Jim2's Running Page

Aerobic Conditioning Pace

About Me
Favorite Links
Contact Me


A runner on the Running Times forums (Skim) had not run any races and was looking for pace guidance for aerobic conditioning runs. He said that he was just doing all of his running at a 7:30 pace, but he wasn’t running high mileage. He wanted to know if it was OK to continue to run at that pace as long as he was able to handle it. His post drew a recommendation that he should run a 5-10k race to establish a baseline, and then use a running calculator to determine proper training paces. Since a race was not available to him, he ran a 3-mile time trial on a track. Subsequently, another forumite posted the following question on the Runner’s World forums:


“Does anyone know a more scientific method for determining GA (General Aerobic) pace runs (per Pfitz) than midway between LT and long run/easy run pace?”


The following was my reply to him.


I can tell you what Bob Glover says in his book, “The Competitive Runner’s Handbook”. He defines a range of what he calls "easy" and "moderate" aerobic conditioning paces that a runner should use for all training other than speedwork. I suspect the middle of his range is what you are asking for. I'll quote from the 1999 edition of his book.

"Most runners monitor training by pace per mile. You should have a flexible range for training pace: from easy to brisk.


Brisk Pace: 10k race pace + 1 min (or 5k race pace + 1 min, 15 sec).
Base Pace: 10k race pace + 1 1/2 min (or 5k race pace + 1 min, 45 sec).
Easy pace: 10k race pace + 2 min (or 5k race pace + 2 min, 15 sec).


These pace formulas are only estimates. They should be determined by your present fitness level for a 5k or 10k race. Be honest! These paces are most accurate for experienced, fit competitors with an adequate mileage base. If your paces seem too easy based on these formulas, perhaps you can race faster. On the other hand, if training paces based on these formulas seem too hard, perhaps you overestimated your fitness level.

Base pace is the comfortable training pace you naturally settle into for an unstructured run. This pace should be the target for most runs since research indicates it is the best intensity for improving aerobic fitness. It equals about 70 to 75 percent of maximum heart rate and is a conversational pace.

Brisk pace is the estimated fastest pace you can run at and still stay within your training heart range. You'll be at approximately 80 percent of maximum heart rate and may not be able to talk in full sentences. This is too fast for a daily pace. It's only a notch below tempo pace. Do not run this fast on consecutive days, the day before or after hard runs, or too frequently. One or two brisk-paced runs of 30 minutes to an hour each week will help keep you fit if you're not doing regular speed training, or of your mileage is too low.

Easy pace is recovery running. It equals approximately 60 to 70 percent of maximum heart rate. Use these runs the day after hard workouts and races, and whenever you're tired and want to take it real easy. Usually these are short runs of 3 to 5 miles, although some runners may do long runs at this pace."

Let's use skim's 3-mile track test that he ran a couple of days ago as an example and see what Glover's guidelines would yield for training paces. According to the calculator on Ryan's (hillru5’s) website, his 18:54 time for 3-miles equates to a 40:54 10k race time (6:35 pace). Glover's guidelines would call for a brisk training pace of 7:35, base pace of 8:05 and easy pace of 8:35. Glover's base pace is very close to the 8:07 "easy" pace that Ryan's calculator yields. This is the pace that should be used for most, but not necessarily all, runs other than speedwork. I think it's clear that 7:30/mile is a bit fast for a standard, daily training pace for skim....assuming the 3-mile test was reasonably valid.

In the absence of a road race, such a test is certainly useful for guiding training paces. However, it's difficult to run your best alone on a track. It's very possible that he could run even faster in a race environment. Also, his test run wasn't very well paced. The first mile was too fast, which probably cost some time in the second and third miles. I suspect that he could run the 3-miles faster with better pacing and a little competition. A second, better paced time trial might shave some time and bring his base, brisk and easy paces down another 5-10 seconds. Thus, a test such as skim's might lead to training paces slightly more conservative than necessary, but that's better than paces that are too aggressive.

I'm not sure if any of this is really addressing your question, as opposed to just rehashing skim's issues. Maybe another way to go at it is to describe how I judge my "general aerobic" paces. After almost 25,000 miles logged, I pretty much know how my "base pace" runs should feel by breathing level.

A well paced "base pace" run for me has me breathing at a 3:3 rate (inhale for three strides and exhale for three strides) until 2/3 to 3/4 of the way through the run. I then have to shift to a 3:2 breathing rate in order to maintain the same level of running intensity until about 90% of the way through the run, when I shift to a 2:2 rate for the last 10%. If it becomes apparent that I will have to shift to 3:2 earlier than 2/3 the way through the run, then I know that my pace is too fast and I slow down for the remainder of the run.....and I can pretty much tell if that is the case by 1/4-1/3 of the way through the run. For me, these runs are at about 75% of HRreserve.

When I run at "easy pace", my breathing rate stays at 3:3 throughout the run and my HR stays in the range of 65-70% HRreserve.

A "brisk pace" run has me at a 3:2 breathing rate by 1/3-1/2 way through the run and at a 2:2 rate for about the last 20-30% of the run. The last half of the run is at 75-80% HRreserve.

My method isn't very scientific, but it is a method that has served me well over the years.

We need training paces to guide us. But we also have to remember that everyday can be different. What is an optimum base pace one day might be a little different another day. Many variables can affect it....temperature, humidity, how much rest we have had, mental and emotional stress level, how hydrated we are, what we had to eat in the pervious 24 hours, etc, etc. It's good to have a way to judge level of exertion/intensity other than just a watch on our arm. That's one advantage that those who train by heart rate enjoy.

Incidentally, I think it is a mistake to try to run 100% of non-speedwork mileage at the exact same pace, especially during a base building phase of a training program. I think it is better to use more of the aerobic conditioning range....measured either by pace or HR. Train at the same pace all the time and you are training to run at that pace. It's better to use a variety of training stimuli. Phases of the program that include regular speedwork provide variety; thus exercising the range of aerobic conditioning paces isn't so important. But, I think it is important when base building. That's why I said in an earlier post in this thread that base building is a great opportunity for "free form" running, including some fartlek running.