How far is far enough?

I love the way I feel after a good run. It's hard to explain to someone who doesn't run, and needs no explanation to someone who does.

But, how far do you have to run to 'feel' like you ran? My schedule is bursting at the seams right now, and I don't have a lot of time during the week to run like I want. I ran a quick mile on the treadmill today warming up for a weight session and trying to get back to running every day. But, I don't 'feel' like I ran. I'm sore from the combined weight training sessions of yesterday and today, but I don't have that boost of energy and satisfaction that comes with a nice run.

I guess it depends on how far your long run is, and how far you can run at a time. I'm running about 12 on my long run days (nothing compared to my 20 milers preparing for my marathon last spring), and can get away with it with minimal soreness. So, I feel like I need about 4 or 5 miles to 'feel' like I ran, and more than 12 to feel like I ran long.

Did I mention that I hate daylight savings time, and all it does to my running schedule? I may have to get friendly with my treadmill again, and start getting some miles in before anyone wakes up and my day speeds into hyper drive.

One of my favorite places to run. This is where I go for therapy.