Aerobic vs Anaerobic: Are You Running At the Right Heart Rate?

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As I mentioned last week, I found some great info on the optimum heart rate level to train at for endurance sports. It is quite different from the high intensity trend that is popular today. Well I started it last week and I was very surprised at the results.  Let me tell you all about it and then you can decide for yourself if you’d like to give it a whirl.

Aerobic vs Anaerobic

So last week I started running (barefoot style) at my Maximum Aerobic Heart Rate Zone using a heart rate monitor. This zone is also known as the Lactate Threshold Heart Rate. In his book, “Slow Burn: Burn Fat Faster By Exercising Slower,”Stu Mittleman, a very famous ultra-runner and trainer, calls it your MAP zone for Mostly Aerobic Pace.  Phil Maffetone, clinician and coach, who has helped many pro-athletes recover from injuries, calls this the “Maximum Aerobic Training Heart Rate.” Dr. Maffetone has written several books on this subject including, “The Big Book of Endurance Training and Racing.”

Your Maximum Aerobic Zone

The basic formula to find your max aerobic heart rate is:

[180- your age.]

Some modifications according to Maffetone:

 a. If you have or are recovering from a major illness (heart disease, any operation or hospital stay, etc.) or are on any regular medication, subtract an additional 10.
b. If you are injured, have regressed in training or competition, get more than two colds or bouts of flu per year, have allergies or asthma, or if you have been inconsistent or are just getting back into training, subtract an additional 5.
c. If you have been training consistently (at least four times weekly) for up to two years without any of the problems just mentioned, keep the number (180–age) the same.
d. If you have been training for more than two years without any of the problems listed above, and have made progress in competition without injury, add 5.

For example, if you are thirty years old and fit into category (b), you get the following:
180–30=150. Then 150–5=145 beats per minute (bpm).

In this example, 145 will be the highest heart rate for all training. This is highly aerobic, allowing you to most efficiently build an aerobic base. Training above this heart rate rapidly incorporates anaerobic function, exemplified by a shift to burning more sugar and less fat for fuel.

If it is difficult to decide which of two groups best fits you, choose the group or outcome that results in the lower heart rate. In athletes who are taking medication that may affect their heart rate, those who wear a pacemaker, or those who have special circumstances not discussed here, further individualization with the help of a healthcare practitioner or other specialist familiar with your circumstance and knowledgeable in endurance sports may be necessary.

Two situations may be exceptions to the above calculations:
• The 180 Formula may need to be further individualized for people over the age of sixty-five. For some of these athletes, up to 10 beats may have to be added for those in category (d) in the 180 Formula, and depending on individual levels of fitness and health. This does not mean 10 should automatically be added, but that an honest self-assessment is important.
• For athletes sixteen years of age and under, the formula is not applicable; rather, a heart rate of 165 may be best.

This formula is just a starting point. You will need to also check in with your body to see how you feel in the different heart rate zones to adjust them specific to you.  I highly recommend getting your hands on either “Slow Burn: Burn Fat Faster By Exercising Slower” and/or “The Big Book of Endurance Training and Racing.” Check your local library or click the links to download the kindle versions from Amazon right now. “Slow Burn: Burn Fat Faster By Exercising Slower” walks you through, in great detail, how to sense which zone you are in. This is just as important if not more so than the reading from your heart rate monitor.

At your  aerobic zone you are generating energy primarily through burning fat. Above this heart rate you are in the anaerobic zone where energy is generated by burning sugar either from your blood or from glycogen stores in your muscles or liver. The average adult has about 2500 calories worth of stored sugar vs about 160,000 calories stored as fat. Fat is a perfect fuel for us since it is almost an unlimited supply. Sugar on the other hand is not only small in supply, but it is highly guarded by the body because it is essential for the functioning of the brain and nervous system and in cases of emergency when you need quick energy.

So the body doesn’t like this supply to be depleted, so much so that it starts sending you all kinds of signals when sugar stores drop by just 20%. If you train primarily in the anaerobic zone it can cause a vicious cycle of sugar depletion and then cravings of sugar to replenish that resource.

Why Train in the Aerobic Zone?

The reason to train in the aerobic zone is that you will greatly improve your true aerobic endurance. Over time you will see an increased pace at the same heart rate. The mechanism for this is while training in your aerobic zone, your body will build more mitochondria in your cells. These are the organelles inside each of your cells that produces energy! More of these little babies means more endurance at a given heart rate or level of exertion. So even thought it may feel that you are not pushing yourself at this heart rate zone, your body is building for better performance which you will see in your pace over time.

Until your aerobic foundation is established, you should hold off on speed or high intensity workouts. A couple weight training workouts per week are ok during this time. Once your aerobic foundation is in place then you can add in 1-2 speed or high intensity interval workouts per week being sure to have easy or rest days following. You’ll know your aerobic foundation is established when your pace/speed plateaus for your aerobic heart rate. Comparisons should be done based on monthly results, not weekly.

Why Not Just Train Short Interval Workouts All the Time?

The trouble is that most endurance athletes are frequently or even exclusively training in their anaerobic zone much more than at their aerobic zone. Training anaerobically has its place in building strength and power, but to train in this zone excessively (say only doing HIIT or interval workouts) will put a lot of stress on your body. You will suffer either way, whether you or not you see the results.

According to several sources including Stu Mittleman’s “Slow Burn” and Joe Maffetone’s “The Big Book of Endurance Training and Racing,” beware the current fad of HIIT, Bootcamp, Tabata, and other interval style works as your primary type of workout.

I know you may be saying, “Hold on a minute here. I like my short 20 minute interval workouts. This is not the information I’ve been told about my interval workouts.” You’ve likely been told that they:

  • are “fat-burning”
  • most efficient return on your exercise time
  • total body workout
  • build strength & endurance in 1/2 the time

They may be shorter in duration. You may be building strength. But you are not building your aerobic endurance. You are not burning fat as the primary source of energy. Your metabolism may be up for the rest of the day, but it will also be up for the rest of the day after a long slow run. The truth is you don’t have to push yourself into the red-zone day after day to see great results in your fitness. And you have much to lose in your health if high intensity workouts are your staple daily workout style.

Here are the problems with training too much in the anaerobic endurance zone:

  • stress on your heart that can lead to enlarged, inflamed heart. You likely won’t know about this until you get a big bad surprise.
  • stress on the hormone system causing exaggerated PMS and men’s hormone’s getting out of whack too.
  • stress on the nervous system – you’ll feel exhausted as you dangerously deplete your sugar stores.
  • stress on your muscles – because of the lactic acid buildup you’ll feel a lot of fatigue.
  • stress on your immune system and digestive system as these systems are put on hold when the body encounters “emergency” style exercise on a regular basis without adequate rest periods between days.
  • overall build-up of inflammation from these stressors, including your heart which you may never be aware of until you have an unexpected heart attack.

How to Avoid Anaerobic Overtraining Stress

For endurance athletes you should train mainly in your aerobic zone. Establish your aerobic foundation. This can take months to weeks depending on where you’re at already. Even if you’ve been running or cycling for a long time, if you’ve been doing this primarily in your anaerobic zone then you’ll have some foundation to lay down. You’ll know it is established when for a given heart rate you no longer see improvements in your pace. After a month of plateauing like this, then it is time to add in anaerobic training 1-2 or even 3 times per week, but always followed by a rest or easy day.

Why I Was Pleasantly Surprised

Running at my aerobic heart rate was so easy that it was hard to do! Why? It required so much patience. You must start over with your training at a pace that will likely feel way to slow. And way too easy.

When I ran 6 miles on last week at my aerobic zone, I literally felt like I could run at that pace all day long. It felt that easy. And that’s been the hardest part is holding back from going fast. But I am committed to seeing how this type of training will improve my overall endurance. And I’m also interested in increasing health and not just fitness. Overtraining in the anaerobic zone too much is dangerous to your health. A balance between the two is important.

I have to say that I am delighted. I have been able to increase my mileage very easily now that I am running slower. I can see now that I was only training anaerobically before. I was powering through every run. They were all hard runs. I never ran slow. Even when I set out to run slow I would always speed up. My body has been busy “surviving” that pace. In contrast training slower feels great and the time even goes by faster even though I’m going further.

It’s a pleasure now. I enjoy the slow runs knowing that I am actually improving even while being able to get back in touch with the joy of running. And I take great contentment in know that I’m not only going to improve my performance, but also improve my health.

Taking the “Risk” to Train Aerobically

In some ways it can feel like taking a risk by training long slow distances. It can feel like maybe I will lose my speed or strength. But I believe this won’t happen and I believe it’s worth the risk because:

  1. I’ve read tons of testimonials from professional endurance athletes who tell stories of how this improved their performance.
  2. I want to avoid the kind of sneaky heart problems that can creep up on athletes that train too hard too often.
  3. I want to run in the “fat-burning” zone because it leaves me feeling good and energized vs the exhausted feeling of anaerobic training.
  4. It feels great to train in this zone. I get to rediscover how much fun running is, that it’s not just a chore.
  5. I want to keep injuries and body systems (such as my immune system) from experiencing breakdowns from overtraining.
  6. I like how it affords me the mental availability to listen to my body as I transition to “barefoot” style running. (which I love!)
  7. Really, at the end of the day, what do I have to lose? I’m not a professional athlete. It doesn’t matter if I get faster or not. I can afford to take the time to see the results. It feels like a fun adventure.

The Bottom Line for You

Long slow runs will burn more fat on a percentage basis than high intensity workouts. Which burns more total fat will depend on the time you spend on either. But training your body to burn fat as a fuel by doing long slow endurance workouts will improve your body’s efficiency.

There is a place for both aerobic and anaerobic training. One builds endurance and the other builds muscle and strength. Both are good. In our culture it’s actually harder to do the easier training with so much hype out there about training hard. My goal here was to show you the benefits of slow endurance training. And hopefully you’ll want to try it and hopefully you’ll see some great results from it in both your fitness AND your health!


Slow Burn: Burn Fat Faster By Exercising Slower” by Stu Mittleman – excellent guide to running in the correct heart rate zone for maximum performance, health, and fitness.

The Big Book of Endurance Training and Racing” by Dr. Phil Maffetone – also a great guide like “Slow Burn” with additional information on barefoot running as well.

Convict Conditioning” by Paul “Coach” Wade. Personally I think this is the best way to build muscle. Using body-weight compound exercises you will build strong balanced muscles and avoid unbalanced muscle development and injuries. Also, the training time is shorter than traditional weight lifting protocols. It’s strenuous, but efficient and produces great results. Plus I think it’s more fun.

MIO Alpha I Strapless Continuous Heart Rate Monitor – the heart rate monitor I purchased. It requires no chest strap. For me that’s huge because I used one in the past and found it too uncomfortable to wear. This wristwatch style works great. I combine it with the MapMyRun app on my iphone where it will talk to me and give me updates on my heart rate. It uses cutting edge technology to accurately measure your heart rate and it uses bluetooth to to pair with many different types of devices.

This video explains aerobic vs anaerobic very well:

What Do YOU Think?

What is your experience with this? Are you interested in trying it? What do you want from your running/exercise?

Let’s Chat! Please share your thoughts in the comments below or on Facebook or Twitter. (links are below)

photo by: qthomasbower

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  1. Kris May 11, 2014
  2. David August 13, 2014
    • Kris August 13, 2014
  3. David August 14, 2014

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