I think I can help! I was in the process of training to run a marathon but then I got pregnant and miscarried. Anyways.... I love running. It makes me feel great. I am thin also but I just love the way it makes me feel. Running is a bit hard on the body at first. Take it slow, only run 30 minutes. And you won't be able to do it every day at first due to soreness. Make sure you have good shoes. I had shoes that were tennis shoes and running in them gave me shin pain. Someone at a store could help you. I recommend run at about 3.5-4.0 miles per hour for about 3 minutes, then walk for about 3 minutes. It will seem easy at first, but you need to take it slow to last the whole 30 minutes. And if you really don't feel like you can run that long, insert more walk breaks. All running books will tell you that walk breaks are very important. And ofcourse, drink alot of water and don't run on a full stomach. Good Luck, stick with it and you'll love it.