CORE Quick Start Guide

Everything you need to know to get started with your CORE device.

Let’s Get Started

01 What’s in the Box?

With each CORE device you will find the following contents. (Look under the black cardboard insert):

  • CORE sensor
  • Adhesive patches
  • Securing clips
  • Magnetic USB charging cable
  • Quick start guide
  • Product information sheet

02 Charging

Connect the charging cable to a USB power source (e.g. phone charger or computer, but not a power bank).

Leave it on charge until the LED stops blinking. Note that it may take up to 30min to start blinking in the initial charging phase, and then may take up to another 2 hours for a full charge.

A full battery charge will last five to six days.


03 Powering On

Disconnect the charging cable and shake the sensor until the green light starts blinking. This indicates that the device has begun to measure and that it’s ready to connect with your smartphone, smartwatch or sports computer.


04 Connecting with the App

The CORE App lets you:

  • Connect to CORE sensors
  • View your temperature data
  • Perform firmware updates
  • Pair to a heart rate monitor

  1. Download and install the iOS CORE App or Android CORE App on your mobile device.
  2. Start the CORE app and follow the instructions on the screen. Ensure Bluetooth is enabled on your mobile device.
  3. Make sure to update to the latest firmware on your new CORE sensor.


05 Pairing with a Heart Rate Monitor

Pairing with a HRM is critical for accurate data. The CORE sensor uses a complex algorithm to calculate core temperature. During sports, the lack of a heart rate signal will cause inaccurate data.

The HRM only needs to be paired once (the sensor will connect automatically after that).

Pairing is easy using the CORE iOS App or CORE Android App.


06 Pairing with 3rd Party Devices

Once paired and the data fields are set up, most sports devices automatically find and connect to the CORE sensor and record the core body temperature into the FIT file.

For a complete list of compatible devices and software, click ‘learn more.’


07 Wearing the CORE Device

For the most accurate measurements, position the sensor on the torso below the armpit using a heart rate monitor strap or the provided patches. Ensure consistent placement across sessions.

The CORE sensor can be worn elsewhere on the body such as on the arm or wrist; however measurement accuracy can be reduced.

When the sensor is mounted on a strap, remember to use one of the provided black plastic clips to hold it in place.


08 Device Maintenance

You can easily ensure you get a long life from your CORE device with these steps.

  • Rinse your CORE device with water and mild soap after each use.
  • The device can be disinfected with rubbing alcohol (ethanol or isopropanol).
  • Elevated temperatures (such as a sauna or hot automobile) will shorten battery life. Store CORE in a dry and cool location.
  • Regular charging of the sensor will prolong the battery live – the charge should ideally never drop below 10-20%.



Still having trouble? Check out the CORE FAQs and Troubleshooting resources here.


What Does CORE Show You?

CORE measures and records five important metrics. They are displayed live on your connected 3rd-party device, and summarized in the CORE mobile app.


Your Heat Strain Index can fall into 1 of 4 Heat Zones. The heat training zone (Zone 3) is the one that causes physiological adaptations that improve performance. Time spent in each zone is tracked on the CORE app.



Heat Strain describes the physiological processes that cool the body. The harder the body works to cool itself, the greater the strain, and the greater the impact on performance. CORE’s Heat Strain Index (HSI) quantifies this strain in real time using an algorithmic combination of core and skin temperatures.



Core body temperature is the temperature near internal organs in the torso. Core temp rises when we exercise, and if it rises too high, performance suffers. The CORE sensor continuously records your core temp. 



Skin temperature varies widely depending on environmental conditions. While skin temperature helps your body regulate core temperature, there is often little correlation between the two. It’s possible for your skin to be cool (and you will feel cold) while your core temperature is quite elevated. The CORE sensor continuously records your skin temperature.



Thermoregulation in Sports

Recording and Reviewing Data

The CORE sensor sends real-time data to paired devices and also saves up to a month of data internally. However, when the sensor fully runs out of battery, the recorded data is lost. 

Sports devices will display your real-time data and save it so it is available for later viewing and analysis. This is commonly saved in .fit file format which is convenient to share, view and analyze in sports software.

For the data stored internally, the CORE app can be used to read and synchronize with the CORE Cloud. This stores your historical data which you can view on the CORE App and CORE Cloud.



Training and Racing With Your CORE Sensor

When you get hot, your power output drops.

The more you know about your individual core body temperature behaviour, the better you can train and race. Performance can be improved by implementing strategies in 3 categories; Heat Training, Active Cooling, and Avoiding Overheating.

01 Heat Training

Introducing controlled and repeated increases in core body temperature is a highly effective training approach that conditions the body to operate more efficiently when it is hot. Heat training increases the blood volume and improves the physiological efficiency that enables athletes to increase power output and improve performance in both hot and cool conditions.

Heat training is similar to high intensity or altitude training in that it introduces a ‘stress’ and the body adapts to become better under these conditions.


02 Active Cooling

While racing, the lower the core body temperature, the more power is available. As the body heats, it diverts more blood away from the power-producing muscles to the skin (which the body cools through sweat evaporation). These cooling strategies provide a performance advantage by helping to keep the core body temperature lower.



Pre-cooling ahead of competition involves warming the muscles while keeping the core body temperature low. For example, a predetermined core temperature is reached through external cooling during a standard warm-up routine. Drinking ice slushies and wearing cooling vests are very popular strategies.


This can provide a cooling effect and relief. When ice melts on the skin, this helps evaporative cooling. However, consider that there are conflicting scientific viewpoints regarding the perceived positive effects of ice cooling against signals to the brain that may interrupt and slow natural cooling mechanisms of the body.


Pouring water over the head and body to externally cool the body and aid the evaporative cooling effect is highly effective, particularly in drier environments. Skin temperature values and the difference between skin temperature and core temperature, (which is calculated as the heat strain score) provide insights into the ability and efficiency of cooling.


This is the most effective way to lower core body temperature, even though it is rarely the preferred solution during races. During training and subsequently while racing, observing the real-time core body temperature enables a balance between pace/intensity and other cooling approaches. For example, pace could be reduced, but perhaps only slightly when combined with increased cooling.


Hydration directly impacts cooling. Hydration levels are not specifically identified by the CORE sensor though poor hydration leads to rising core body temperature. Losing more than 2% of body weight during training/competition is generally considered dehydration and harms performance. Also, remember that overhydration is dangerous.


Clothing impacts cooling. Both the clothing textiles themselves and the taking-off of layers play an important role. The discomfort of removing layers of clothing earlier than usual to lower the core body temperature can pay-off with longer sustained power.

03 Avoid Overheating

Racing and training in hot conditions increases the risk of heat-related injury and illnesses and threatens athletes who are unprepared or who overexert themselves.

It is encouraged to identify a core body temperature limit that you should not exceed. This temperature limit is well below dangerous levels and is intended as a preventative threshold. The intention is that if this limit is reached, you can still take steps to cool down while remaining safe and competitive.

The CORE sensor provides real-time core body temperature data so you can monitor your threshold safely and cool accordingly.


Cooler is Faster