oztechmuse (2323576) writes "Samsung has just released an updated version of its health software for the Samsung Galaxy S5 that measures stress levels. Using the heart rate sensor on the back of the phone, the S5 will calculate a measure of stress from low to high. Although this may seem far-fetched to some, the phone is actually using a measure of the heart rate to calculate something called 'heart rate variability' or HRV. HRV has been shown to be related to a range of clinical conditions that include problems with the heart but also mental issues of stress and anxiety. Athletes have also used HRV as a measure of over-training and so use heart rate monitors to check if they need rest days. Samsung seems to be claiming the ground in terms of innovation in health-related sensor technology. In addition to the built-in pulse oximeter sensor used for the HRV measurements, Samsung phones now support direct connections to heart rate straps using the Ant+ protocol as well as through Bluetooth. Apple and others have a long way to go to catch up."