Here are some of my answers to frequently asked questions for low heart rate training, generally pertinent to Maffetone's approach.
Disclaimer: read at your own risk. Author is not responsible for any health conditions, reduction in performance, injuries, death, or humiliation that results from reading or following this advice. For professional advice, see a physician and get a coach.
1. What might indicate that I could really use some low heart rate training?
You have poor aerobic fitness, which doesn’t necessarily mean that you aren’t a good or a fast runner. You can be running 2:45 marathons and have poor aerobic fitness (which means perhaps you're capable of 2:15 or faster marathons and hence you can probably run a 5k in about 14 minutes). Maybe you run a 20 minute 5k, but a 4 hour marathon. Here are some possible indicators:
a. There is no pace “relationship” between your shorter distance races and your longer distance ones. What does this mean? There’s a good explanation in Hadd’s article below, but there are some rules of thumb to the effect that, if you assume you are properly trained for the distances you are racing, your pace will decrease by the same amount, each time you double the distance of your race, usually somewhere between 12 and 16 seconds, depending probably on genetics. Therefore, on the lower end, one who runs 5 miles at an 8 min/mi pace would run 10 miles at 8:16/mile, and 20 miles at 8:32/mile. The relationship may degrade some, particularly as the distances get longer in between (say 5k to marathon, or even half to marathon), but you should still see a relationship. If the math is getting too messy for you, you can use a common pace calculator, such as that at McMillan Running and see whether your short distance times project out to long distances. If your marathon is more than 20 minutes slower than what your half predicts, then there’s a good chance you have an aerobic problem, assuming (1) you completed a full training program for the marathon and (2) the marathon was not in abnormally high heat and/or humidity or had other significant environmental factors.
b. You are incapable of running at low heart rates, for example, you find you have to walk at a heart rate of 180-your age.
c. You always burn out somewhere between mile 16 and 22 in a marathon, no matter how much carbohydrate you take in.
d. You have difficulty completing your long training runs and your pace slows down in the last several miles, just in order to finish them.
e. You are completely shot at the end of your long training runs, or even your short runs. (You probably will be after most forms of speed work, that’s expected, to a degree).
f. You are sore most of the time and possibly plagued by minor injuries frequently, or you get sick quite often.
g. Your race times are not improving – it seems as though you are working harder and harder in training and nothing’s getting better.
h. You are very reliant on carbohydrates to get you through training runs.
2. What are some of the relevant websites?
Mark Allen on Ironman Live
Mark Allen - duathlon.com
Pfitzinger on basebuilding
Pfitzinger on fat utilization
3. What benefits might I reap from low HR training?
a. You’ll train your body to use fat for fuel at a reasonably fast running pace (reasonably fast means different things to different people). With enough of this training, this means that you can preserve your precious carbohydrate stores throughout very long races. You can avoid “the wall” and “bonking” in marathons and longer races.
b. Running at a much lower level of effort, aerobically, will be much less taxing on your body, even if you end up as fast as or faster than your original training pace.
c. You will strengthen your legs and hips tremendously.
d. You will be adding an additional fuel tank that you didn’t realize that you had.
e. You will develop significant aerobic speed, which means you may reach speeds that you were doing before low HR training at very high level of effort, with ease.
f. You will eliminate as strong of a reliance on carbs during most races, and certainly training runs.
4. Scientifically, what is happening with this approach?
You are training your aerobic system, which includes using more fat (vs carbohydrate) for fuel and using slow-twitch muscle fibers as well as building mitochondria.
5. Will this make me a faster runner?
It may not make you faster, but it will help you build aerobic speed, converting much of the capability of your anaerobic system to your aerobic system. Since your anaerobic system cannot sustain you for very long, this means that you will be able to sustain higher speeds for longer periods of time.
6. How many miles per week do I need to do? Can I obtain success at very low mileage?
There’s no set answer and it all depends on your goals – what distances of races you want to do, etc. The more aerobic volume you do, likely the faster and more significant progress you will see. There is some question as to what kind of progress you can make on only 10-15 miles per week. However, at that volume, you may be better off just taking it easy on most of your runs, rather than following a strict heart rate regimen. This type of mileage is not enough to support speed work nor to gain optimal race performance, so pace capability should not be an issue. If you are just trying to solve some of the other problems about fatigue and pains mentioned above, you can probably just find a heart rate 10 or 15 beats above MAF and stick with that for a while. (MAF stands for "maximum aerobic function" and it is defined in the Maffetone and Mark Allen articles. It is similar to "aerobic threshold" although there are many ambiguous definitions for aerobic threshold. It is not dependent on maximum heart rate.) If you are just doing low mileage because “your body can’t take it,” following this method carefully should enable you to increase your mileage.
7. Do I have to control my heart rate in other activities, such as biking and swimming? How about in my spin class or weekly swim interval session?
Yes, you have to stay under the MAF heart rate for all activities, which certainly can be difficult, if not impossible in spin class, master’s swim class, etc.
8. Is age a factor in low HR training?
Yes, in many ways. The MAF heart rate is a function of age and it makes the 1 beat/year decay assumption as in the age-predicted max heart rate formula (which is all but worthless). However, more importantly, it seems as though runners under 25 or over about 55 may either have not been a significant sample or may not have seen the same type of progress during Maffetone’s testing as those in that range. Nonetheless, there have been many successful cases outside of the 25-55 range.
9. Can I mix a race in once or twice per week?
No, you shouldn’t during the basebuilding period. Any racing will interfere with and possibly set back progress. Wait until basebuilding is complete first.
10. What kind of progress might a “real” person see?
The attached "photos" show a “real” person’s progress in MAF training pace (mine).
11. At what distance races will this form of training help to make drastic improvements in?
The most significant improvements will be seen in races that will bring people with poor aerobic fitness to glycogen depletion, such as the marathon and longer and the half ironman and longer. This may make the difference between a 3:50 marathon within an ironman and a 6:30-7:00 26.2 mile death march, as an example.
12. If I take medications, stimulants, etc., that raise my heart rate, do I reset my MAF value to a higher heart rate?
No, and in fact, Maffetone says you should target a lower heart rate if you are on medications.
13. Do I reset to a higher heart rate to account for illness or significant heat and humidity?
No, you always need to stay under no matter what is causing the rise.
14. My max heart rate is very high – should I use a higher MAF heart rate?
No, not unless your max is over 300. Why? Because there can be a lot of heart beats between your anaerobic threshold (the point where you become fully anaerobic) and your maximum heart rate, none of which will give you much to work with for endurance.
15. My max heart rate is very low – should I use a lower MAF heart rate?
Quite possibly. It’s always safer to stay on the low end. If you know that you have a very low max heart rate, I'd recommend you take a look at the Hadd article,
section 6, to select a low heart rate target.
16. How many beats do I let my heart rate climb when I go up steep hills?
None – you need to stay strictly under. This means that in the early stages you may have to walk even gentle hills or you may want to stay on the treadmill until you build your conditioning. Or you may want to experiment with how you can slow yourself down and control heart rate up hills.
17. How could this be better than something more personalized, such as %max heart rate?
In many cases, the numbers will be similar, but % max heart rate doesn’t take fitness into account at all, whereas this method does, and furthermore, for those with high max heart rates but low to moderate fitness, the anaerobic threshold will most likely occur at lower heart rates than those with high fitness and low max heart rates (at a given age).
18. Is this the same as running at x% of heart rate reserve or of max heart rate?
Since max heart rate doesn’t account for fitness, it is not the same. It is somewhat the opposite from using heart rate reserve (HRR) because an HRR approach will have someone running at a higher heart rate if he/she were ill or less well-conditioned (with higher resting heart rate), while this approach does the opposite. Also, for many people the HRR lower limit will be at a heart rate high enough to where more of the anaerobic than the aerobic system is used.
19. Do I need to eat “low carb” to be successful at this? Is this a promotion of “low carb” eating?
No to both. The key is to avoid carbs prior to training runs or races. Better results may be obtained by avoiding carbs during training runs, but there’s no solid evidence.
20. Will I get slower at short races by doing this?
Initially, in the first few weeks, while you are transferring your speed from your anaerobic system to your aerobic, you may slow down. Ultimately, you should get faster at every race that uses the aerobic system, from the 400 or 800 higher. You may get slower at anaerobic races such as the 100, but after the base is built, you can get back to speed work for the anaerobic system and you will be much better prepared.
21. I’ve been running all of my runs at 75% max heart rate and I’m seeing no progress. Doesn’t that mean that this approach doesn’t work for me?
This approach does not involve running at 75% max heart rate. It might for some individuals, but for most, it will be much, much less than that. For most people, 75% HRMax will be right in between the anaerobic and aerobic systems.
22. Is there any way to use this approach with a more personalized formula for me?
Yes, but it may be costly and burdensome and you may not get a better bottom line training zone. You can have a vo2max test done, find the heart rate where your RQ (or RER) value is 0.78, which corresponds to 25% carb burn/75% fat burn and use that as your max training zone. Or you can use 80% of your anaerobic threshold heart rate. These should be close to the MAF values.
23. Is there any way to follow this approach in a simple way?
Yes. Do all of your running and other activities strictly below MAF, never letting it go above, for at least 12 weeks. Do not take in carbohydrates within the three hours prior to your run. Avoid significant weightlifting. That’s it.
24. What kind of running schedule do I need to follow?
This is not a “running schedule” program. That’s based on your goals, mostly what races you want to run. However, it seems as though individuals who run the same distance runs every week do not see the progress that those who change things around, add longer runs, etc.
25. I have not made any progress – what’s wrong?
First, make sure you have given it enough time. You may see no results for even 8 or 12 weeks for the first time, depending on your running history. Next, make sure you are following all of the rules, including staying under MAF for everything you are doing, including swimming, biking, etc. Those with exceptionally poor aerobic conditioning may have to use an even lower heart rate. Last, but not least, make sure you are getting some downhill running in where you have to speed up to keep your heart rate up at MAF and sustain it for more than a few seconds. This will help you maintain leg turnover and improve running economy. You're unlikely to see much improvement if you always run the same pace.
26. I was making progress, but I am no longer progressing, so what do I do now?
Consider how long you have been at it and what kind of aerobic problems you had before starting. It’s possible that you’ve done all you can for now and the next step is to add some speed workouts as a small percentage of overall volume. Also, be sure you are tracking everything, including temperature, humidity, and hills, and that they are not varying, causing you to slow down. Lastly, be sure you are getting in some good periods of downhill running at a higher pace at the MAF heart rate. Any testing you do on a periodic basis should be in virtually the same conditions, such as on a treadmill in the same gym where the temp and humidity are well-controlled. If you've already spent a good 12 weeks at it and you've peaked out, then it's time to start adding speed work in small quantities. See Mark Allen's recommendaions for an approach. Personally, I like the "fast-finish" long run as McMillan suggests for a first step.
27. What should I do if I have to walk 90% of the time to keep my heart rate below MAF?
First, make sure you have actually given the slower running “ the college try.” If you say you cannot run slower than a 10 minute mile, I don’t believe you. If someone who runs a 5:30 mile can “run” a 17 minute mile, then anything’s possible. With that said, you probably need to either just run for a while and not worry about heart rate, or add 10 points for a while and see if your heart rate will eventually come down. This process will take much longer. This is a sign that you have basically no aerobic fitness.
28. I have a new type of soreness after doing this for a couple of weeks. Is something wrong?
No, this is natural. The initial slow down will be effectively a new form of cross-training. After a couple of weeks your body will get used to it and shortly thereafter your pace will start to improve.
29. Is this going to make me slower overall and break down my stride, doing permanent damage?
No, just 8-12 weeks of running at a slower pace will not damage your running forever. However, if there is no progress after 6-8 weeks whatsoever, you need to start analyzing what’s going on.
30. I like to lift weights – do I need to stop?
Weightlifting is anaerobic, so in theory it can interfere. I kept up my upper body weightlifting, with somewhat heavy weights and still saw great progress. Lower body may be more of a problem.
31. What about the popular statement “run slowly and you will become a slow runner”?
Well, if you always run the same slow pace, you will probably always run the same slow pace. The first element of this approach is basebuilding – getting running in using the most of your aerobic system and hence developing fitness in your aerobic system. The second is increasing pace at the low heart rates as your body allows. After a few weeks, your pace should steadily start increasing at the low heart rates and you may eventually be running at faster training pace than you were beforehand.
32. I am 17 years old and this sounds appealing to me – what’s your advice?
There’s a big question as to whether this low heart rate stuff is really relevant to someone under 18 or so, at least with regard to the heart rate formulas. My suggestion would be to just run easy pace basebuilding in the offseason without concern about specific heart rates. Just take it easy and don’t be driven by having to run at some minimum pace, nor should you go home and analyze your pace performance after your training runs.
33. Does this contradict the advice of many of the renown coaches and physiologists, such as Pfitzinger, Lydiard, Daniels, McMillan, Hal Higdon, etc?
Some elements might, but for the most part, this training will prepare you well to start any of their programs because many assume you already have a strong aerobic base before starting.
34. Won't the slowing down and lack of speedwork for a while erode my VO2Max?
On the contrary, it will increase your VO2Max. As it will your anaerobic threshold. My vo2max went from 54.3 to 62.5 over my 5 month period of strictly low heart rate running with no speed work. Nonetheless, you need not be too fixated with VO2Max for marathon performance. It's not a great predictor if you don't have the strong aerobic base to go with it.
35. When do I know that it's time to start into my race-specific training program with "quality workouts"?
You'll know when you don't have to ask. Either you have built the capability to run well at low heart rates and you are no longer making progress or you have run out of time and you need to jump into, for example, your 18 week marathon program. It is quite possible that in your first time doing this, you will plan to jump into a "quality phase" after 3 months or so at some specified time before your race, but you'll see such good progress using low HR training alone that you'll just want to keep it up until race day. If you keep it up season after season, year after year, eventually you won't likely improve further without some form of speed work. However, many runners can be competitive (to the extent of qualifying for the Boston Marathon, the Western States Endurance Run, the Hawaii Ironman, etc.) just doing low heart rate training, running the periodic races, and very minimal speedwork. There's little doubt that eventually to compete with the elites in marathon and shorter, low heart rate alone will not be sufficient.
36. Aren't these just junk miles that you are saying to run?
Junk miles are really miles that have little training value - not high enough for any tempo, speed, or "interval/recovery" value, and not low enough for aerobic value - somewhere right in between the aerobic and anaerobic systems. (Really, it's hard to say that any miles are junk miles.) This element of an overall training program is focusing on the aerobic system and the more mileage you put in, the stronger the base you build, and the faster you get at low levels of effort. This will amount to better race times than you had before and bigger smiles late in the race, especially at the end. We all like that.
37. Once I've built a strong aerobic base, am I done?
Sure, as long as you don't race. Once you go through a number of races for the season, you will wither away your aerobic base, which is fine and expected. In the off-season, after your recovery, you start to rebuild. Each time you do, your buildup should be shorter and your base should become stronger.
38. Which formula should I use for MAF? Should I try to be as high or as low as possible?
You should be as conservative (low) as possible, especially for your first few times doing this type of basebuilding. After several times, your body will become trained to burn fat at higher heart rates and you can move up a notch. For me, when I tried to stay 5 beats below MAF, I saw better and faster progress.
39. My heart rate rises during runs, especially long runs - how much should I let it rise?
Everyone's heart rate will rise during a run due primarily to the body's heating and dehydration. Properly rehydrating will reduce the amount of heart rate drift you see, but you cannot eliminate it. In order to stop it from rising, you have to reduce your speed, so you either need to start at a low enough heart rate such that it doesn't drift above your MAF by the end or you need to slow down your pace with each subsequent mile as needed. As your aerobic conditioning develops, you will notice that your heart rate drift rate will reduce, but it will never go away.
40. Will this help train me to reduce my dependence on electrolytes or fluids during runs?
Absolutely not. In fact, it will train you more to understand your requirements for fluids in your runs. Electrolytes are more complex. This will help you learn your body's running better than you have ever known.
41. During my last long run, I could not keep my heart rate under control for the last 5 miles, I was about 10 beats over most of the time. Have I sabotaged all of the aerobic work I have done?
This will happen, especially in the early stages and your first few runs of 15 miles or more. Forget about it and move on - it's not going to do any significant damage to your training and next time it will get easier.
42. Isn't this basically Lydiard's basebuilding approach? Do I really need to use a heart rate monitor and adhere to all of these rules?
This can be an approach for Lydiard's basebuilding. Many people certainly don't need a heart rate monitor to do this, but without one, it's very difficult to identify how low the level of effort has to be in order to maximize the use of the aerobic system while maintaining some kind of running speed. As Hadd states in his article, many people have drastically different interpretations of what "easy" means. Perceived level of effort and talk tests do not always ensure that one is using mostly the aerobic system, especially for those who have very poor aerobic fitness. Some people stay very much in the aerobic regime naturally, particularly after several years of running. Others spend too much time at too high of a level of effort, and either get injured or hit a roadblock on performance improvement.
43. I have a high heart rate. My pace is too slow at the MAF heart rate. Is it ok if I run at 15-20 beats higher?
Sure. Of course you're always welcome to run however you want. But you won't develop your aerobic system or see any of the progress described within these articles. If your heart rate is very high when you run at what you consider an easy pace, it means you have poor aerobic fitness. The slower you are at the low heart rates, the poorer your aerobic fitness, and the more you need it. Insult to injury? Maybe.
44. Are you saying that this approach alone is superior to that of most or all of the respected coaches and physiologists?
Not at all. This will give you the preparation and build your endurance that will make a more aggressive training program much more effective.
45. Will this approach all but assure me that I'll be winning races or compete with elites?
The only thing that it will ensure you is that if you currently have times that fall off significantly when the distances get longer, if you stick with it for long enough and don't cheat, you will get faster at long distances. It's all relative to what you were able to do before and it says very little about how you compare with others. If you want to win races and compete with elites, this will be a good pre-season preparation. After that point you'll have to work hard and if you're running the marathon, you'll need to learn how to run as close to your lactate threshold for as long as you possibly can without boiling over. Combine that ability with 4 minute mile speed and you'll be winning a lot of races!
46. Can I do speedwork with this approach?
If you are in the basebuilding phase, most forms of speedwork are likely to interere with or set back progress, particularly if you have a poor aerobic base to start. However, one form you can do is downhill running (still keeping heart rate below MAF). Carefully. If you're not used to downhill running, you need to ease into it, a little bit at a time. Focus on short strides, fast turnover. Don't just let yourself go, nor should you be fighting gravity to try to slow down. Either of these will put a lot of pounding on your quads and could make you susceptible to knee and hip injuries. Some treadmills also have negative incline settings, which can allow you to run at a faster pace while still below the MAF heart rate.
47. How would you describe the first few weeks of doing this?
Miserable. Unbearable. Painful. An exercise in futility. An exercise in patience. Pride-depleting. Although there are a few who find the slow-down refreshing. Most will be miserable at first.
48. I've got a race coming up in 6 weeks. If I start doing this will that be enough time to give me a good improvement in time?
Most likely not. Six weeks is not likely enough for any significant improvement. The best time to start training like this is in the off-season, when you've got at least several months until your next race and when you won't be tempted to sneak in a race right in the middle.
49. Is low heart rate training just preparing for running races at low heart rates?
Absolutely not. You can condition yourself to run fast at low heart rates, which will enable you to run very fast at higher heart rates. On the one hand, you can do all of your training at low heart rates and you will still be able to sustain much higher heart rates during short and long races much better than you did before. However, if you want to do your absolute best and reach your ultimate performance capability, you'll have to add more aggressive workouts to your training after you've built your base. But, you will be much better prepared for them and more capable to run them at much higher paces with a developed aerobic system.
50. Will running all runs below MAF make everyone faster?
No. Someone who already has a very well-developed aerobic system will
most likely have to do more intense running to get faster.
51. What kind of pace can I expect to run in races for a given pace
I'm capable of below MAF?
Combining Maffetone's pace table and McMillan's pace calculator and
making the following assumptions: (1) MAF pace is calculated for
a relatively flat area at least several miles into a run, (2) conditions and
running environment (hills, wind, temperature, humidity, etc.) are
comparable between MAF test and the race, (3) you are well-conditioned
aerobically (otherwise, the 5k prediction may be good, but the others
MAF 5K 5K HM marathon
min/mile race pace time time time
10:00 7:30 23:18 1:48 3:47
9:00 7:00 21:45 1:41 3:32
8:30 6:45 20:58 1:37 3:24
8:00 6:30 20:12 1:33 3:17
7:30 6:00 18:38 1:26 3:02
7:00 5:30 17:05 1:19 2:47
6:30 5:15 16:19 1:16 2:39
6:00 5:00 15:32 1:12 2:31
5:45 4:45 14:45 1:08 2:24
5:30 4:30 13:59 1:05 2:16
5:15 4:20 13:28 1:02 2:11
5:00 4:15 13:12 1:01 2:09
52. What are your qualifications for this? Where do you get your information from?
I am only qualified in that I have gone through this type of training "half-way" (which didn't work out well) and I've done it in a dedicated fashion for over about 2 years now and I've seen remarkable results: improvement in marathon time by just about an hour, improvement in 50 mile race time by over 2 hours, and improvement in 10k race time by over 6 minutes, just by establishing a strong aerobic base and with no speed work. Simply put, I fixed an endurance problem I had, just as many runners have. I'm just a regular guy and this has helped me move from middle of the pack to the top 10 or 20% in many races. I've just pulled information from most of the websites above, "Training for Endurance" by Phil Maffetone, "Slow Burn" by Stu Mittleman and through discussions with many others that have gone through this form of training and have contributed to this list.
53. When do I add speedwork?
Ah, yes, one of the most common questions. Too bad there's not a simple answer. After much pondering over this, I would say the optimal time to add speed work is the point at which you have to really push to keep your heart rate up at the MAF level. That's a sign that either your aerobic system has surpassed your speed and strength or that you may be getting complacent.
54. Is there a short synopsis you can provide?
Yes. Make sure you have a reason for doing it. Some are given above in #1. Give yourself a good 12 weeks or more running strictly below the MAF value as defined in Maffetone or Mark Allen's articles (180-age +/- 5 or 10). Do not let it go over on hills or in adverse environments. Get in a good percentage of your mileage, at least 10% or so, on downhills and be sure to pick up your pace to keep your heart rate up at the MAF value. It doesn't so much matter what the average pace of your training runs is or how slow you have to go at times, but you should be getting some time in at higher paces. If you are in your low 20s or over 50 or 55, you may have to make some adjustments.
Above all, keep it simple. If you make things too complex or question things too much, you will just drive yourself crazy. Expect a lot of frustration when first trying this and swallow your pride. A good majority of people quit early on using this approach because of how slowly they have to go. Think of this as a diet. If you periodically cheat, depending on how much, you may deter your progress. Those who need it the most will have the hardest time and the most frustration. Once you binge (i.e., start racing), you will lose a lot of what you built up and when you finish racing, you'll have to do it again, but some of it will stick with you from last time and you will be wiser this time around. The main difference is that you're dieting in preparation for a binge. Just make sure you save your binge for the races, not the training course.