Issue #024 Review

The Lab: CORE Sensor – Core body temperature as a new performance criterion?

The CORE sensor elegantly measures the body’s core temperature, but for what purpose? And do you really need it? We thoroughly tested the sensor from Switzerland, priced at just under € 300. Find out here if regulating body temperature is effective and whether this monitoring solution is a must-have for you.

CORE Sensor | 14 g | € 298.95 | Manufacturer’s website

The Swiss-made CORE sensor is designed by greenTEG, specialists in temperature measurement. CORE has a clear objective: to provide athletes with reliable data that was previously only achievable through a lot of time and effort. Their focus lies on temperature management, which includes preventing overheating, avoiding overload, and enabling targeted heat training. But how does the sensor perform in our test, and how reliable is the data it provides? And ultimately, what is the point of it all anyway?

The CORE Sensor measures core body temperature, but what is its purpose?

Our body is efficient, but not as much as we would like it to be. We generate thermal energy (aka heat) during endurance sports, alongside the desired kinetic energy. This becomes particularly relevant in activities like cycling, where we experience prolonged exertion and limited cooling. When your body temperature rises, it can have a negative impact on your performance, at least in the immediate term. Understanding your own temperature is important, but you may wonder about the practical implications and whether you can actually influence it.

Is that all?
The compact sensor weighs only 14 g but comes with everything you need. The package includes an adhesive pad, a clip for the chest strap, and a magnetic charging adapter.

The answer to that question is both yes and no. While you may not have much control over your body temperature in extreme situations, such as having a body temperature of 39°C in a 40°C environment in the middle of nowhere, heat management actually begins much earlier. The best and most important strategy is to adjust your pacing accordingly. When your body temperature rises, it’s necessary to reduce speed and power to prevent overheating. Active cooling with the help of water is also effective. Wetting your jersey or hair can bring your temperature down to a healthier level. Precooling is another strategy used by highly ambitious athletes to enhance short-term performance. As hobby bikers, we may just need to reduce our effort slightly before the next climb to manage our body temperature effectively.

The 14 g lightweight CORE sensor is easily clipped onto the chest strap and secured with the safety clip, and goes unnoticed when worn.

Heat acclimatisation is also an important aspect, as better adaptation to warm temperatures can be achieved not only on hot days but also by wearing slightly more clothing. Finally, the CORE sensor allows data enthusiasts to track their own temperature in real time and over the long term. This can contribute to optimising recovery and sleep, as well as early detection of diseases, among other significant factors.

Medical grade accuracy and real-time data – What data does the CORE Sensor actually measure?

So the sensor has a lot of potential, but how does the small CORE sensor actually work? It measures the skin temperature and the transfer of thermal energy to and from the body. With the use of advanced algorithms, the sensor then calculates the core body temperature. For optimal results, the sensor is ideally paired with a heart rate sensor. It can be connected via ANT+ and Bluetooth, allowing for seamless integration with mobile phones, bike computers, and sports watches. The sensor is worn directly on the body, either attached to a chest strap or stuck to the chest using an adhesive pad. When worn, the sensor is virtually unnoticeable due to its small size and weight of just 14 grams.

Using the mobile app, users can view real-time and historical data of core body temperature and skin temperature, displayed as Heat Strain Score and Heat Load. Integration with popular bike computers such as the Garmin Edge series is also possible without any issues. An app is available in the Connect IQ Store, which allows the temperature to be displayed as a data field. All the collected data can be conveniently recorded and analysed using established training platforms.

Runs like clockwork
The CORE app for Garmin is available in the Connect IQ Store and functions flawlessly. Other manufacturers could learn a thing or two from their seamless performance.

CORE Sensor – The performance sensor of the future?

In our test, the CORE sensor performed exceptionally well. It seamlessly integrated with existing bike computers and sports watches without any issues. The app and the sensor are perfectly synchronised and thoughtfully designed. Overall, the CORE sensor sets a great example for other well-known manufacturers. In practical use, the sensor provides reliable and trustworthy data. While CORE provide some reference values, it’s important to note that these values can vary based on individual training conditions and personal differences. It may take some time to develop a thorough understanding and effectively use the data provided by the sensor.

All day everyday
With the help of an adhesive pad, the CORE Sensor can be comfortably worn all day long to monitor your body temperature.

With the body temperature sensor, CORE provide an easy-to-use and sophisticated solution for tracking your own temperature. The sensor’s impeccable craftsmanship ensures reliable data transmission to any device, offering valuable insights into your performance metrics unlike many other sensors. Given the increasing interest in temperature management and its significant relevance, the sensor holds great potential for the future. However, the relatively high but justifiable price tag of just under € 300 may be a slight deterrent.


  • simple, comfortable and uncomplicated to use
  • sophisticated system


  • at a price point of just under € 300 it primarily appeals to highly ambitious athletes

Tester: Calvin
Test duration: 4 months
Price: € 298.95
Weight 14 g
Manufacturer’s website:
Intended use: Gravel, Road, MTB

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Words & Photos: Calvin Zajac