Running in Madrid
As far as cities go, Madrid is of moderate size, yet it boasts a large number of parks and recreation areas for pedestrians and athletes alike. Although one can get plenty of exercise simply walking from one place to another, the city also caters to runners. Parks such as Retiro, Parque de Oeste and Casa de Campo offer an escape from the stifling city smog. Granted, these major parks don't attract just runners, and depending on the weather or the time of day you may have to fight your way through crowds to get a decent run in. Still, both novice and seasoned runner seek to gain from investigating some of Madrid's more popular trails.
El Buen Retiro Park: The Retiro is a great place to start for anyone who's new to running in Madrid. It features wide, easy-to-navigate trails, and its picturesque landscape, complete with a small boating lake, rose garden, and the famous Glass Palace, make for a pleasant run. The picturesque setting means there is a high volume of tourists as well as native recreationists. A complete loop around is about 4.5k, or 2.7 miles.
Parque de Oeste: Another great park, and much less crowded than Retiro. Its main attraction is Templo de Debod, an ancient monument that's lovely at dusk. Be warned, however; the park is dangerous at night. A mid-to late morning or daytime run would be your best bet. Once around will bring you up to just about 5k, or 3 miles.
Casa de Campo: This vast expanse of undeveloped land is considered one of the best places to run in Madrid. It features a number of extensive trails with varied terrain--great for anyone who loves hills. Depending on the route one loop around would be 10k/6 miles or more. As with Parque de Oeste, though, it's best to run here during the daytime.
Parque de Canal Isabel II - For those interested more in speed workouts, the park at Canal Isabel II features a 1200m track, with markers placed every 100 meters. Of course, the loop is more commonly used as a walking path than an actual track, and runners looking to knock out a workout will often need to dodge pedestrians along the way. Regardless, the park (which is also home to a small driving range, for those interested in golf) is well-maintained, and crowds can easily be avoided in the early morning.
It goes without saying that these are just a few of the many options for runners in Madrid. Many neighborhoods have their own smaller parks, and there are plenty who brave the city streets as well. Unfortunately, Madrid is known for its poor air quality; generally speaking it's best to run a) in the morning or evening, and b) as far away from traffic as possible.