Quote Originally Posted by tamara_69
What I want to do is a duathlon sprint in June. It's short, 5K run-12M bike-5K run. But the run portions are going to be my real struggle. My goal is, I guess, prolonged aerobic runs. Right now, I walk and my heart rate doesn't go above 110, and I run and I can't keep it below 160. And the running is SLOW, an 11 minute/mile pace! There's no middle ground. I would love to work up to 3 5-mile aerobic runs per week. And be able to enjoy them!

Another question--in training people talk about a long run, once a week. How much longer than the other training during the week, and how much slower?
The long run is in preparation for something else even longer. For example in training for a marathon you might run 6-10 miles several times a week and 13-18 miles once per week. Never actually running 26 until marathon day. Since your goal is a 5k (3.1miles) and you plan on training at 5 miles several times per week, you don't need a longer run.

What's wrong with a HR of 160? I run 4-6 miles and am usually 160-170 and I can talk the whole time. Can you talk? If so, why slow down?