Two hours plus that is what I did today. Started about nine just to let things warm up a little. Wasn't bad at all felt like I could have done another 2 hours , good feeling to have. I was dressed properly for this one. Hoody, gloves, tights and my jacket by Nike. This jacket is amazing, it looks like the lining of a coat but the darn thing keep you so warm, its unbelievable something so thin can do such a great job. My feet felt nice and warm. As you can seen I was really pleased with how comfortable I felt running today in 26F that felt like 16F!!!