuracy of the calorie burn data is much lower than previously thought, with an error rate of between 15% and 21%. This means that people who rely on these devices to monitor their calorie burn should treat these numbers with caution.
The review also showed that sleep tracking via these devices may be inaccurate, with the error rate in estimating sleep duration and efficiency exceeding 10%, while the error rate in measuring sleep onset time reaches 180% when compared to specialized measurement methods.
Overall, these devices provide general guidance on health and fitness, but they are not a substitute for accurate medical advice and measurements. Therefore, they are best used as aids, taking into account the limitations of accuracy in the data they provide.
