greenteg CORE 2 Sensor – Core Body Temperature Measurement in Sports

Product Information

greenteg CORE 2 temperature sensor - core body temperature monitoring for sports

Product description

The CORE 2 temperature sensor is an innovative wearable device for the continuous monitoring of core body temperature and skin temperature during physical activity. It was specifically developed for endurance and performance athletes who want to optimize training control, pacing, and recovery using temperature-based data. The compact sensor measures thermal values in real time and transmits them via Bluetooth Low Energy or ANT+ to compatible sports watches, bike computers, or the CORE app. This makes it possible to track individual temperature trends and heat strain values at any time and integrate them into existing training analysis. The CORE 2 temperature sensor is non-invasive and uses a precise algorithm-based method supported by extensive validation studies.

By combining core body temperature, skin temperature, and the calculated heat strain value, athletes can better understand how strongly the body is being thermally stressed during training. This information supports the targeted adjustment of training intensity and cooling strategies, especially in hot environments or demanding race situations. The system is suitable for a wide range of sports, including cycling, running, triathlon, and winter sports.

Features

• Continuous temperature monitoring: Measures core body temperature and skin temperature in real time during exercise and recovery.
• Algorithm-based calculation: An AI-supported algorithm analyzes the body's heat transfer to estimate core temperature reliably.
• Heat Strain Index (HSI): Shows the body’s current thermal load based on multiple temperature values.
• Heat zone analysis: Automatically assigns four heat zones to help assess training intensity in warm conditions.
• Heat training load: Evaluates daily heat-related strain on a scale from 0 to 10 in order to track adaptation over time.
• Heat adaptation score: Reflects individual heat adaptation on a scale from 0 to 100% based on repeated training sessions.
• Easy integration: Compatible with leading training platforms and sports devices via Bluetooth Low Energy and ANT+.
• App support: Displays and analyzes measured values in the CORE app for Android and iOS.
• Lab-validated accuracy: Delivers results comparable to invasive reference measurements in scientific testing.

Benefits of the CORE 2 temperature sensor

• Accurate data collection: Continuous core body temperature monitoring supports reliable assessment of thermal strain during training.
• Scientifically validated method: Based on internal and external studies showing high accuracy compared with invasive reference methods.
• Broad device compatibility: Connects via Bluetooth Low Energy or ANT+ to compatible watches, bike computers, and training platforms.
• Improved training control: Helps adjust training intensity, cooling strategies, and recovery based on real-time data.
• Comfortable to wear: Lightweight and low-profile design that can be worn discreetly under sports clothing.
• Long battery life: Up to six days of active use or up to 30 days in standby mode, charged via magnetic USB-C cable.
• Water-resistant: IPX7-rated for use in wet conditions and during heavy perspiration.
• Sustainable packaging: Supplied in fully recyclable packaging made from environmentally friendly materials.

Scope of delivery

• 1 x CORE 2 temperature sensor for monitoring core body temperature and skin temperature
• 1 x CORE 2 clip for attaching the sensor to compatible chest straps
• 1 x magnetic USB-C charging cable for convenient charging
• 1 x product information and user manual with usage instructions
• 1 x environmentally friendly, fully recyclable packaging

Technical information

• Dimensions: Sensor without clip approx. 41.9 × 29.4 × 7.1 mm, with clip approx. 45.1 × 32.6 × 9.6 mm
• Color: white
• Weight: Approx. 8.6 g without mount, approx. 11.4 g including clip
• Power supply: Rechargeable battery with up to six days of operation and up to 30 days in power-saving mode
• Charging: Via the included magnetic USB-C cable
• Data transmission: Wireless connection via Bluetooth Low Energy or ANT+ in the 2.4 GHz range
• Protection rating: IPX7 certified, protected against sweat and splashing water, submersible up to 1.5 m
• Measurement accuracy: Average deviation between −0.01 °C and +0.23 °C according to validation tests
• Compatibility: Works with the CORE app (Android/iOS) and numerous devices from Garmin, Wahoo, Polar, and other Bluetooth- or ANT+-enabled brands

Application areas

• Monitoring core body temperature during endurance, running, triathlon, and cycling training
• Observing the body’s thermal response under training and race conditions
• Supporting cooling strategy planning and performance management
• Integration into professional training platforms for performance analysis

Additional notes

• The CORE 2 temperature sensor is intended for monitoring body-related temperature values and does not replace medical diagnosis or treatment.
• For reliable data transmission, the use of a compatible heart rate sensor is recommended, especially during intense exercise.
• Measurement results may vary slightly depending on environmental conditions, movement, and sensor position.
• For long-term use, regular cleaning of the sensor and chest strap clip is recommended.

Important note

This product does not replace medical treatment. If you have any questions about your personal well-being or health, please seek professional medical advice.

About greenteg

greenteg AG is a Swiss technology company based in Zurich. Since 2009, the company has been developing precise sensor solutions for heat flux and temperature measurement. With its calera® technology, greenteg offers OEM-ready solutions for sports, medtech, research, and occupational safety. The CORE sensor is the wearable sports application of this technology.

Further information

Core body temperature plays a crucial role in athletic performance. During intense physical activity, muscles produce heat, which can increase body temperature. To prevent overheating, the body redirects blood from the muscles to the skin, where sweat evaporation helps cool the body, although this may also reduce speed and performance. By monitoring core temperature, athletes can make more informed decisions about pacing and cooling in order to perform more effectively. Heat training can also help the body adapt to higher temperatures, which may improve performance. For example, one study showed that cyclists improved their time-trial speed by 8% after completing ten days of heat training.

The CORE sensor measures the transfer of heat energy between the body and the surrounding environment. An AI-supported algorithm is used to calculate core body temperature with high accuracy. The reliability of CORE data has been validated by comparison with internal body temperature data collected through more invasive methods. This enables precise monitoring of thermal status with a non-invasive, wearable device.

The scientific basis for the benefits of heat training is well documented. Heat training can improve the body’s ability to cool itself efficiently and perform under warm conditions. Reported physiological adaptations include increased blood plasma and hemoglobin volume, a higher sweat rate, and an earlier onset of sweating, all of which may support performance across a range of temperatures.

Further information on CORE accuracy can be found here: Scientific data validating CORE accuracy. Relevant research papers can be found here: Selected thermoregulation research papers.