I was a casual runner in college, so 20ish years old and I would run 4-5 miles a day. I started at 6mph and eventually I made it up to 6.5/6.7 for some intervals if not the whole run. That was a good 12 years ago. I've started trying to run again through the 10k app, but I don't know how fast I should really be going. My default is to walk at 4 and run at 6, and I've been relatively inactive (having kids and not going to the gym) for the past few years so running at 6 is hard, but not impossible- but I feel like any speed is going to be hard. I am improving, but someone told me today that 6 might just be too fast in general and I have no real concept of how fast to go. Any tips or suggestions appreciated.