How Long Should My Runs Be to Lose Weight?
"Ideally, one needs to be exercising at at least 65 percent of their maximum heart rate for 30-90 minutes to burn calories from fat sources," said Chris McGreer, MS, NSCA, personal trainer and exercise physiologist at Northwestern Medicine Delnor Health and Fitness Centre. (Here's how to find your max heart rate.) However, that comes with a ton of caveats. The first and most important factor to look at is your current fitness level. "Running is an incredibly strenuous activity that the body needs to be built up to handle," McGreer told POPSUGAR.
Running is high-impact, full-body, and tough on your cardiovascular system and joints; pushing yourself too hard when you start can quickly lead to injury or, at the very least, extremely uncomfortable runs. Neither of those outcomes is going to help you lose weight; you either won't be able to run or you just won't want to.
If you're just starting, it's imperative that you take things slowly. Start off walking and adding in slow jogging intervals; as you get more comfortable, you can increase the amount of time you spend jogging and work your way up to running the whole time. Once you've established a stable pace, you can start to think about the length of your sessions.