While measuring you heart rate when exercising gives you a certain level of insight into your performance, it doesn’t give you the complete picture. That’s because particularly in extreme heat, body temperature has a direct influence on both your vital signs and level of performance. To get around the possibility of misleading vital statistics, Munich-based startup Cosinuss created an in-ear wearable that not only measures your heart rate and its variability, but also your body temperature, sending all the data via Bluetooth to your phone or other devices in order to optimize your training and competitive performance.