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Aerobic endurance is something I’ve discussed on the sock-doc site many times. Its importance in both fitness and health is often underestimated either because there are news reports citing studies saying too much will harm your health, or athletes neglect the time and effort to put in the training to build the aerobic system and see its huge value. Aerobic, as you perhaps know from reading other Sock Doc articles, does not mean “chronic cardio” nor does it mean you’re necessarily walking for hours to develop “slow” aerobic fitness.
Developing aerobic endurance means that you’re training your body to sustain some level of activity for a prolonged period of time, (typically 30 minutes if not much more), and you’re utilizing fat as a fuel source rather than glucose (sugar) or some other energy source. Developing such a system takes time – just like any other fitness aspect including strength and speed. One big difference with building the aerobic system is that, based off my experience, people are impatient and inconsistent – they want results faster than they typically come and they don’t want to put in the time.
Your Aerobic System Sucks
Most athletes are training too hard too often. High intensity workouts and of course training anaerobically (“chronic cardio” as so many “anti-aerobic” pundits yap about) too often is a sure way to not only not develop your aerobic system, but end up sick, injured, or yeah even dead.
If you want to hike, paddle, run, cycle, swim, or do whatever exercise faster for a longer period of time then you want to develop your aerobic system. It doesn’t mean that you never train anaerobically (HIIT workouts) ever again, just temporarily. For most people this means you have to slow down and realize that your aerobic system sucks. Yes – that’s right – your aerobic system probably sucks and you don’t even know it; realizing this is the first step to correcting the problem so you can deal with it.
Aerobic Endurance Success
Several months ago I got an email from a patient who I helped a couple years ago with an injury. Amanda, well known in the running community and blog-world as Miss Zippy, had recently suffered through another crummy marathon. (She has given me permission to share her story here.) She bonked way early into the race, though her training, she thought, was fine. She had put in the work. We talked for some time on the phone and at one point she revealed to me that she wasn’t training with a heart rate monitor. She was training based off miles and intensity/exertion. I, of course, preach training for time and heart rate most all the time.
So I put it to Amanda rather candidly as I always do. She was looking to set a PR yet she was only getting slower and time was slipping by. If she kept doing what she was doing she’d never run a marathon PR let alone a half-decent race. “What do you have to lose?” I asked her. And so she listened.
Starting in May, Amanda trained aerobically 100% of the time. That meant no speed work, no racing, and no hard hills. She also changed her diet to more fat and less sugar to fuel the aerobic system. Every month she did an aerobic fitness test to gauge her improvement. The times below are Amanda’s mile splits over four miles at her aerobic training zone heart rate. This means that she kept her heart rate in a very narrow aerobic zone for the four miles (after a warm-up). So her intensity (input/exertion) was the same every time. There are some dramatic changes as you can see, and maybe some you cannot so easily realize.
In May you can see that not only was she barely able to run a sub-10 minute mile for just two miles, but the difference between mile one and mile four was almost one whole minute! This is what people refer to as cardiac drift, which I will discuss in a bit.
In June, just one month after focusing on her aerobic system she was already reaping the benefits. Mile one and two are the same time and even her third and fourth are close, with a much less cardiac drift.
Fast forward to August and wow! Miss Zippy has taken well over one minute off her first mile and two off her fourth. She’s now running four miles close to seven minutes faster than just a few months ago – at the same intensity! Not only that, August was a lot more hot and humid than May so theoretically she could have run even faster in a cooler environment. Pretty awesome.
May: 9:37, 9:51, 10:23, 10:31
June: 8:55, 8:55, 9:07, 9:04
July: 8:48, 8:40, 8:55, 9:00
August: 8:20, 8:15, 8:24, 8:32
Is Speedwork Essential for Racing?
A few weeks ago Amanda contacted me with a very common question, which I slightly edited for clarity and consistency with this article.
“So I’m weighing how long I’m going to do aerobic training and/or how to transition to some speedwork training. I was initially planning on 16 weeks of it, which would bring me to mid-Sept. I wanted your opinion: at this stage in the game, would I potentially hit a good marathon by just continuing into Nov. on strictly aerobic (race is Nov. 16)? Or should I do aerobic for all but one or two workouts per week starting in Sept and get some specific race pace work in? I’ll be honest—I am starting to miss running with my friends after all this time!”
I made Amanda wait for her answer as part of this article so here it is.
“Why mess with a good thing. You’re seeing huge improvements in your aerobic conditioning and your SPEED. You don’t need speedwork right now to get faster because you’re getting significantly faster without it. You have just about ten weeks before the marathon. Let’s see where your September aerobic times are. If they’re still coming down and/or the first and forth are less of a gap, then you continue another few weeks with the aerobic training. If you eventually don’t see the improvements, whether September or October, then you can stick in some speed work training. You might not hit an aerobic plateau until sometime over the winter, and then at that time you can put in a good four to five weeks of anaerobic intervals. But for now, stick with what’s working. What’s going to happen if not already is you’re going to be running, perhaps down a slight incline, only to look at your HR monitor and think ‘damn – I have to run faster’, so you’ll need to pick up the speed; you can do some aerobic intervals at that time and work on faster leg turnover.”
I hope you listen Amanda!
Cardiac Drift
Cardiac drift is basically when your heart rate increases after ten or so minutes of exercise with no change in workload in response to arterial pressure and stroke volume. So at the same workload your heart rate “drifts” higher to some degree. The main reason behind the drift is to promote cooling, as the main factor influencing cardiac drift is hydration, ambient temperature, and of course – good ol’ fitness. The more fit you are the more efficient your body is at any given workload and the less you will need to cool down (this is why you sweat more when you train harder).
So how much of a cardiac drift is normal? That’s hard to say. Some drift is normal but too much drift – like Amanda had in the May – is definitely not normal. Personally, I still think she is still having too much cardiac drift, though the August temperature could have been a factor. Some may disagree. Personally, I can run at an aerobic zone heart rate for four miles and keep my heart rate within just a few beats (in a not crazy hot/humid environment).
I have read that some people think that due to the cardiac drift, you need to increase your intensity a bit since your heart rate is naturally increasing without any change in workload and oxygen consumption. So if you slow down to keep the heart rate in “the zone”, you’ll essentially be training slower the longer you exercise.
I don’t agree with this for two reasons. First, as mentioned, I’ve always seen cardiac drift to be an issue with unconditioned athletes, at least to any measurable HR variance. In other words, once you develop aerobic conditioning, you don’t have the drift much at all. Second is that some of the cardiac drift is associated with electrolyte and glucose imbalances. Actually in one study the researchers were able to practically eliminate cardiac drift by giving the athletes a glucose and hydration drip. So the longer you exercise at a higher intensity, the more glucose and electrolytes you will deplete. That is not a reason to push your heart rate up – it’s a reason to keep it down.
Slow Down to Speed Up
As the line above here says – do just that. Slow down and you will soon speed up. If you aren’t training with a heart rate monitor then you have absolutely no idea of your exertion rate. Sure you can get away with it for a while, but if you want to train/race longer at a faster pace then there’s no reason not to have a monitor. You may have to walk for a while, maybe months (not at once!); you may have to crawl. But you’ve got to start somewhere and most athletes out there are way more unfit than they want to believe. So accept it and change it now rather than later. Give it time and it will pay back in big rewards.
Dr. Stephen Gangemi "Sock Doc"
I'm a board-certified chiropractic physician and clinical nutritionist with a passion for true natural health care. I implement dietary & nutritional therapies, exercise & movement practices, and lifestyle changes along with manual therapy techniques to help the body heal and prevent illness and injuries.
Scott Kummer says
Great article! I am amazed by the number of people that only believe in “straining.”
Sean says
At what point would you expect cardiac drift in a given workout? I.e. you say above you can run 4 miles and have almost no change in pace at the same HR. What about 10? Or 15? Or 20?
Sock Doc says
It all depends on conditioning, environment, and nutrition. I’d say there is no “normal” or “common” here.
misszippy says
In my case, the longer I go, the more the drift. Saturday’s 18 in high heat/humidity was nearly impossible at the end!
Drew Cummings says
Miss Zippy, would that coincide, as Sock Doc says, with glucose and electrolyte depletion?
Sol says
Wonderful article. Thank you. Can you tell us what Amanda’s training schedule was? How long were her runs (timewise) and which days of the week did she run?
Thanks.
Sock Doc says
I can’t provide that. She can here if she chooses to.
misszippy says
Hi Sol–basically running 6 days/week and started MAF around 40ish miles/week. Now around 50 as I head closer to marathon.
misszippy says
As you know, I don’t like your answer! Debating, debating. But I will admit you have yet to steer me wrong.
Steve P says
I found the Maffetone program back in 2004 and have followed the system religiously since then. This has worked well for Ultraracing, but i have to imagine we need some faster running to help the legs when running faster.
For instance, although I have trained in my MAF zone of 115-125 (I’m 61), I still need to interject walking to keep my HR below 125…and this is at an average pace of 11-12 mpm, generally averaging 50 mpw. I never got faster doing this training, but enjoy it…if anything, I’ve gotten slower. I was a sub 2:50 marathoner just 30 year ago.
Is it possible that this protocol just doesn’t work for some runners? I love it for the injury prevention and freshness I feel during most runs, but why do most coaches have their runners doing speed or hills?
Sock Doc says
Correct it’s not for everyone. This is why I note lactate testing is ideal.
Steve P says
Do you have an article on lactate testing?
I have done a max HR self test (i do this every year) and I find i’m more comfortable at around 70-75% of max. This still feels easy, breathing rate is low and I feel fresh the next day.
I do agree that 90% of runners train much too hard on most days and a 6 month stint of Maffetone can only help…then do a lactate or max HR test to find your real numbers.
Thanks…
Sock Doc says
That’ll be in the book, not here.
Steve P says
You have a book? Or is one coming? 🙂
Sock Doc says
Hopefully early Spring 2014.
Dave says
This is a super real life example of how to build out the aerobic system the right way! Burning fat instead of running through glycogen. To link a previous article of yours with this one. What do you think about the theory of running in ketosis and accessing the pathway using ketones vs glucose at or above an aerobic level? In other words, if you have a good aerobic base or not is it possible for the body to switch and use ketones indefinately as we have fat in abundance and are limited to a finite period of time for glucose? Thanks Dr G
Sock Doc says
Indefinite is not infinite in this case. Yeah you can go a lot longer off fat/ketones but you’re never 100%. Even if you’re super-efficient maybe you’re 20% glucose(?). Additionally, I believe that over three hours of moderate intensity you’re going to push cortisol levels higher – using up more glucose & even breaking down protein to convert to glucose.
James says
I primarily run long distance races (50 – 100 miles) each month. Usually a middle-packer. I did a fairly large buildup before starting to run these long races that included a lot of aerobic HR training. My day to day running has lessened as I am recovering between the long races during the summer.
Would you recommend going back to aerobic base building after my last race (100 miles) or start some speed work once I recover physically? I am not getting any faster at present but may be do to breaking my body down and not necessarily peaking for these races… rather the accomplishment this summer has been just doing them all.
Thanks!
Sock Doc says
That’s tough to say. I personally don’t think the body can handle so many 50+ milers, especially each year. You could approach it more aerobically as you suggest, or you could also consider cutting down mileage significantly and keeping current fitness with HIIT training, and more rest.
James says
what is your opinion on how long HIIT can help to maintain fitness before you begin losing it? Thanks again.
Sock Doc says
This is mentioned in a previous comment reply.
Trent says
Heart Rate Monitor training has changed my life. After a 3-month aerobic base building period, I set a pr at several distances. I went back to once a week speed work while training for a marathon and got injured. I had about 7 weeks to train, did primarily aerobic zone workouts and pr’d by 13 minutes. This stuff works.
Christian says
Hi, more good advice, thanks. My two questions are about getting the long runs in when building up for a marathon. I note you have previously said to keep aerobic runs below 90 mins. First, given drift, when I run more than 10 miles, drift really takes its toll and I am going little faster than a brisk walk. The longer, long runs, including the 20 miler, would be spectacularly slow. My second question, is how to make yourself ready for a sustained effort at marathon pace when this might be more than 1min/km (1:30/mile) faster than aerobic pace. Also, is it OK to mix aerobic running with the sort of conditioning and strength exercises set out in Jay Dicharry’s book, Anatomy for Runners? Thanks again for all your great advice.
Sock Doc says
This one is a bit too detailed for me to get into here. Check out the Training Principles for the basics.
Ryan Myers says
So what’s a weekly marathon training schedule using this method look like?
Sock Doc says
I don’t provide free personal training programs, sorry.
Adolfo Neto says
Do you provide paid training programs?
Sock Doc says
I do training programs with athletes via consult and integrate health/diet aspects in the program.
Ryan Myers says
Is every run supposed to be aerobic?
Sock Doc says
If you’re trying to develop a certain level of aerobic fitness, yes.
Andrew says
I’ve had good results with the low HR training. I recently sprained my ankle on a trail run and was surprised how quickly my aerobic fitness faded after 2 weeks when I resumed running. Is that typical?
Sock Doc says
2 weeks is a bit quick to lose a lot of fitness.
Aileen says
My HR doesn’t seem to follow a normal pattern. When I was running lots of mileage say I was then about 35-45 years old I tried and tried to run slow and the slowest I could ever run had me at a HR of in the mid to high 140’s. If I walk my HR drops like a stone and I have trouble getting it up but running has it zooming up like no body’s business. In those days I could do a 20 km run with my HR sitting comfortably around 160 to 165 easily. Any comments?
Sock Doc says
This is not untypical with someone suffering from some sympathetic-type stress issue; in other words your nervous system is in overdrive due to some lifestyle factor or health problem. I’d have it checked out via a stress test to make sure there is nothing seriously wrong and if okay there, then have lactate testing done to see your training zones.
Aileen says
Interesting comment – the first explanation of any sort I’ve ever had! I did have a stress test at one stage, they took me up to 192 BPM and all good. I have had my DNA done and I do know I’m more suited to anaerobic exercise than aerobic – explains why after all those years of running training I was still SLOW! My RHR is good – down in the 40’s then and even now its around 52 with minimal running training though I still do quite a lot of weights. I will do some more reading. Thanks.
nikos charonitakis says
Hi all
I have a similar story 🙂
After reading maffetone books and other sources like soc doc etc i also started heart rate training and eliminated all processed foods from diet.
My trainning and diet continues to evolve.
I hope i will be confident enough to run Athens classic marathon in November…
My maf tests so far:
june (time per km)
8:09 8:07 8:11 8:42
july
7:55 7:58 8:02 8:12
August
7:17 7:31 7:32 7:37 7:39
I am pretty slow compared to miss zippy… I started running about 2 years ago at age of 43 mainly under the “no pain no gain” attitude. My personal best were ~25m for 5K and ~1:55m for half-marathon
john b says
thanks for the great article! i first heard phil maffetone on trail runner nation. I’ve been following his method for about 2 months now and it seems to be working pretty well. I’m planning on my 1st 50k in December.
I wanted to know if you could give some guidelines on heart rate for racing. I am 47 so I keep my heart rate just under 133 for my training runs. what would be a good heart rate for a 5k, 10k, 1/2 marathon, marathon or longer.
Sock Doc says
Check out the SD Training Principles, thanks.
Joe says
Amazing article! Keep up the great work. Looking forward to your book.
I’ve learned TONS from reading through your entire website and watching your videos. thanks again
Joe
Bill B says
Great to find your site! This is so timely for me as I have been thinking about many of your principles this summer as I became aware of MAF training benefits. Funny the older you get the less you seem to know! I almost can’t wait for the last race of my season next weekend to start several months of MAF training and see how it goes. I have no idea how aerobically fit I am. I do a lot of varied racing, and have always incorporated high intensity intervals. My focus seems to be moving towards towards ultra trail more than tri’s or cycling racing and I see a strong aerobic base being critical for these. I recently DNFed the Leadville 100 at mile 60 (but did finish the 100 mile bike the Saturday before!). Using Friel tests, my Zone 2 has been 125 to 135 for the bike, a little higher for the run. I feel this is correct. Using the 180 formula (I am 63) my MAF zone top would be 117, or perhaps increased by 5 to 10 beats based on age and fitness the way I read Dr. Maffetone’s directions. But, way too low for me, this would be my zone 1 recovery. My Friel tests were 157 bpm run and 154 bpm cycling lactate threshold. Thanks for all of your effort here for everyone to learn and use!
SteveL says
When I run at MAF pace I use 135HR as my target. I have been using the ithlete application to measure my stress levels for proper training. One thing I’m noticing is that on the bike my MAF HR should be around 130. When I cycle at that heart rate I generally get a good HRV score the next day versus if I use 135 on the bike I typically get a much lower score and even end up with an orange colored score indicating I need to take an easy day. This leads me to believe that on the bike when at 135 heart rate I may very well be in my anaerobic zone. Thoughts on this?
Craig says
Hi Steve, can I bother you with a question please. I recently purchased Ithlete to help my aerobic training. I was comparing sitting v standing results and was surprised to notice that my HR shoots up when I stand by an average of 30-40 beats, eg from 50 at rest and sitting, up to 80-90 beats, occasionally up to 100 beats. I checked it with other HRM equipment and it is consistent. I also checked my non-running family members and their HR goes up by only 5 to 10 beats per minute.
I haven’t come across this phenomenon before. I often get very light headed when I stand but hadn’t thought much of it. Any suggestions of what I can google to find out more about what causes this and what I can do about it? Thanks heaps if you have any suggestions. Craig.
Sock Doc says
That happens when your sympathetic nervous system is too hyped-up. It’s not normal and is similar to (or could be from) anaerobic excess. Poor sleep, too much sugar/caffeine/heroin (just kidding I hope), or even excess emotional stress can cause this. Good question; it’s more common than you think and a similar phenomenon is when your HR stays elevated too long after exercise – meaning it doesn’t come down to your resting rate for many minutes even after some aerobic exercise.
Marguerite says
I hope you don’t mind my mixing this with your Facebook page, but I don’t have a Facebook account. Postural Orthostatic Tachycardia Syndrome (POTS) was mentioned on that site as something that could cause this symptom. Craig may wish to consider whether he has been bitten by a tick. I have a friend who was recently diagnosed with POTS after having Lyme disease. She was treated for the Lyme and they told her that the Lyme is gone but that it left her with POTS.
Sock Doc says
That’s good info, thank you. Yes, infections/toxicities can definitely result in something like this.
Darcie says
Hi Dr. G! I found your site while searching for a fix for plantar fasciitis, and I got sucked in to reading most of the articles here. I just wanted to let you know how much the site has helped me in so many areas.
After reading your aerobic training articles, I realize that I have been training anaerobically for the past 6 years! I’ve done a few figure and bikini competitions over the last 3 years, so I thought I was fit, but I wasn’t healthy. I have definitely been one of those people who regurgitated the well-known “just lift and do intervals, no need for long cardio”. Even when I did do “ss cardio” it was anaerobic. I purchased a heart rate monitor and began my aerobic training two weeks ago. A fast walk is my maximum to stay in my aerobic zone. I started at 17:30 for my first mile (including 5 min warmup built into the app I use. I do 10 min without tracking mileage beforehand so I get in 15 min of warmup). I couldn’t believe that I was unable to run at all, and stay in the aerobic zone. Now two weeks later I’m at 16:30 for my first mile, with a lower heartrate average as well. I have to do a slight jog for just a few seconds, about 4-5 times per session now in order to keep my heartrate in the proper zone. So it is going slow, but I’m committed to following through. My goal is to be able to run/jog that mile and stay in my zone.
Also, I have been dealing with the aforementioned PF, and other overuse injuries. Of course, I was stretching to try to fix those things, and pushing through to make sure I got my workouts in. I couldn’t figure out why those things weren’t getting better, and why I felt that each time I was tighter than before, even though I was stretching consistently. I stopped the stretching and began doing more trigger point work with my tennis ball. The PF is doing great after much attention to the knots in my calves. I only notice it for a few (very few!) steps in the morning now, and it no longer bothers me after having my feet propped up on the ottoman like it previously would. No longer stretching, using the trigger point work, adjusting my (over)training schedule, and having more rest/recovery days is working!
Thanks so much for all of the information on your site. Also, thanks for saving me money! I was researching orthotics for my PF and your articles about orthotics are what brought me here. I was so happy to not have to buy them, as I am a barefoot girl who likes to wear shoes as little as possible. 🙂
Yuri says
Hi, thanks for very interesting site.
I have one question. I found that load/intensity of different aerobic exercises feels very different with the same HR (I’m training with HR 120-130). Jumping is harder than jogging, which is harder than going on ellyptical/walking. I have a very different feeling after jumping with HR = 125, then after going on ellyptical with HR = 125 for the same time.
I guess that this may be connected with different stroke strength (?). I feel that my heart beats stronger (but not faster) during jumping. So perhaps the amount of blood pumped is higher.
If so then all formulas shall be corrected by considering type of the exercise (?)
Any comments?
Sock Doc says
That’s because of the type of muscle fibers you’re using. Check out the Sock Doc Training Principles for more on this.
Stellarbaby says
Just wondering what your thoughts are on the mass media pushing HIIT type work outs. Also, if I am moderately athletic, but am self-admittedly slacking in the cardio (so maybe not really that athletic?).. Could a work out regimen of MWF-40min true cardio and Tue Th HIIT work outs (insanity? running hills?) be too much? I’d like to slowly work up to that routine…
Sock Doc says
Check out the Sock Doc Training Principles for more on HIIT.
Jim McGuck says
So is it fair to say that the more aerobic fit you are the longer you should be able to maintain your HR? Currently I can get about 14 miles and everything goes to crap and I have to really slow down. Should it get better and I be able to run farther same heart rate the fitter I get?