Thanks to sprawl, the average Angeleno spends about a sixth of their day on their ass in traffic (often more). No wonder this state decided Restless Leg Syndrome was an actual ailment... If you live in LA you better be sure to find a regular source of exercise. Luckily, there are options depending on mood and location:
Runyon Canyon is the hotspot. If you're interested in really feeling your walk and not coming home to find you still need to stand up and move about for another hour or two I suggest going here. Now there are a number of different routes you can manage here. There's the easy easy, for beginners. Just walk up the long path and turn around... then come back down. Too easy. Try the regular, walking down the path to your right, turn left and follow the dusty trail up the side of a mountain and up the stairs. That guy can be fun. And you can always mix it up at the turn around. But my personal favorite is the hard hard, for experienced mountain goats interested in a quick endurance test. Once you pass the gate, immediately turn left up the side of a mountain. This is only a path because people have walked it so many times. Make your way up and up and up... there are about five humps as big as the single hump on the regular side, but without stairs. Then choose your way back. You can even turn around and manage those five humps back down which can be a lot of fun. That's how I like to do it. Just make sure you come with shoes that can grip... trust me, you don't want to slip.
Fryman Canyon, on the other hand, is casual. If you want a workout here, you've gotta make it up yourself. Sprint if you can. Or maybe just come here if you have a dog, though Runyon can suffice just as well (if not better). It's nice for a quick stroll, and has a great deal more greenery and excess trails to enjoy. The biggest plus about Fryman is the lack of traffic. Though, if you like pretty sights (Ladies and Cities) I suggest Runyon. The options are far superior there.
So again, if parking is a big issue for you, Fryman's a lot easier. But if you want the full experience including a built in workout, hit up Runyon. It's pretty obvious which one I prefer.
Runyon can be found on Franklin a few streets down from Highland in Los Angeles.
Fryman can be found just off Laurel Canyon in Studio City.
I hear there's a track by the La Brea Tar Pits, though I admit I don't have much of an interest in going there. I think it's just for jogging and I'm more interested in the elevation and the view.
Well have fun out there.