I should stress that the running I'm doing is beyond slow. Total strangers make fun of me. I think I could run alongside someone who is walking. I can't walk fast enough to get my heart rate to my target zone, so the running bumps my heart up. I use a heart rate monitor so that I know for sure what is going on. The whole point of this is to build up the slow-twitch muscle fibers in my body and improve my pace while keeping my heart rate static. The slow-twitch fibers use fat for energy. The fast-twitch fibers use glycogen for energy. The fast-twitch ones are the ones you employ the most when you are lifting weights, sprinting and doing activities at an anaerobic level. All activities actually use both, but anaerobic uses more fast-twitch and aerobic uses more slow-twitch.
I want to also stress that endurance activities appeal to me greatly. I wouldn't do this if I felt it was punishment or purely a weight loss trick.
Female, 5'3", 49, Starting weight: 163lbs. Current weight: 135 (more or less).
Starting squat: 45lbs. Highest squat: 167.5 x 2. Current Deadlift: 190 x 3