greenteg CORE Sensor - Body Core Temperature Monitoring

greenteg CORE Sensor – Precise Control of Core Body Temperature

The CORE Sensor by greenteg is an advanced wearable device for the continuous monitoring of core body temperature. It is designed for athletes who aim to optimize their performance through precise temperature management. This non-invasive tool allows users to monitor how body temperature affects performance in real time and adjust training or competition strategies accordingly. By analyzing core temperature, users can develop personalized cooling protocols to ensure optimal performance under varying environmental conditions.

Product Features

• Accurate real-time core temperature monitoring: Enables tracking of core body temperature to optimize performance and wellbeing.
• Measured parameters: Core temperature / skin temperature / heart rate (external) / accelerometer and heat flux (heat flux available upon request – contact us for details).
• AI-powered calera® sensor technology – validated in more than ten clinical studies.
• Compact and lightweight design: With dimensions of 50 × 40 × 8.35 mm and a weight of just 12 g, it is unobtrusive and comfortable for daily use.
• Bluetooth® BLE and ANT+ connectivity for seamless pairing with sports watches, bike computers, and smartphones.
• CORE App & Cloud platform for data analysis and trend tracking (iOS / Android).
• Waterproof and sweat-resistant: Rated IPX7 – waterproof up to 1.5 m, resistant to sweat, and easy to disinfect.
• Long battery life: Up to 6 days of continuous use and up to 6 weeks in standby mode.
• No calibration required: Ready to use straight out of the box.

Product Benefits

• Optimize performance through targeted temperature control and adaptation to different conditions.
• Supports heat training and competition preparation.
• Prevents overheating and reduces performance drop-offs.
• Data-driven analysis for sports science and coaching applications.
• Personalized cooling strategies for improved endurance and speed during competition.
• Safe, non-invasive use: Comfortable to wear without interference from thermal environmental factors.
• Waterproof and sweatproof: Meets IP68 standards, submersible up to 1.5 m.
• Extended battery life: Up to 6 days of uninterrupted measurement per charge.
• Deeper body insights: Understand your body’s temperature responses and their effects on performance.

Package Contents

• CORE Sensor
• Magnetic USB charging cable
• 6 medical-grade adhesive patches
• Clip for attachment to heart rate monitor strap
• Setup guide for the CORE iOS / Android app

Technical Specifications

• Size: 50 × 40 × 8.35 mm
• Weight: 12 g
• Accuracy: Medical-grade precision, based on ISO 80601-2-56#
• Non-invasive measurement
• Measured parameters: Core temperature, skin temperature, heart rate (external), acceleration, heat flux
• Stable accuracy independent of ambient thermal conditions
• Battery type: Rechargeable lithium-polymer battery
• Water resistance: Up to 1.5 m (IPX7)
• Connectivity: Bluetooth BLE, ANT+
• Battery life: Up to 6 days active / up to 6 weeks standby
• App support: iOS, Android
• Medical device: No
• The CORE Sensor is compatible with a wide range of sports technologies:
  • CORE iOS and Android App
  • watchOS
  • Wear OS
  • Garmin ConnectIQ watches and bike computers
  • Wahoo bike computers
  • COROS watches
  • Suunto watches
  • and more. (View compatible devices). Using CORE together with a heart rate monitor is recommended for maximum accuracy.

Important Information

The CORE Sensor is not a medical device and is not intended for diagnostic or therapeutic use. If you experience health issues, please consult a medical professional. Safety information regarding exposure to chemicals such as nickel and BPA is available at P65Warnings.ca.gov.

About greenteg

greenteg AG is a Swiss technology company based in Zurich, specializing in high-precision sensor solutions for heat flux and temperature measurement since 2009. With its calera® technology, greenteg provides OEM-ready solutions for sports, MedTech, research, and occupational safety applications. The CORE Sensor represents the wearable implementation of this technology for sports and performance monitoring.

More information

Core body temperature plays a crucial role in performance. During intense physical activity, muscles produce heat, which can lead to an increase in body temperature. To avoid overheating, the body moves blood from the muscles to the skin, which leads to cooling through evaporation of sweat, but can also affect speed and performance. By monitoring core temperature, strategic cooling and pacing decisions can be made to optimise performance. In addition, heat training can promote adaptation to higher body temperatures, which can improve performance. For example, one study showed that cyclists were able to increase their time trial speed by 8% after ten days of heat training.

The CORE sensor measures the transfer of thermal energy between the body and the environment and uses an AI-based algorithm to calculate core body temperature with high accuracy. The reliability of CORE data has been validated by comparison with internal body temperature data collected using more invasive methods. This enables accurate monitoring of body conditions with a non-invasive, wearable device.

The science behind the benefits of heat training is well documented. Heat training can increase the body's ability to cool itself and perform more efficiently in warm conditions. Observed physiological adaptations include increased blood plasma and haemoglobin, increased sweat rate and earlier onset of sweating, which improves performance across a range of temperature conditions.
For more information on Core accuracy, click here: Scientific data validating the accuracy of CORE. Information on relevant research can be found here: Selection of relevant Research.

Frequently Asked Questions (FAQ)

How does the CORE sensor measure core body temperature?

The CORE sensor uses calera® sensor technology: heat flux and skin temperature sensors capture thermal signals. A smart AI algorithm calculates the core body temperature in real time.

Is CORE a medical device?

No. CORE is not a medical device and is not intended for diagnosis or treatment. Please consult a healthcare professional if you have medical concerns.

Do I need to calibrate the device?

No. CORE is ready to use straight out of the box – no factory or on-body calibration required.

Where should I wear the CORE sensor?

The most accurate placement is on a heart rate chest strap close to the body. Alternatively, CORE can be worn directly on the skin using the included medical-grade adhesive patches.

How long does the battery last?

Up to 6 days of active use and up to 6 weeks in standby mode. The sensor charges via the included magnetic USB cable.

Is the sensor waterproof?

Yes. CORE is IPX7-rated and waterproof up to 1.5 m. Ensure secure attachment and skin contact when swimming.

Which devices is CORE compatible with?

CORE connects via Bluetooth BLE and ANT+ with the CORE App (iOS/Android), Garmin devices (Connect IQ), Wahoo, COROS, Suunto, and both Wear OS and watchOS.

Can CORE help with heat training?

Yes. Real-time core temperature data helps you manage intensity, cooling, and hydration – reducing the risk of overheating and improving training efficiency.

Does sweat affect the measurements?

The sensor is designed for athletic use. Stable skin contact and correct placement ensure accurate readings, even during intense activity.

What data is stored and how is it protected?

Data can be stored in the app and optionally in the CORE Cloud. You remain in full control of synchronization and deletion – see the manufacturer’s privacy policy for details.

Are the adhesive patches skin-friendly?

Yes. The included patches are skin-friendly. For sensitive skin, test on a small area first and change the placement regularly.

Can I use CORE without a heart rate strap?

Yes, with the included adhesive patches. For optimal data accuracy during workouts, wearing it on a chest strap is recommended.