Many athletes have a hard time with regard to intensity. We all work hard in our daily lives, and it's only natural to want to work hard at being a better athlete. Working hard at doing the right things is far different then working too hard in an aerobic sense. How hard should you train on a daily basis? Of course this depend on what time of year it is, what distance you are training for, and of course what your coach has on your schedule.
When I write a workout and I give an athlete a 'Zone1-2' workout, I expect the athlete to find the happy medium and train at a pace they could sustain all day. What I usually get when I check over a log is "..I went out too hard, and well I bonked.." or "..I was much faster on the first hour of my ride and then I kind of faded".
Run Pacing:
My solution is to do a better job of explaining 'exactly' what I want from my athletes. To provide you with a frame of reference, my LTHR (lactate threshold heart rate) on the run is about 168-171. My Zone 1 ends at about 145 bpm (beats per minute).
When I run training in a Zone 1-2, and I am running 'easy' which is like a 'guilty pace', I am around 140 bpm. That would put me close to the top of my Zone 1. When I am running 'Steady' (which I also call my Aerobic Threshold or AeT) I am usually around 148-150 which puts me about the middle of my Zone 2. With the exception of running tempo runs, I don't run over 155 in training. Sometimes I may see 160 on a steep hill, but I quickly get my HR back down by walking. Most of my 'Steady' running is done at 150 bpm, so for me that 150 bpm is my AeT or 'Steady'.
Your average HR during any particular run may vary by what type of terrain you are running on but take notice of your HR when you are running 'Steady' on the flats; this HR should be in the comfortable zone where you can stay all day.
Now, having said all that; let me back up for a minute. Running 'Steady' to me may be much different for you. You may find your 'Steady' zone at the high end of Zone 1. Or you have may find your 'Steady' zone at the top end of Zone 2.
You should be able to see a marked difference between running 'Easy' and running 'Steady'. When I am around 140-145 it's a pretty easy run. Once I jump over that magical number of 147-150 I see a change in my breathing and my effort is increased. I can still run aerobically here, don't get me wrong, but I am no longer running 'easy'. You should feel and even hear a change in your breathing pattern. This is when you are running 'Steady'. Once I get into this zone, I don't look at the HRM (heart rate monitor) too much, I know where I am effort-wise and the HR will usually settle between 147-152. Your objective should be to get comfortable enough with the HRM that eventually you can look at it and know exactly what your HR is. By monitoring your breathing you will know when you have crossed that line of 'Easy' to 'Steady'.
If you can follow the above and practice the discipline of just running 'Steady' when you are assigned those 'Zone 1-2' runs, you will improve your running. Spend as much time as you can running 'Steady' and it will pay off.
Bike Pacing:
Now how does this apply to biking? Once again, to provide you with a frame of reference, my LTHR (lactate threshold heart rate) on the bike is about 155-160. My Zone 1 ends at about 141 bpm (beats per minute).
When I bike train in a Zone 1-2, and I am riding 'Easy' I am around 125 bpm. That would put me close to the top of my Zone 1. When I am biking 'Steady' I am usually around 135-140 which puts me about the middle to the top of my Zone 2. With the exception of climbing hills, I don't run ride over 140 in training. Sometimes I may see 145 on a steep hill, but I quickly get my HR back down by spinning easy. Most of my 'Steady' or AeT biking is done at 135-140 bpm.
The fun thing about cycling is that you can tie in your HR to your cadence and then to your power (in watts) if you access to that type of equipment. I enjoy being on my Compu Trainer pedaling along at 125 bpm, and seeing my watts at 200 and my cadence dialed in at 90 RPMs. Riding 'Steady' becomes easier the more you do it.
Work on the difference between 'Easy' and 'Steady' between now and next your next build period and you'll go into your A race feeling more prepared than ever.