"APP"-ropos?

A London woman desperate to get her lazy boyfriend to exercise has invented an iPhone application that measures how many calories you burn off having sex, The Sun reported Wednesday.

The download, called the Bedometer, analyzes the time and intensity of each sexual encounter—and you can post your results on Facebook. "The results have been amazing. My boyfriend can't get enough of it," Livvy Thompson, 25, said.

The gizmo is put on the bed and measures raunchy activity using the iPhone or iPod Touch's motion sensor before adding up the calories.

Administration worker Thompson, of Islington, North London, wanted to encourage lover Dan Dinapoli, 25, to tone up. "Our initial tests show that a vigorous workout for 15 minutes burns almost 200 calories each," she said.

The 99 cent invention follows the Passion application which analyzes a user's bed moves and gives advice on how to improve.

Meanwhile, the life-saving iResus has become one of the fastest-selling apps ever. It tells users how to save heart attack victims.