Heart Rate mysteries..pls help

Have you been running for a while, or are you just getting started? The idea behind base training is that you want to get your body used to exercising X many times a week (3 in your case), particularly if you are trying to get into decent shape before starting a more intense training schedule. Base training isn't going to make you a whole lot faster, but will help with the endurance and will prepare you for harder training in several months.

If you are in shape to do 3 runs a week at the distance you want already, you can speed up by doing interval sessions for one of your workouts and perhaps a longer run as one of the others. I'd suggest that you look through the training plans on the site here and pick one that fits your overall fitness goals.

What are you judging your "base pace" on?  your training zones aren't based on pace, although you will find that you typically have a certain pace for a given HR.  You're best to base your training paces on HR zones established from an estimate of LT (lactate threshold).  If you haven't done so yet I suggest doing an LT field test.  You can do it either on a track or find a 5-10k road race (depending on your pace).  I think the race is a better option because it will push you harder than you will push yourself on the track.  So the basic plan is to get a good 10min warm up and then begin the test.  You're looking to run a hard steady pace for 30min.  Ideally you'd start at a pace that you can just barely sustain for 30min and finish completely spent.  10min into the 30min effort you want to take a split on your HRM.  Your average HR for that last 20min will be a good estimate of your LT.  From this number we can establish all of your training zones and you'll know where to spend your training time.  For base building you want to focus on Z1 and Z2...for as long as you possibly can.  Depending on how patient you are and hw much you really want to maximize long-term performance I'd suggest sticking with base training for at least your first entire season.  Most people can't hold out that long but I honestly thing you'll be doing yourself a dis-service if you don't get a solid 3 months of strict base work in...MINIMUM.  Basically, the more the better.