30 Days of Low Heart Rate Running (Maffetone Method)

For a month I have been attempting to reboot my fitness by following the Primal Diet and running with Dr. Phil Maffetone’s low heart rate based training method, simply known as the “Maffetone Method” to build up my aerobic base and keep my runs in the fat burning zone. Click here to read about why I have made these changes to my diet and workouts, and with this post I want to share my experiences during the first few weeks.


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As I try to build a strong aerobic base AND burn fat, this low heart rate training coincides with my nutritional changes via the Primal Diet (read about my 1st 25 days on the low carb Primal Diet). I actually started following the Maffetone Method a few days before the Primal Diet, so I was able to really see how the low carb Primal Diet affected my body on runs. For 30 days I have run with my heart rate at or under 149 BPM. I track it constantly with my Apple Watch (read my Apple Watch reviews), and any time it hits 150, I walk or slow jog till it drops a few beats. During these 30 days I have run 160 miles. These have been 160 very slow miles, much slower than I am used to running. The experience has brought me to the harsh realization that, despite running thousands of miles, 3 marathons and countless long runs over the last 2 years, my aerobic fitness is vastly underdeveloped for someone who runs this much. I apparently spent way too much time training in the dead-zone where my heart rate was too high to build aerobic endurance but too low to get solid anaerobic workouts. Running like that everyday led to overtraining and declines in my running performance. It also aided in my weight gain last year, largely because of the unhealthy cycle of always carb loading before and after workouts and never really burning any fat during all that running.

So with the Maffetone Method, I hope to take a step back and reboot my long-term fitness training as I also focus on long-term dietary changes and natural, healthy eating. Since I am a month into Maffetone Method low heart rate running, I need to keep running slow on every single workout for at least another 1-2 months before I start adding in any tempo runs or speed workouts again. As someone who has had some success at local road racing the last couple years, always finishing in the top 10 overall and top 1-2 for my age group in any race under 10 miles, it is difficult to keep my focus only on running slow and easy and never testing myself with speed sessions or even just running the last mile hard to end a workout. I am trying to keep perspective that a few months of slow running can ultimately help me run faster and further with less injuries, but meanwhile I have this fear that I will lose all the speed that I worked so hard to attain.


Last year before I gained 20+ lbs I was running many of my miles in the 7:00-8:00 range, with some miles under 7:00 and some slower. I rarely ran over 9:00/mile. After I moved from Indiana to Alabama, gained weight and struggled with the heat, humidity and hills here, I was running many of my miles in the 8:30-9:30 range, sometimes faster and sometimes slower. Earlier this year before I started using the Maffetone Method, I was starting to bring some of those times back down. My best half-marathon distance run this spring/winter was at 8:25 pace (1:50:31), still a full 10 minutes slower than I ran the distance a year ago, but I was showing signs of getting faster again. A week before I started the Maffetone Method, I ran a couple of 10-11 mile runs in the 8:40-8:50/mile range. It has been quite awhile since I ran a significant distance at a sub-8:00 pace. The big problem is that I still had not been losing excess body fat, and I knew that without dropping weight I would never again PR at any distance.

With low heart rate training, my paces slowed significantly. My very 1st Maffetone Method run was 11 miles at 10:20/mile. The first few runs were around this range, and then I added the Primal Diet. When I cut carbs, my running immediately got even slower.

My next few double digit runs went like this…

11 miles at 10:49/mile

11 miles at 11:11/mile

10 miles at 11:54/mile

My shorter runs were also falling in the 10:30-12:00/mile range. While carbs were mostly non-existant in my diet, my body was struggling. Everytime I ran over 6 miles, I ran out of energy and really dragged the last few miles. I also have experimented with running in fasted states, completing workouts with no food for the last 16-24 hours. The purpose of this was not to further torture myself, although it was torture, but it is part of the process of training my body to burn fat for fuel instead of relying too heavily on carbs during runs. It also helps to shed some pounds.


One thing I have really liked about this whole low carb, low heart rate transition is that it has opened my eyes to how different things affect my heart rate, therefore affecting the way I feel and perform during runs. Temperature is a major factor, as my heart rate seems to jump several BPM at the same pace on the same terrain when the temperature goes up from the low 60ºs to 75º+. When the temperature reached 83º (feels like 87º) this week, my walking increased and pace slowed significantly. I was running on a hot, sunny day a few days ago, and while running the same pace, my heart rate would almost instantly jump from 145 bpm to over 150 bpm just by moving from shadowy areas to direct sunlight for a couple hundred yards.

Comparing fasted-state runs to runs after breakfast, it was pretty clear that food and hunger also have a strong impact on my heart rate and running performance.

Sleep is another major factor, and my workouts went significantly better after 8-9 hours of sleep than after 5-6 hours of sleep.


 After 3 weeks of the Primal Diet and almost 4 weeks of running with the Maffetone Method, I suddenly had a major breakthrough. The conditions all lined up perfectly. The temperature dropped to the high 50ºs/low 60ºs for a few days. The carb cravings were finally dissipating. I got decent sleep for a few days. My overall energy levels were rising. Things were starting to feel really good for a breakthrough week.

The breakthrough did not come on Monday as I ran 6.3 miles at 11:15/mile. Tuesday of last week is when the temperature really dropped, and I ran 5.25 miles at 10:11/mile, over a minute per mile faster than the day before! Then Wednesday I ran twice as far, but even faster, running 10 miles at 10:02/mile.

The next day on Thursday I ran 10 miles again, this time at 9:42/mile! Compared to my old paces, this is still slow, but just a week earlier I ran 10 miles at only 11:54/mile. In just a week my pace increased over 2 minutes per mile at the same heart rate on the same running terrain. That is incredible! The weather was a major factor, as was my sleep and diet, but obviously I was starting to show signs of some increased aerobic fitness too.

Last weekend I ran a pair of 7 milers, also in the high 9/low 10 pace range, before the temperature shot way up again this week, slowing my pace significantly again the last few days.


Most of my runs the last 2 years were progressive runs, meaning I would start at a slower pace and gradually run a little bit faster each mile, kicking as hard as I can down the final stretch of my run. I noticed a distinct reversal in this pattern when I started running with the Maffetone Method and cutting carbs with the Primal Diet. On almost every single run the last few weeks, my first mile was the fastest, and I got progressively slower each mile until I finally stop.

The exception to this reversal occurred last week during my breakthrough week. On those breakthrough runs, I would start off around 10:00/mile or just under. Then I would run 9:40, then 9:30, then 9:10, and finally I got 1 single mile in the last month under 9:00. I was getting progressively faster again for the first several miles. Then my pace would slow once again around mile 6, but rather than dropping drastically every mile after that, I would actually hold a slower, but steady pace around 10:15-10:30/mile for those final miles.

As the hot summer arrives in Alabama, I know that most of my runs the next few months will be a struggle, and it will be hard to keep my heart rate down in the heat, leading to more walking and slower paces than I would prefer. But last week I got a glimpse of how this can pay off in a few months. Enduring the summer heat and humidity, along with continuing to build a strong aerobic base could lead to major gains once the temperature drops next fall and winter, especially once I get to a point where I can add speed work again.


Psychologically I needed that breakthrough last week to keep my motivated and to build my confidence in this whole process. It reminded me that running this slow does not have to last forever, and if I stick with it my paces will come back down eventually. In a few months with a stronger aerobic base, lower body fat level, freedom from carb dependencies and some time to recover from the effects of overtraining, I will be in position to hopefully taking my running to another level, this time doing things the smart, healthy way.

Click here to read my follow-up post “Stationary Bike and the Maffetone Method”