I’m about six weeks in to a more intentional relationship with heart rate training and wanted to share what I’ve been doing.
You may be familiar with the MAF method (Phil Maffetone’s low heart rate training method). Basically, you find the point where your heart rate shifts from aerobic to threshold and attempt to keep all of your runs easy, in the aerobic zone.
By following this method, many runners have become stronger and faster because they build a solid base of mileage and see their paces slowly increase at the same low heart rate.
I have never had patience to actually try this method as you need to eliminate all threshold and interval workouts, and those are my favorites!
However, when I upgraded my watch this fall to a Garmin 235 and heart rate tracking was happening automatically, I began to pay attention to what was happening.
The 80/20 Rule
Many coaches guide runners with the 80/20 rule and this has been my coaching and training philosophy as well. The idea is that by keeping 80% of your running easy, you can still build your aerobic base while building in the 20% of harder work at either threshold or interval pace.
I noticed that sometimes my heart rate was nice and low on my easy days, and sometimes it was actually inching into the threshold zone for the second half while it still “felt” easy.
The problem with this is that my body was not getting as much recovery from the harder days as it should have been getting and the 80% was actually more like only 50-60% easy which makes it harder to build an aerobic engine (and easier to hit burnout…spoiler alert, which happened!)
So in January, I decided to go for it- force myself to stay in the aerobic zone on my easy days.
How do you calculate the easy aerobic zone?
What Maffetone suggests is that you start with 180 and subtract your age to find the maximum heart rate for you to stay within the aerobic zone. For me, that’s 143. If you have been training for several years and have been relatively injury free, you can add 5. For me, that’s possibly up to 148. (You can find more details on his site).
Maximum heart rate is different. The traditional belief on max heart rate is 220- your age, although there are arguments that this is out of date.
I have not been worrying about my max or threshold heart rate zones. On hard workouts, my heart rate is in those zones and it is what it is.
But I have been working hard to keep my easy days truly in an aerobic zone.
As I noted in my workout recap, I feel more energized and recovered than usual despite increasing miles fairly significantly. In January, I got my weekly miles back into the 40s consistently with two weeks at near 50 miles per week without feeling like I’m in marathon training or working too hard.
I have a marathon on the calendar for the fall but for now am just wondering if I can increase my aerobic engine with the increase of easy days.
According to my Garmin, it’s slowly working. Remember how over-trained I was starting to feel in the fall? My heart rate was higher than usual on easy days and Garmin adjusted appropriately to tell me my VO2 Max had actually dropped.
I took several recovery weeks and since rebuilding with careful attention to aerobic running, my VO2 Max increased again and even surpassed where I was in the fall.
I’m going to give this a try for the year and see where it takes me!
Challenges of low heart rate training
There have been a few (hot) treadmill runs where I had to stop and walk to bring my heart rate down before it finally settled in a reasonable aerobic zone.
There have been a few threshold workouts where my recovery period took longer than usual to get my heart rate back down so I could run the recoveries in an aerobic state.
There have been days where my heart rate was staying low while I ran 8:20s and days where I had to slow to an almost 10 minute mile to keep it in the aerobic zone.
It’s not easy slowing down when I otherwise feel good, but it’s forced me to be much more in tune with my body and the recovery process.
How I track it
So far, I’m only using my watch. On easy days, I switch to the heart rate screen and glance at it every few minutes to keep myself honest. I’ve read that chest strap monitors are more accurate than wrist monitors but if it’s off by a few beats, it still gives me the general idea of how hard I’m working.
Again, I’m not officially doing MAF and going all in- I’m still doing my interval and threshold work. I’m simply forcing myself to slow it way down on the easy days (or speed it up, as the heart rate allows for that day).
Have you used heart rate training or tried MAF?