Hot couple alert!

Kourtney Kardashian and her piece of A, male model Younes Bendjima, got hot and sweaty with a mid-day workout at Runyon Canyon in West Hollywood, hiking in the hot Los Angeles sun -- HOT being the operative word here ...

Keep in mind, peeps, Kourtney is a mother of three and 38 years old and Benjima is a young 24!!!! Just a year older than Kourt's other paramour, Justin Bieber! She likes 'em young!

And we can see why ... I mean, KK's baby daddy Scott Disick has some serious swag, but he doesn't have those abs!!!