Are You Running Too Fast?

by Laure Van den Broeck Raffensperger

In July 2018, SMAC sponsored me to attend the RRCA-level 1 coaching course in Bloomfield, CT. It was awesome! Two days were crammed full of running topics, and parts of it were pretty basic. No top-secret information, or hot-off-the needle new sports science. However, that in itself turned out to be significant. My big insight for the weekend was: sometimes training principles are so basic that they get overlooked, because in all their simplicity, they don’t feel ground-breaking or life-changing enough for people to remember them, or pay them much attention. And yet, they are cornerstone principles, the foundation of our everyday training.

Take this rule-of-thumb, for example: hard days hard, easy days easy. You’ve probably heard it a million times, but what does it really mean? What constitutes “easy,” and how often should you run at this pace?

An “easy” effort means a conversational, or aerobic pace. If you have never really paid attention at how slow this pace should be (71–80% of your maximum heart rate), it’s going to feel too slow. You’ll think it can’t be right. It’s too slow! How could you ever get faster running at this pace? Even if you do know what your conversational pace is, it’s very likely that you’re not running at this pace for 80% of your runs (80% easy and 20% hard is more or less the recommended training proportion). Sometimes you can’t help speed up running with friends, when the speed dial creeps up because nobody wants to seem slow, or when competitiveness starts driving the pace. Easy conversational miles are also sometimes mistaken for “junk miles” (that’s what I used to think, too) and runners choose to avoid them, and log faster “quality sessions” instead.

The junk miles, however, are not the slow miles. They are the moderately-paced miles that neither belong in your slow, conversational 80%, nor in your fast, high-intensity 20%. They are the miles that you run too fast without noticing it. It’s true, they give you immediate satisfaction because you feel like you had a workout at a pace that makes you feel like a pretty decent runner. It’s tempting to run too fast, especially if you don’t have a lot of time to run and you still want to log a certain number of miles.

In the long run, however, running too fast for too much of the time can stop your progress. That’s because only true “conversational pace” miles will really allow you to build up a big aerobic base: it’s the process of your body developing its cardiorespiratory system. What happens to your body is this: your heart increases in size and strength, your body starts growing more capillaries to carry the blood to and from the hardworking muscles, and your total blood volume increases. Meanwhile your muscle fibers get bigger and will add in more of the little cellular organs that generate the fuel (ATP) needed for their contraction. These little organs known as mitochondria, make this precious ATP from the stores of glycogen (carbohydrate) and fat that are available. If you have more of the mitochondria-making ATP, your muscles can work harder and faster and not run out of fuel (and the sound of muscles running out of fuel is: BONK).

This stimulus to mitochondrial development occurs most when you train at an easy pace. When your body has had enough time to adapt to running at a conversational pace, it becomes more efficient: you’ll be able to run more, you’ll likely run faster and with less resulting soreness. If you have never built an aerobic base on conversational miles, or picked up after a long hiatus without re-building it, your body isn’t really ready to do what you’re asking from it, and you find yourself at a plateau and unable to improve. An even worse effect of running too fast, too much of the time is the risk of injury, especially if you try to run more and more miles at a pace that you think is “easy” but is really not.

If your 80% of training is too intense, it’s not just your aerobic base-building that is compromised, but also the 20% of your training that is meant to be hard. Why? You can’t run a good quality interval, tempo or VO2-max workout when you’re already tired from running those “easy” miles! Remember that a hard workout in itself does not equal improvement. The right formula is this: A hard workout + recovery = improvement. Your easy runs should help you recover from hard workouts so you feel rested before the next hard workout. If you limit the number of hard workouts to twice a week, and you run easy (no cheating) between hard days, then your 80%–20% volumes will be about right.

So how do you calculate your “easy pace”? The simplest way is to make sure you can breathe and talk easily while you run. A more reliable way to know if you’re in the right zone of intensity (aerobic, easy, and conversational all mean the same) is to keep track of your heart rate. If you know what your maximum heart rate is, you can find your training zones. For example, if your maximum heart rate is 180, your aerobic zone is between 127–144 BPM (71%–80% of 180). Most running watches now have wrist-based heart rate monitors and display training stats that get more detailed all the time, so you might get some useful data there.

One of the things I love about this sport is that you never stop learning, especially about what works well for you. If you’ve never evaluated how hard your runs are, on a day-to-day basis, then stop and give it some thought… Maybe it’s time to slow down!

Laure is a SMAC Board member from Greenfield 

Originally published in The Sugarloaf Sun May/June 2019 issue