Monitoring performance, health and training intensity is much easier nowadays thanks to certain wearables. This is done, for example, via the measurement of heart rate, heart rate variability, speed, sleep quality and so on. Various wearables such as the Google Pixel Watch 3 measure body temperature via an infrared sensor. Other devices use direct contact-based measurements, such as the Fitbit Sense 2, which has a electrodermal activity sensor that measures skin temperature by monitoring the activity of sweat glands. Core 2 has a new sensor that focuses on measuring temperature in a slightly different and non-invasive way.
According to Core's blog, the 45.1 x 32.6 x 9.6 millimeter device will be 48% smaller and 30% lighter than its predecessor. The device still measures body temperature via a sensor based on the Seebeck effect, i.e, it measures thermal energy transfer between the body and the environment. In other words, the sensor detects the heat moving into and out of the body. An AI-powered algorithm then uses the data obtained "to calculate core body temperature with medical-grade accuracy".
Such a device can be useful for providing real-time data via the corresponding app during training in order to keep your core temperature within your optimal "heat training zone", to avoid overheating via certain cooling strategies and to inform you when to reduce power/pace. Users can also see how well their body is adapting to the outside temperature.
As for the differences between Core 1 and Core 2, the manufacturer states that "Core 2 is smaller, lighter, smarter and future innovation ready" and comes with a redesigned mounting system for easier removal/charging and a new LED battery status indicator.
Core 2 is expected to be available for sale in March 2025 for a price of $359.20. Shipping will be free for buyers in the US, UK, Canada, Mexico and Europe.