Samsung confirms an upgrade to body-composition analysis in the Galaxy Watch4 series
The Galaxy Watch4 series has now been formally introduced as the successors to both the Galaxy Watch3 and Watch Active2 lines. They look similar, with the same new round AMOLED displays, although the upgrades to the latter is made with the OEM's new Armor Aluminum, whereas those of the former are made of stainless steel.
Internally, however, they both rock the same new "powerful" Samsung platform for wearables, not to mention an updated array of health- and fitness-related sensors. They support their predecessor's blood pressure, ECG and blood-oxygen (SpO2) metrics (now approved in more countries than before), yet have been extended to use-cases such as continuous SpO2 measurements during sleep.
However, the most advanced new upgrade here is to the Galaxy Watch4 series' new ability to assess a user's body composition. This is done through the technique of bioelectric impedance analysis (BIA), which, as with clinical-grade equipment, requires a lot of individual electrodes to divine metrics such as muscle mass based on the detection of water molecules throughout the body.
Samsung claims to have gotten around this problem through the integration of a 16-circuit system within each Galaxy Watch4 unit. They 'fire' at a rate of 2,400 times every 15 seconds in order to gather the necessary data on values such as body fat and basal metabolic rate, so long as the user 'completes' these circuits by touching the wearable's back and power buttons, and have the ultra-thin layer of chromium silicon carbon nitride placed on the back-plate of each watch for this purpose in contact with their skin.
Samsung asserts that measuring and tracking these variables of body-composition are vital to understanding the user's health and fitness over time. The OEM has also claims that its super-compact new system to do so has been tested and validated to the point that it equals the performance of benchmark DXA hardware.
These new features are controlled by Wear OS as promised, and are rated to keep going for up to 40 hours per charge in the new wearables. The new Galaxy Watch4 and 4 Classic SKUs start at US$249 and $349 respectively, and have Bluetooth-only and LTE-enabled options, and will be available from August 27, 2021.