Smartwatches and Fitness Tracker

Wearable Technologies: A focus on Smartwatches and Fitness Trackers

This short review focuses on one category of Wearable Technologies: Smartwatches and Fitness Trackers and their use of Core Body Temperature monitoring for a broad range of applications.


Wearable Technologies – A definition

The term “Wearable” or “Wearables” or even “Wearable Technologies” describe all various technologies that employ electronic devices that can be worn as accessories, integrated into clothing, or even implanted or tattooed in the user’s body or skins. [1,3]

The industry of Wearable Technologies kicked off in 2014 with the development of smartphones and low energy bluetooth that allowed those products to develop fast. The industry of wearable technologies comprises various product categories from E-textiles, hearables, extended & virtual reality (ER & VR), to smartwatches. The growth of wearable technologies industry accelerated in recent years despite the COVID-19 represented by the launch of the 7th generation of the Apple watch in 2021. [2]

Smartwatch fitness tracker
Example: SensArm, Waire Health‘s Technology to develop the most advanced medical grade wearable vital signs monitor with integrated Core Body Temperature sensing.

The rapid adoption of such technologies has placed wearable technology at the center of the Internet of things (IoT). Indeed, throughout the years, devices computing abilities, features and the sensors incorporating them have been multiplied driven by the advances in allied technologies such as wireless communication, computation and miniaturization.

and sensor technology thereby making smart devices central to diverse and disruptive applications, particularly related to monitoring, tracking and analytics. The emergence of wearables that contain multiple sensors has further augmented the capabilities of monitoring, sensing, tracking and data analytics, especially in the fields of Health & Wellness and Sport & Fitness.

The Evolution of Smartwatch and Fitness Trackers markets

This market is a booming consumer device market – initially driven by the activity market and nowadays dominated by smartwatches. Primarily a consumer device and B2C market driven by the largest payer – Apple, it now extended to fitness, wellness but also to health monitoring with companies offering technologies for Workplace Health and Safety.

Smartwatches and Fitness trackers allow to monitor real-time key physiological metrics.

The most widely monitored metrics are the following.

  • Step counting (activity characterization & metrics)
  • Geo-localization
  • Blood pressure and other cardiac metrics based on optical HR, HRV, spO2).
  • Temperature (peripheral, core body temperature) for fever detection and ovulation monitoring.

An example of successful Core Body Temperature sensor integration into a Smartwatch

Waire Health Integration
Example of successful OEM integration into Waire Health Technology.

greenTEG’s Core Body Temperature Monitor was successfully integrated into SensArm, Waire Health‘s Technology to develop the most advanced medical grade wearable vital signs monitor for non-invasive, continuous and remote patient monitoring.

Who uses Core Body Temperature Monitoring via Smartwatches or Fitness Trackers?

This short video relates well the advantages of Core Body Temperature monitoring for Individual Health Monitoring including Sleep or Circadian Cycle Tracking:

greenTEG offers the world’s first core body temperature sensor for continuous and non-invasive measurements on the wrist, upper-arm and chest body positions. greenTEG’s CALERA® technology has been developed and validated by more than 10 clinical trials showing for all position, clinical grade accuracy.


[1]Tiwari V.N., Bopardikar A.S., De A. (2022) Non-invasive Monitoring of Health Using Sensor-Rich Wearables and Smart Devices. In: Gargiulo G.D., Naik G.R. (eds) Wearable/Personal Monitoring Devices Present to Future. Springer, Singapore.

[2] IDTechX Webinar – 2021