Fitness monitor employs Nordic Bluetooth low energy technology

US start-up Hothead Technologies has specified Nordic Semiconductor’s nRF8001 Connectivity chip to provide Bluetooth low energy wireless comms in the world’s first fitness monitor to track body temperature in addition to conventional movement (time, speed and distance) and heart rate.

Various studies have shown that hyperthermia (body temperature greatly above normal = 37.5°C or over, as opposed to hypothermia which is body temperature greatly below normal = less than 35.0°C) can adversely affect both physical performance and reduce the benefits of exercise.

The Spree Fitness Monitor is the world’s first product to recognise this fact and, in conjunction with a free Spree app running on any Bluetooth v4.0 (which includes Bluetooth low energy as a hallmark feature) enabled smartphone or tablet, enables users to monitor their optimal temperature-movement-heart rate workout zone in real time.

In operation, all measurement technologies are integrated into a small performance optimisation device (POD) that fits securely into a water-resistant silicone elastic headband that the end user wears (and indeed additionally benefits from functioning) like a traditional sweatband.

All three sets of biometric information (body temperature, movement and heart rate) are then obtained from the forehead via a thermistor (an electronics device whose resistance precisely varies in response to thermal change) for temperature, a ‘photoplethysmograph’ for heart rate (an optical blood volume measurement technology employed in most emergency room pulse oximeters) and a triple-axis accelerometer for motion.

This, claims Hothead Technology, makes the Spree the most advanced personal fitness monitor in the world and far more accurate than existing wrist- or foot-worn devices, without the discomfort (especially for women) of heart-rate chest straps.

“Body temperature is a critical physical training and performance component, yet no other company or fitness monitor in the market today is doing temperature,” comments Steve Swaim, director of operations at Hothead Technologies.

“Yet overheating not only reduces the benefits of a workout and destroys peak endurance performance, but can also put the body in serious harm’s way: you are actually physiologically doing harm to your body when working out too hot.”

Swaim continues: “In addition, temperature gives the most accurate calorie burn rate it is possible to obtain and by including temperature with motion and heart rate, it is now possible (using our app) to visually see and continuously remain within the most optimal training or performance zone.”

“In addition to monitoring temperature, one of most interesting aspects of this application is the way in which it converges the ability to measure several separate fitness parameters into a single device,” comments Geir Langeland, Nordic Semiconductor’s director of sales and marketing. “I welcome such developments as they help make setting up and using the devices easier for end users, and that can only be a good thing.”