Smart watches and fitness trackers have become increasingly popular in recent years. Apart from basic time display, they generally feature a myriad of functions such as heart rate and step count measurement, exercise tracking, health reminders, and instant messaging, making them daily essentials for health-conscious consumers. Based on the test conducted by International Consumer Research and Testing (ICRT) on smart watches and fitness trackers of various specifications and designs, the Consumer Council published the test results of 44 models available in Hong Kong. It was revealed that 3 models might count minor hand movements as steps, leading to step count deviations of up to 59% to 74%. The heart rate measurement performance also varied, with 2 models showing deviations of over 11% in most activities and even over 21% during cycling. The Council reminds consumers that the health and fitness data collected by smart watches or fitness trackers are estimates only and not necessarily accurate, thus they are suitable only for reference but not for medical use. Manufacturers should improve product design and quality to enhance accuracy, so that the data can serve as more valuable reference.
The test was coordinated by ICRT, with models mainly purchased in Europe, including 44 models available locally in Hong Kong. 38 models were smart watches, generally higher in price, ranging from HK$199 to HK$9,799. The variation in price was mainly due to brand, features, design, and materials. The remaining 6 models were fitness trackers, priced from HK$139 to HK$498. The test was conducted by a European laboratory, with 3 assessors wearing a sample of each model during various activities, including resting, low-intensity walking, high-intensity running and cycling. The recorded data were then compared against those obtained from precision instruments used simultaneously. Test items included fitness and health data, smart features, battery performance, ease of use, mobile applications, versatility, and build quality. Due to differences in design and features, the evaluation weightings of smart watches and fitness trackers also differed and the performances should not be directly compared.
Deviations in Step Count of 3 Models Exceeded 59%
Many consumers wear smart watches or fitness trackers mainly to check the step count for daily activities, travelled distance, and heart rate, etc. as reference for daily exercise. All models have built-in 3-axis accelerometers and optical heart rate sensors to detect movements and changes in blood flow respectively, collecting wrist movement and heart rate data to estimate the step count and maximum and resting heart rates.
The test found that most models performed well in estimating walking and running steps, with deviations not exceeding 7%. Among them, 25 smart watch models had deviations of no more than 3%, and were lower especially during running. However, some models showed larger deviations in estimating steps simulating daily life, with 3 smart watch models of the same brand showing significant deviations of 59% to 74%.
In the distance estimation test, assessors ran 2km respectively on an open route and a convoluted route with GPS signal partially blocked, and walked 900m in an open area. For the 33 models with built-in GPS sensors, this function was activated during the test. Results showed that the estimated distance of most smart watch models deviated by no more than 4.3% on average, showing outstanding performance. In contrast, 2 smart watch models not equipped with GPS had average deviations in estimated distance of 34.3% and 18.7% respectively, performing significantly worse. Among fitness trackers, 1 model had a deviation of 19% in estimated distance, thus was only rated 2.5 points.
2 Models Showed Heart Rate Deviations over 21% During Cycling
All models had heart rate measurement functions, but performance varied, with scores ranging from 2 to 5 points. Half of the smart watch models performed well with heart rate data deviating by no more than 7.5% for various activities. However, 2 smart watch models had deviations of over 11% for the measured heart rate in most activities and even more than 21% during cycling, affecting the overall heart rate measurement performance, thus received only 2 points. Another fitness tracker model was also rated 2 points as its measured heart rate deviated by over 11% for most activities. 41 models had blood oxygen level measurement function, but the performance varied considerably, with scores ranging from 1 to 5 points. 9 smart watch models had outstanding performance with data deviations of no more than 1.12%, while 2 smart watch models had higher deviations, receiving only 1.5 and 1 point respectively.
23 Smart Watch Models Had Voice Call Function
Besides monitoring fitness data, smart watches and fitness trackers also allow users to connect to their smartphones for instant messaging, phone calls, controlling music playback and photography. When receiving instant messages or other notifications, all models provided rather clear vibration alerts and could display notifications/texts for phone calls and instant messages, while only 23 smart watch models had built-in microphones and speakers for hands-free calls. To use voice assistants for weather or route enquiries, a built-in microphone is also required. Hence, models without built-in microphones could not perform voice commands, resulting in lower scores for smart features.
Battery Life Ranged from 1.5 Days to over 20.8 Days
For long-term outdoor use, battery life is crucial. All models had built-in rechargeable batteries which took 1 to 2.9 hours to fully charge from empty. When fully charged, usage time varied significantly, ranging from 1.5 days to over 20.8 days. 5 smart watch models and 1 fitness tracker model could be used continuously for nearly 3 weeks after a full charge, with 2 models taking only 1.8 hours to fully charge, outperforming other models. In contrast, the battery life of 3 smart watch models only lasted around 1.5 to 2.2 days, requiring charging every other day for 1.8 to 2.4 hours to fully charge, showing poorer performance.
Furthermore, 1 smart watch model’s screen cracked after being dropped 5 times from 0.8m onto a ceramic tiled floor, which affected its score. Consumers should consider the following recommendations when purchasing and using smart watches or fitness trackers:
- Carefully compare specifications and performance of different models before purchasing, and choose the most suitable one based on personal needs. For example, if hands-free calls and voice assistant functions are needed, choose models with built-in microphones and speakers;
- Wear the device on the wrist as instructed, not too loosely or too tightly, so as to avoid affecting the accuracy of the optical heart rate sensor;
- As the fitness data from smart watches or fitness trackers are estimates and not necessarily accurate, they are suitable only for reference and not for medical use;
- Regularly update firmware and change passwords to enhance network security and privacy protection.
Download the article (Chinese only): https://ccchoice.org/583-wearables
Consumer Council reserves all its right (including copyright) in respect of CHOICE magazine and Online CHOICE.