The CORE Body Temperature Monitoring sensor is similar to Heart Rate Monitor sensors in that it uses ANT+ and BLE and it paired to an athletes sport computer or watch and the data is only visible to them.
The CORE sensor is not a telemetry device. The CORE sensor is fastened securely to the heart rate monitor strap using the securing clips.
The current version 10.06.2021 UCI (Union Cycliste Internationa) Cycling Regulations states the following:
§ 4 Onboard technology
Devices which capture or transmit the following physiological data are authorised: heartrate, body temperature, sweat rate. The authorisation is, however, limited to transmission protocols which enable only the rider concerned to view the data during a competition.
The ITU (International Triathlon Union) does not limit the use of core body temperature monitoring sensors during competition.
Athletics and Running Races
The IAAF (International Association of Athletics Federations) World Athletics Technical Rules (1. November 2019) states:
6.4 For the purpose of this Rule, the following shall not be considered assistance, and are therefore allowed:
6.4.4 Heart rate or speed distance monitors or stride sensors or similar devices carried or worn personally by athletes during an event, provided that such device cannot be used to communicate with any other person.