If you’re anything like me, you’ve probably heard lots of distance coaches, running columnists, exercise physiologists, and running store employees urging us all to run slower on our easy runs. The reasoning is simple: the slower you run on your easy days, the better you will recover and will be more prepared to run a hard workout later. Also, you actually improve during the recovery phase, so it makes sense to run as easy as possible to ensure that your body actually recovers instead of breaking down even more.

This is all well and good, and I try to take this to heart. As I have improved over the years, my easy run pace has certainly declined. For instance, when I was in college, and barely a 17:30 runner, I would typically run around 7:00 pace for most of my runs. Now that I am in the low-16-minute range, it is very unusual for my easy runs to be faster than 7:20 pace, and my recovery runs can be as slow as 9:00 pace.

Recently, however, I read something that even further reinforced the idea of running slowly on easy days. First, let me preface this by saying that I have actually been wearing a heart rate monitor for my runs in the past week. I did this because I am re-building my mileage after taking a week off, and I donated blood in that off week. So I want to be careful about making sure my runs aren’t overly taxing, because I am lacking some red blood cells, and running more than I have in a few months.

Yeah I look like this

With the understanding that I am, for once in my life, thinking in terms of heart rate, consider a hypothetical runner. Let’s call him something generic like Matt. This Matt character has an aerobic zone of 130-150bpm.

HR Pace
130 8:00
140 7:30
150 7:00

A heart rate of 130 equates to an 8-minute mile, 140 is 7:30, and 150 is 7:00. That means that while his heart rate is in that zone, he is increasing his aerobic fitness and becoming a better runner. Distance running, after all, is 90% aerobic and 80% mental. Matt runs 70 miles per week at an average pace of 7:00 per mile. That means he is running for 490 minutes, or 8 hours and 10 minutes, at an average heart rate of 150bpm, at the upper end of his aerobic zone.

Suppose there is another runner, identical in physiology and fitness as Matt. Let’s call him something completely different, something that nobody would ever confuse with Matt. How about George? George also runs 70 miles per week, but he runs them at 8:00 pace, which takes him 560 minutes, or 9 hours and 20 minutes. He is still within the aerobic zone that he and Matt share, but he is realizing an additional 70 minutes of aerobic exercise!

This is exciting stuff, right? Both are increasing their aerobic fitness, but George is doing over an hour of additional stimulus! But wait, there’s more! As we all know, the slower you run, the farther you can go. So, George finds that he can now up his mileage to 80 miles per week without any undue stress. So now, he is running for 640 minutes a week, or 10 hours and 40 minutes! Compare that to poor old Matt, who still can only manage about 8 hours of running before he feels worn down. Who do you think will be the better runner in three months? Well, nobody can actually say, because this is a hypothetical situation and Matt and George are figments of our imagination.

Now this little mental exercise is of course not real life, and in reality, things are never this simple. But, the fact remains, that as long as you stay in your aerobic zone, whatever that may be, running slower will definitely allow you to incorporate more time running, and might enable you to increase your mileage as well. Plus, the easier pace will cause you to recover from your hard workouts and races better too. It’s a win-win situation!

Categories: Matt's Blog


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