Zone 2 Training
What is it?
A form of training utilizing specific heart rate zones to maximize aerobic function through building mitochondrial efficiency and fat as fuel utilization rather than carbs.
Why do I care?
As an endurance athlete this is how you build speed over longer distances and also decrease your likelihood of injury because you are training at an overall lower intensity
How do I find my Zone 2… Zone?
Free, Low to No Effort: MAF (Maximal Aerobic Function) Method
The simplest way to get an idea of your top zone 2 heart rate is as follows:
180-Age= Max Zone 2 HR, subtract additional beats for each of the following scenarios
If you are recovering from major illness (heart disease, any operation or hospital stay, etc.), in rehab, take regular medication, or are chronically overtraining , subtract an additional 10.
If you are injured, regressed or plateaued in training or competition, get more than two colds, flu or other infections per year, have seasonal allergies or asthma, are overweight, are slightly over trained, or been inconsistent, just starting, or just getting back into training, subtract an additional 5.
If you have been training for more than two years without any of the problems listed above, have made progress in your MAF Tests, improved competitively and are without injury, add 5.
Free, high effort: Karvonen Method
The Karvonen Method, like the MAF method, is another math equation that is just slightly more complex. The equation is as follows:
[(Max HR - Resting HR) x %Intensity] + Resting HR = Target HR
In order to find the limits of your zone 2 heart rates the intensity should be 60-70% so you would plug in “.6” to the %Intensity part of the equation and then again plugging in “.7”.
The “high effort” portion of this method comes from finding your actual max HR. Sure, you could just do 220 - your age but this hasn’t been very accurate for a lot of people who may have an above or below average max HR.
So, how do you go about finding your personal max HR?
Well, one effective method would be doing two max effort 400 meter intervals after a 10+ minute warm up. You could also try a couple all-out hill sprints over a shorter distance.
Whatever you choose to do, the first interval should elevate your HR substantially. Look at the peak HR after the first interval and, if it doesn’t go any higher during your second interval, that is your max HR.
The point is, you have to put it all out on the line and make it hurt (probably a lot). It also helps to have a device measuring your heart rate as taking an accurate manual heart rate can be challenging immediately after a max intensity effort. In my experience a chest heart rate strap is ideal, wrist HR monitors can be significantly inaccurate.
Lactate testing
This method is primarily for individuals with metabolic diseases such as diabetes, or, super nerds (which is totally cool, if you wanna geek out, geek out!). It involves pricking your finger with a lancet, placing it on a lactate strip, and plugging it into a lactate reader (which you can find here: https://www.edge-usa.com/lactate-meter/ ). The way you would find your zone 2 using these is to workout while tracking your heart rate while testing your lactate. Obviously pricking your finger 20 times in a workout doesn’t sound like an enjoyable experience so for maximum efficiency I would start with finding your estimated zone 2 heart rates with the Karvonen method, work up to the peak of that mathematically defined zone and test your lactate then. If your reading is just under 2 mmol/L (or 36 mg/dL - some of these devices provide different units) that is your maximum heart rate for zone 2.
How do I know that I’m in Zone 2?
Conversational pace
The most cost efficient way to know if you are in zone 2 is if you are able to have a conversation while performing the activity. You want to be right before the point where you feel like you can’t chat about the weather with someone but you shouldn’t be able to hide the fact that you are exerting yourself.
Wrist heart rate
The next level up that involves an expense but also the ability to start tracking your data is a wrist heart rate monitoring device. These include Apple watches, Garmin, Whoop, FitBit, or several other brand name watches that allow you to track your workouts with a heart rate reading.
While these are a step up in terms of being able to track your performance as compared to the previously mentioned, “See if you can talk but not well” method of tracking your zone 2 workouts, they still are not ideal. If you are running, biking, swimming, or doing other activities that would involve a lot of jostling, pressure on your wrists/forearms, or submersion the watch’s ability to track your HR accurately, or at all, can be compromised.
So, what can we do about it?
Chest strap heart rate
The best answer for myself has been a Chest strap HR monitor that connects to my watch and phone. I use the Garmin HR-M Pro but there are other options available. The chest strap, compared to the wrist HR monitor, is much more accurate when actually measuring your HR. It is negligibly affected by any jostling during a run and it sits right over the thing you’re trying to measure (your heart).
This option has been ideal for me because I can set up my workouts on the Garmin app to keep me within a certain HR zone, sync it to my watch, throw on the chest strap, and go do my workout. I don’t have to waste extra time or energy constantly checking if I’m in the right HR zone because my watch will yell at me if I veer outside of it.
Lactate testing
One extra way to measure your zone 2 workouts would be through lactate testing where you essentially prick your finger and measure it using lactate strips at 15 minute intervals during your workout to make sure your lactate is under 2 mmol. Now, this may sound ridiculous; however, it can be a useful tool for individuals with certain medical conditions, particularly diabetes. If you, or your doctor, believe that you have a higher baseline lactate levels AND those levels rise at a higher rate then the previous HR zone equations mentioned above might not mean anything because you’re not actually working in a fully aerobic capacity.
How much should I do for Longevity? Performance?
Let’s preface this topic with examples of what longevity and performance look like for different people. After all, if I told a powerlifter attempting to reach a max deadlift of 600 lbs that he needs to do 10 hours a week of low intensity cardio on a bike… well, he may be inclined to drop that deadlift on my head.
We can define longevity in two primary ways, lifespan (essentially starting the clock the day you’re born and stopping it when you die) and healthspan (how many of the years out of your life that you are able to perform physical, mental, and social activities that result in a personally fulfilling and meaningful life). Many people towards the end of their lives experience significant limitations in their capabilities that restrict them from truly enjoying their lives. Zone 2 cardio, is one essential tool we can use to combat the likelihood of this happening.
So, if you want to be able to make it up a flight of stairs when you’re 80 years old without needing a 5 minute sitting break or pick up a bag of mulch to tend to your garden when you’re 90, zone 2 is large piece of the puzzle to accomplishing those goals.
Most research points to 4-6 hours of zone 2 per week being optimal for improving cardiovascular health and function. With that said, if you are starting off from doing nothing, doing something will be better. There is nothing wrong with striving to complete 180 minutes (or 3 hours) per week, broken into 10 minute bouts if you are just starting out or coming back from an injury/illness.
When it comes to performance the limit for improvement is rather high. There are some professional endurance athletes who push 30+ hours per week of zone 2 training on top of higher intensity work. With this said the answer really depends on your goal. If you’re working full time and attempting to train for an Ironman, you may peak at around 12-18 hours per week. Shorter races can obviously take less of a time commitment but in terms of gains, if you are a regular human and not a professional mutant, it is going to be hard to hit a ceiling where you wouldn’t see performance benefits from doing more zone 2 work.
