When you first begin running, your legs take a beating. Don’t be afraid to mix it up through the week. When I began running again (after a 3 year break), I jogged really easy watching my heart rate and walking on one day. The next day, I got on the elliptical or ArcTrainer and used my HR monitor to get in the 65-75% zone.
I cannot stress staying in that aerobic zone of 65-75%. You will get in shape quicker if you target that range of HR. I didn’t believe it either. I purchased a treadmill many years ago so I could run at home. I ran as fast as I could…for the length I was set out to run. The bad part was I ran in the 85-90% of my max heart rate. It took me 4 or more weeks to reap the benefits. After my long break, I made it a point to stay in the aerobic zone and I saw results in a week!
Just stay consistent with your aerobic activity and feel free to mix in some “cross-training” to break up the monotony and give your legs a little break.