How do you know if your base training is working?

Base training is a funny thing.  You want to go hard but you know that you should go long and easy to build your base aerobic fitness.  But how do you know if are going hard enough to make a difference on your base or if you are going too easy and just wasting your time with junk miles?  Or maybe you are going too hard and not working on your base at all?  Dr. Philip Maffetone wrote an article many years ago about base training but is was mainly focused on runners, and it was around the time time that heart rate monitors had just come out well before power meters.  It was called you “Want Speed?  Slow Down!“.  I love this article because it is so clear about how to build your base.  Key factor:   No anaerobic training and do lots of time just below your aerobic max heart rate, then as you get better raise the power but continue to use the same heart rate.  But how do you find your aerobic max heart rate?  Maffetone gives a formula based upon his research.  If I use his formula my aerobic max heart rate would be 180-40+5 = 145 bpm.  However, I know that my aerobic max heart rate is at 152 bpm because of the metabolic/VO2 max testing I have done.  So for me when I am targeting my aerobic base, I keep my heart rate between 140-150 bpm.  On the trainer, I adjust my computrainer output to maintain this level during my longer intervals. 

The other article that I like on this subject is “The ‘slow component’ of VO2 – understand it to go faster!“ from Andrew M Jones on the Peak Performance website.  On Saturday, I was doing a 20 minute interval that shows a great example of the slow component of VO2 as shown in figure 2 from the article from Andrew.  My plan was to do 300 watts for 20 minutes.  As you can see below in chart, I held the 300 watts for the 20 minutes but my heart rate continued to rise through the whole interval.  The dotted red line is at 150 bpm or my aerobic max heart rate, and you can see how as I hold the power level my heart rate continues to rise to 162 at the end of the interval.  This looks a lot like the “heavy” situation in figure 2.  When I am doing a FTP interval I try to get my heart rate up to about 168-170 so this was not hard but the VO2 slow component was building as my interval progressed.

Now for an example of training at the moderate level as shown in figure 2 and training at my aerobic max heart rate zones.  Today, my goal was to ride a 3 x 60 min intervals but adjust my power to hold between 140 and 150 bpm.  Below is my first interval with my heart rate zones indicated with the red dotted lines and the yellow dotted line indicates 270 watts.  For the first interval, I was able to hold around 270 watts while maintaining my heart rate below the 150.  There was some upword drift because I was doing these on the trainer.  The fans can only cool me so much on high.  This interval compared to the one above shows how staying below aerobic max is a key factor to avoid the Vo2 slow component.  I am sure that my heart rate would have continued to raise when I was holding 300 watts yesterday but at 270 watts, I can ride all day in this heart rate zone.  Since today was longer day, I completed 2 more similiar intervals while keeping my heart rate in the same zone.


By staying below your max aerobic heart rate you will be build your base if you put in the time and work exclusively on this system for 3-4 months.  You will know it is working when you have to increase the power to stay within your heart rate zones.  I am finding it easy and easy to raise the power level on my 3×30 intervals while staying with in my 140-150 zones. 

Base training is training just below hard and burns much more fat and less carbs, which is what you want to have happen.  Burning more fat is great, but it also does not make me so hungry like the way that LT interval blocks do.  This helps me so that I can focus on dropping a few pounds. 

LT work is hard work and should be done after your base training starts to platau after about 3-4 months.  This is the time then to do LT/FTP intervals.

Ride Hard,