If you’re just getting started in running, 3-4 times a week is a good place to start. Build up to 20-30 minutes of running (or run/walking) and add in a couple days of cross-training if you feel good and want to do more. Most coaches and experts recommend increasing your mileage by 10% each week. Doing too much too soon is an easy way to get injured, and the 10% rule is a good way to prevent that. It may feel like you aren’t adding on enough each week, especially in the beginning, but trust us.
Start slowly and build up to five days a week. Some people may fall in love with running and want to get out there for at least a few minutes every day, but it’s important to take at least one rest day. Your body needs time to recover.
Once you feel comfortable with your running routine, you can check out a training plan and sign up for a race! While it’s definitely possible to just go from nothing to training, most programs assume you are running at least a couple days a week. The Couch to 5K program is a good one if you want some guidance and you’re just starting out. Most of these start as more of a run/walk program and can be helpful for people who want more of a structure or plan.
As with any running program, listen to your body. If four days feel like too much, try two or three. You don’t want to get injured when you’re just starting out, so take your time and you'll end up building a strong running foundation.