Tinder users with an Apple Watch can soon zero in on their perfect match "hands-free". A new version of the popular dating app is built around the smartwatch's heartbeat monitor that automatically suggests a match depending on the heart rate.

The new app removes the need to swipe left or right and instead gauges the user's reaction by measuring his or her heartbeat.

Texas-based T3 showcased the features of the new app, dubbed "Hands-Free Tinder", in a YouTube video.

"All you have to do is look at the person on the screen. We monitor if your heart rate goes up, or if it goes down, to find the perfect match," the video says.

If the heart rate quickens, it's a match. If not, it's a pass.

The thinking behind this is backed up by science. Studies have shown that the heart rate of someone standing next to an attractive person increases.

The new app comes amid rumours of slackening demand for the Apple Watch.

Reports suggest online sales of the device have slumped 90% since the opening week, citing figures from Slice Intelligence.

Fortune recently conducted a poll of analysts that estimated around 4.5 million units of the smartwatch were sold in its first nine weeks of release.

Initial reviews for the Apple Watch were generally positive, but highlighted issues of performance and pricing.

Developers say the new Tinder app is coming to the App Store "soon".