Microwave sensor detects changes in heart rate

Current medical techniques for monitoring heart rate and other vital signs use electrodes attached to the body, but these are impractical to use on patients that move around.

Plasma physicist Atsushi Mase, a scientist at Kyushu University in Japan, and colleague Daisuke Nagae have developed a new monitoring technique that uses microwaves to resolve the problem.

The system uses very weak microwaves to irradiate – and scatter off – the human body. A microwave sensor then monitors the reflected waves, which change in phase in response to motions of the body, including the regular displacement of the chest during breathing or, the slight movement of the chest caused by the beating heart.

’The skin surface moves slightly, synchronising to respiration and heartbeat,’ said Mase.

Using signal processing algorithms and techniques to filter out the effects of random body motions, Mase and Nagae were able to detect changes in heart rate in near real time.

’We plan to apply the system to various conditions, including for clinical use – such as for the overnight monitoring of vital human signs – and as a daily health monitor, including detecting signs of sleepiness in drivers and preventing stress-related illnesses,’ added Mase.