Zone 2 Heart Rate Training

Zone 2 Heart Rate Training

About 8 minutes of reading time.

There are many ways to train using heart rate. Zone 2 is a sort of magical heart rate zone and is excellent for several reasons! For this article’s purposes, Zone 2 is 60-70% of your ACTUAL maximum heart rate. For most people, this is merely a brisk walk! More on maximum heart rate will follow at the end of this article.

  1. Increases cardiovascular function.
  2. Produce more mitochondria, the energy powerhouses for your cells.
  3. Builds a strong aerobic base allowing you to run faster at a lower effort.
  4. Burn a higher percentage of fat with less stress/impact on the body!
  5. Do not calculate maximum heart rate!
  6. How to determine maximum heart rate.

I first really learned of “Zone 2” after being inspired by reading one of Running Coach Todd Charnetski’s articles about running slower to get faster. It was very similar to Zone 2. I want to share with you first and teach you how to determine it along with its health aspects. Not everyone is a runner, so that comes later.

Does Zone 2 Training Increase Cardiovascular Function?


Zone 2 or “low heart rate training” over a period of time will make your heart more efficient. This is by allowing it to pump a larger amount of blood per beat-stroke volume, in addition, capillary density increases.

Zone 3 (70-80% of maximum) is a gray zone as far as running goes. It does have some benefits that tie in with the cardiovascular improvements of Zone 2. These include building more capillaries to transport oxygen-rich blood. For this reason, I like to incorporate some Zone 3 training.

Interval training (such as running a minute and walking a minute) and HIIT (High-Intensity Interval Training) work the anaerobic system more and also makes the heart stronger (think of curls making biceps stronger), so it can pump the blood more forcefully per beat.

Zone 2 provides an excellent foundation for a more efficient heart which translates into all other aspects of fitness. Zome 2 training should be incorporated into a training plan that includes the other zones–when you’re ready. There’s no way I could have done HIIT or even sustained a minute at Zone 4, let alone touch Zone 5 a month or two after the heart attack! Fast forward about two years to March 2021, and I was able to run a 5K, and 90% of it (21:24) was in Zone 5, where I averaged 179 BPM and placed 3rd in my age group. If I used that bogus 220-AGE formula for my max heart rate, I would have missed out on a lot!

More interesting reading on this topic.

  • This is an excellent article about Zone 2 training, and I encourage you to read it. ESPECIALLY if you have the idea that you should spend all your time doing HIIT or other higher heart rate training and think Zone 2 is a waste of time.
  • Here is a study regarding Sprint Interval Training (similar to HIIT as mentioned above) and Endurance Training (more like zone 2). The result is that endurance training resulted in more cardiac output (stroke volume) than interval training.
  • Here is a study regarding the effect of 12 months of endurance training in patients with cardiovascular disease. (They used a percentage of VO2Max instead of “zone 2” but was similar.) The conclusion stated, “Previous studies have shown that patients with coronary artery disease respond to 2-4 months of mild-to-moderate exercise training with adaptations in the autonomic nervous system and skeletal muscles that result in a slower heart rate, a lower systemic vascular resistance and an increased capacity to extract from the blood during exercise. The present results provide evidence that if training is continued and progressively increased in intensity, duration and frequency, some patients with coronary artery disease can, over 12 months, have improved cardiac function as reflected in an increase in stroke volume and stroke work.”

Zone 2 Training produces more mitochondria and power!

Have you ever heard “exercise gives you energy?” That always intrigued me, and I think this might be why. The mitochondria are basically the powerhouses of cells. How do we get more of this energy? It is NOT caffeine or sugar! It’s more Zone 2 training.

Read this article about Zone 2 training and mitochondria. It is long but VERY informative and sums up many different articles I’ve read in the past. To quote it and whet the appetite, “During Zone 2 training, you will increase your number of mitochondria, mitochondrial efficiency, and increase your metabolic flexibility.   Metabolic flexibility refers to the ability of your mitochondria to utilize fat and glucose as an energy source (substrate).

At low heart rates, your main source of fuel should be fat… not glucose.  Poorly functioning mitochondria, which is likely to be found in ~ 75% of people will result in metabolic inflexibility or the inability to utilize fat versus glucose.” And also, “Poorly functioning mitochondria, or “mitochondrial dysfunction” is seen in people with heart disease, dementia, Type 2 diabetes, Metabolic Syndrome, cancer, and so on. The mitochondria in your immune system will dictate how well your immune system will perform.” Interesting right? Be sure to read that article.

Get faster by running slower in Zone 2?

Faster half marathon time within 13 months. Results shown from
Click to view larger.

Coach Todd Charnetski owner of Smart Approach Training and heavily involved with the I Love to Run Community on Facebook has been such a wealth of information offering suggestions to help my running game! One of his articles was titled “How to Train Smarter,” reading it was like a switch turning on that light bulb in my head.

Running slower most of the time or Zone 2 running results enabled me to get an 8:54/mile 5K pace down to a 7:12/mile 5K race pace in one year; and my half marathon from 11:55/mile to 8:47/mile in 13 months! 😲 Strength training and speed work/intervals also contributed, but building my base with Zone 2 was key.

I hope Todd’s article enlightens you as it did me. This started my fascination with Zone 2 heart rate training.

Burn fat by low heart rate training?


Lost inches by burning fat from Zone 2 heart rate training. (And eating less calories than burned.)

Don’t get too excited, as this isn’t the holy grail of fat loss. Exercising in this lower heart rate zone burns fewer calories per minute than at higher heart rates. This is when you burn a higher percentage of fat as fuel; however, it takes a lot of time to burn off the calories, and weight loss is fewer calories consumed than calories burned. Again, weight loss IS fewer calories consumed than calories burned!

The benefit of fat burning in Zone 2 is, as I stated earlier, “burn fat with less stress/impact on the body.” Higher heart rates will cause more stress and impact. It may take you longer to burn the same calories in zone 2 as it would at zone 4, but you more than likely won’t be able to last the same amount of time in zone 4 as you could in zone 2 due to the impact on the body. This is a great zone to be in if you’re starting out exercising, and if you can train longer, then that means more calories are burned.

Higher heart rate training has many incredible benefits, but it works with different energy systems. You will end up burning MORE fat at these higher intensities even at a lower overall time while a lower percentage of fuel is fat; however, as I mentioned earlier, it puts more significant stress on the body. Unless you’re somewhat already fit, I wouldn’t recommend getting up to higher heart rates. It took me a while to get comfortable with this, even though I didn’t have any restrictions at the time.

Do low heart rate training to burn mostly body fat.

  • Spend 30-45+ minutes a day in zone 2 = lightly breaking a sweat and/or the ability to easily have a conversation with a partner.
  • Strength train at least 2-3 days a week, even if modified bodyweight exercises for beginners.
  • Rest. It is still a good idea to keep moving. Go for a leisurely walk at the park instead of zone 2. Rest days are great for gains (just not a whole year’s worth of rest days as I did for 20 some years. 😇) Rest ≠ lazy 😉.
  • Keep progressing. You’ll end up in a running gait by spending time walking fast while in zone 2. Then you could probably start getting into higher heart rate training. Check with your doctor if in doubt. When the exercises get easy regarding strength training, start working with weights or more weight progressively increase the load on the muscles.
  • If you want to lose weight in addition to burning body fat, eat fewer calories than you burn. Preferably by eating clean!

When I’m at the gym, I see many new people come in and never return. I believe many quit because they burn themselves out too soon, or want instant results. It appears to me that think they must give it all they have on a treadmill, elliptical, or whatever for an hour. I run a lot and am now fit, and I’m here to tell you, I DO NOT EVER go that hard of effort as those people do for that long on a regular basis. It is pointless and will only cause more harm than good and lead to injury-fast. If you are just getting started, start slowly, progress, and stay with it. Trust the process!

Don’t calculate your maximum heart rate.

Your maximum heart rate is NOT guaranteed to result from any equation that uses your age, typically 220-AGE=Max HR. Those are bogus formulas initially based upon a sampling of small data that wasn’t representative of the general population! I liked this article the most actually tells you how that stupid formula came into existence.

I know that formula is wrong because I was running and conversing with a friend who is a triathlete. The conversation was a bit labored, but I conversed with Jeff just fine. I looked at my watch, and I said, “I need to slow down; I’m at my peak heart rate!” He laughed and replied, “If you were at your maximum, you couldn’t talk the way you are. You’d be ready to puke and pass out!” So we kept running, and I didn’t puke or pass out.

I was 44 at the time, and 220-44 is 176. So obviously, that formula was wrong. I think I ended up with a heart rate of 182 at the end of that run. I could still talk! This video is from a different run (shortly after I was taken off of the beta-blocker) but shows that I can talk pretty good at past the calculated 220-AGE formula result.

What is my Maximum and Zone 2 heart rate?

After knowing what your maximum is, Zone 2 is typically then calculated as 60-70% of that maximum.

I now use Heart Rate Reserve which considers my resting heart rate for the zones. This is only good if you wear your watch at night when you sleep. Logically it makes more sense to use Heart Rate Reserve because two people with the same max could have drastically different fitness abilities.

Heart Rate Reserve Zone 2 is calculated as ((MAX – Resting) * 0.6) + Resting & ((MAX – Resting) * 0.7) + Resting.

So if they both had 180 maximum and one had a resting of 40 and the other was 65, then it makes sense that zone 2 for the person with 40 is 124-138 vs the person with a resting of 65 would be 134-145.

I have written an entire post regarding maximum heart rate, zones, and fitness trackers. Check it out here.

Is Zone 2 or Low Heart Rate training a waste of time?

Absolutely not. Adrenaline junkies won’t like it very much, but I’m here to say that it works very well over time! I don’t call improving cardiovascular function, producing more mitochondria, building a stronger aerobic base, burning fat, and getting faster a waste of time. Do you?

Putting it all together.

Heart rate zones from the Zones app from Apple App store.

I don’t really follow a training plan, but my “Zone 2 training plan” is basically spending around 80% of my weekly runs in Zone 2 and the other 20% doing intervals and other speed work. Here is a very cool app for iOS that you can see the percentage of times in different training zones. Yes, I love running and it is the bulk of my training, but isn’t everything!

I truly believe that the Zone 2 training was a key component in getting me off the overnight supplemental oxygen therapy. In fact, my cardiovascular function now is night and day above when I first started this fitness journey back in early 2019. My stress test in June 2020 and my echocardiogram in December 2020 both yielded results that were music to my ears, “You’re at a VERY VERY MINIMAL risk for another heart attack! Keep doing what you’re doing!”

By utilizing Zone 2 training after my heart attack, I have made significant health improvements by burning fat with minimal stress to my body, improved my cardiovascular system, provided a boost in my mitochondria for cellular energy (CoQ10 has also helped), and safely increased my miles and gotten faster at both my easy paces and my race paces all from training a lot at slower paces.

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