You can start out with 40 mins until you feel comfy enough to hit 1hr. Start out with what is comfortable for you. Then after a week, increase the incline and walk for 5 mins then lower incline and walk at 3.0 for 1 mins. Then run for as long as you can. Basically during your workout you should switch up levels of speed and incline. You can try walking backwards and sideways (hold on until u get comfy) this is so u dont get bored. Also try walking with light dumbells. stay hydrated with water/ u dont need sugar laced sports drinks. good luck to u. hope i helped.
I did the same thing a couple years ago. Try working up to being able to jog about 2 miles or 30min. atleast 5 times a week. Make sure you can breath and be able to carry on a conversation while jogging, this will ensure your heart rate is at its prime for best weight loss results. Also make sure you are drinking plenty of water, that alone will help you to shed lbs.
