It’s important to be reminded from time to time that we have a responsibility to our fellow human beings to teach them the true meaning of aerobic training. Remember that a few words at the right moment could be the light in the darkness that rescues someone from months, if not years, of trendy, high-intensity gym-based workouts when all they want to do is finish a little higher in their local 5k.

I jest, of course.

I have no right to criticize someone else’s workout regimen, especially when it’s a regimen I have never tried for myself. If people want to do CrossFit or Insanity workouts or something else, who am I to criticize them? After all, it’s great that they are challenging themselves mentally and physically, and forming communities of mutual support and encouragement to do so. Good for them.

But I do find it interesting that when I find myself talking to someone about training for distance running, as often as not they have no appreciation for really basic principles of aerobic fitness.

The other day I was at lunch with work colleagues and I happened to sit next to a guy I’ve known for ten years — I’ll call him Ken — who is several layers of management above me at Nuance, where we both work. Ken is a great guy and has a terrific work ethic. In his professional role, he takes on a lot of the numbingly-detailed planning tasks that have to be done but that no one else wants to do. He is an example of a leader who never asks his staff to work harder than he himself does.

Ken is also a pretty good athlete, not the most skillful or graceful, perhaps, but determined and hard-working. After playing more traditional “ball” sports for most of his life, Ken started running a few years ago, and got to the point where he could run a half marathon and maintain a decent seven-and-a-half-minute per mile pace. Unfortunately, the demands of his job — late hours, extensive travel, and managing people across multiple time zones — have frustrated his efforts to train consistently. It probably doesn’t help that he recently bought a house and insists on doing a lot of work on it himself.

So anyway, I was sitting next to him at lunch, and  I asked him whether he had been running much lately, and whether he had any specific goals. He acknowledged that he hadn’t been able to keep up a regular routine of running, but that he had been doing CrossFit a couple of times a week, and had fallen in with a group that had competed in a Tough Mudder event. And then, he admitted that what he really wanted to do was get back into good enough running shape that he might be able to win the sparsely attended annual 5-mile road race in his home town (not identified here so that none of you will show up and make his task more difficult).

I asked him about his training, and it turned out that he did two kinds of runs: regular runs on the roads, in which he tried to run closer and closer to his goal race pace for as long as possible, and occasional sessions at a track, in which he tried to sprint for a lap or half a lap at a time.

It sounded miserable to me. Every day, it seemed, he was just pounding away at the edge of what he was capable of doing. The regular runs were relatively short (for a distance runner) but long enough so that he never actually ran goal race pace. The track workouts were almost certainly 80% anaerobic.

So I talked about how, once you had established the basic ability to run mileage, there was this concept of maximal aerobic pace, a physiological variable that could be improved by training at a high fraction of that pace. the idea, I kept saying, is to find ways to stimulate increases in aerobic capacity. Short intervals and CrossFit workouts are intense training, I acknowledged, but they focus on different energy systems, and thus aren’t particularly effective for learning to run at a sustained hard pace for several miles. If he really wanted to win that local road race, he needed to train the energy system most in demand for a race lasting 30 minutes.

It reminded me that I used to talk about “nature’s perfect workout” for distance runners: 3 minutes hard, 3 minutes recovery, repeated enough times to achieve 20-25 minutes of running at the desired pace. It struck me that almost every “VO2 Max” workout can be viewed as a minor variation on that theme.

Lunch was over, and there was much more to say, but I knew enough not to keep talking about aerobic and anaerobic thresholds, the details of managing the recovery intervals, and other workout arcana. I really wanted to leave Ken with a simple picture of what we had been talking about: train the energy system that you’ll need most by doing workouts that target aerobic capacity, not workouts that merely felt hard. I told Ken that if he had the time and the interest to do them, I’d gladly give him a series of workouts to do just that.

And as we headed back to the office, I shared the other “secret” of road racing success. I promised that make sure none of my running friends knew about the race.