For the last couple of weeks, I have been training at 135 – 142 heart rate for most of my weekly training runs. With that heart rate range, I can maintain about 9:30 to 10:00 minute per mile pace for 5 – 6 miles. That’s about a minute and 15 seconds slower than my marathon pace. It takes a practice to maintain the speed as I have been accustomed to push myself to do 8 minute miles or into 7:45 minute mile pace on my previous long runs.
The reason was that I recently re-discovered the Dr. Philip Maffetone’s Magic 180 Rule. It’s about how low intensity aerobic workout is the key to increasing aerobic capacity. At about 70% of maximum heart rate, runners can build their aerobic capacity, improve their running mechanics, reduce the chance of injury, and allow for faster recovery time, hence making it possible to put in more miles. And these low intensity easy runs should make up about 80% of training.
The name Magic 180 comes from the fact that runners are to subtract their age from 180 to get their target training heart rate, and adjust it by their running history, illness, and physical readiness.
Dr. Maffetone originally calculated these numbers for individual runners, but eventually saw patterns in them, and created the Magic 180 rule. (You can read more about it here.)
For me, that meant I needed to train at about 135 – 140 heart rate range to optimally increase my aerobic capacity, which I have not been doing much. 90% of my runs were tempo runs at 8 minute mile pace. I haven’t been measuring heart rate on recent runs, but I bet that they were around 150 – 160 range.
So I decided to give the Magic 180 rule a try. I started running most of my runs at 135 – 140 heart rate range. It’s been two weeks since I dusted off my heart rate chest belt, and started wearing them for my runs.
Stay tuned to find out how the Magic 180 rule is working for an average runner.