Observation-MAF treadmill runs

Just updating with an observation.  So, treadmill running has always seemed easier to me than outside.  I know, no wind, hills, belt propelling you.  

But I mean, like waaaayyy easier to me.  I have my incline set at 1.5%, so we have the difference covered.  

I've always noticed that my runs outside tend to be about 20 seconds slower, with the same perceived effort, as my treadmill runs.

Well, now I have some proof.

I've been monitoring my heart rate this week, and with my shorter 5 mile run, after a mile warmup, I had to stay at at 7:30 pace to stay in my MAF zone of 138-148.  And, this was on the low end.  

For my longer run on the treadmill today, of 12 miles, I had to stay in about a 7:30-8:00 pace to stay in my range.  

Very interesting to me, but makes sense and correlates with my perceived efforts.  

So, there may be something to this.  

I'm anxious to see if I change any in the next month :)