You have probably heard about the Body Mass Index and that it is not a very good measurement of your physical health. Bioelectric Impedance Analysis (BIA) is much better, but until relatively recently equipment for it was only available in gyms and clinics. Today, smart wearables such as the Galaxy Watch4 and Galaxy Watch5 can measure BIA anytime, anywhere. But how accurate can these wrist-worn devices be? A joint research team from Louisiana State University, the Pennington Biomedical Research Center and the University of Hawaii Cancer Center conducted a study to find out.
The studio recruited 109 participants, of whom 75 completed the full protocol. The readings from a Galaxy Watch4 were compared to clinical measurements performed using dual-energy X-ray absorptiometry (DXA) scanning and duplicate laboratory-grade octapolar bioelectrical impedance analysis.
When the watch measures BIA, it reports several key statistics: fat-free mass, fat mass, skeletal muscle mass, basal metabolic rate, and total body water. The study found that having these metrics readily available helped improve people’s understanding of their behavior and how to improve it.
The BIA statistics reported by the Galaxy Watch
Ultimately, nearly 60% of users increased their physical activity. An additional randomized control trial was happy that smart wearables reduced sedentary time by an average of 68 minutes. A meta-analysis of the effects of such wearables also showed that users increased their daily steps by more than 2,500.
As for the accuracy of the measurements, the study showed that the key statistics reported by the Galaxy Watch4 had between 97% and 98% correlation with the results of the two reference methods. Here is the conclusion from the study:
After systematic correction, smart-watch BIA devices are capable of stable, reliable, and accurate body composition measurements, with precision comparable to, but lower than, laboratory measurements. These devices allow for measurement in environments not accessible to laboratory systems, such as homes, training centers and geographically remote locations.
Obesity has become a global problem and is considered a chronic disease that develops over time due to eating more and exercising less. About 60% of deaths from cardiovascular disease are due to obesity.
Here’s how to use a Galaxy Watch to perform a BIA check, it all takes about 15 seconds:
Samsung also offers several tips to improve accuracy:
- Measure at the same time of day
- Measure on an empty stomach
- Measure after going to the toilet
- Measure when you don’t have your period
- Measure before doing activities that cause your body temperature to rise, such as exercising, showering or going to the sauna
- Measure after removing metal objects from your body, such as necklaces
