The 5 Zones of Cardio
What They Are + Benefits of Each
I don’t typically talk about all types of cardio here, but I figured, why not? We should all have an understanding of what kinds of cardio there are and how you can apply them.
The “5 Zones of Cardio” I am referring to are the Heart Rate Zones - Very Light, Light, Moderate, Hard, and Maximum.
Heart Rate Zones are just a way to monitor and keep track of how hard your heart is working during a workout (or any activity really). These zones are measured in regard to your maximum heart rate.
Any workout plan including various levels of intensity, frequency, and duration will be effective for optimal heart health. Zone 2 will always be my go-to, but I like to work in different ranges for different goals I have in the gym during certain blocks of my programs.
It’s good to work all zones of cardio at some point in your training regime—having this versatility will train your heart from every angle. Some workouts should be short and intense (sprints or HIIT), others long and light (Incline Walking at 3.0-5.0 speed), and some should be long and difficult (think marathons).
When I’m referring to intensity, frequency, and duration, these are the definitions I have in mind:
Intensity - measured by your heart rate zone and how “hard” you’re training, e.g. Zone 2 isn’t as intense because your heart rate zone is within the “light” level vs something like Zone 4 where your heart rate is working at “hard” level.
Unlike a purely subjective evaluation of intensity, your heart rate is a number you can measure, just like frequency and duration.
Frequency - how many times you exercise per period of time, e.g. 2-3x per week, 8-12x per month, 96-144x per year, etc.
Duration - how long you exercise at a time, usually counted in minutes. e.g. 20-30 minutes of incline walking on the treadmill. OR something like 2-3 minutes of running, 2 minutes of walking, 2-3 minutes of running, 2 minutes of walking, ad infinitum, etc.
So What Exactly are HR Zones?
We all have unique resting, minimum, and maximum heart rates. Between each of these “measurements” are different heart rate zones that coincide with our level of training intensity and benefit.
Resting HR - your “pulse” - “the number of times your heart beats per minute when you are at rest — such as when you are relaxed, sitting or lying down1.”
Minimum HR - the range between resting HR and maximum HR.
Maximum HR - “the greatest number of beats per minute your heart can possibly reach during all-out strenuous exercise.”
Qualities/Factors that affect and influence Heart Rate:
Age
Fitness and activity levels
Environmental factors: air temperature, quality, altitude, etc.
Having cardiovascular disease, high cholesterol, or diabetes
Body position (standing up, sitting, lying down, etc.)
Feelings (like anger vs excitement)
Body size: height, weight, (even posture2 too), etc.
Other things like taking medications, smoking/tobacco use, alcohol use, other drug use, etc.
There are numerous ways to calculate and identify your personal heart rate zones (more on this later). The main way is to define them as percentages of your maximum heart rate.
These zones are directly related to the level of aerobic and anaerobic thresholds.
These are two different types of exercise that differ based on the intensity, interval, and types of muscle fibers incorporated3.
Aerobic - relating to or denoting exercise that improves or is intended to improve the efficiency of the body's cardiovascular system in absorbing and transporting oxygen.
Anaerobic - relating to or denoting exercise that does not improve the efficiency of the body's cardiovascular system in absorbing and transporting oxygen.
When considering which type of exercise you want to perform, it is important to understand the differences between aerobic and anaerobic training.
Examples of Aerobic
Swimming
Cycling
Elliptical
Walking - treadmill, incline, outside, etc.
Rowing
Examples of Anaerobic
HIIT
Weight Lifting
Circuit Training
Pilates
Yoga
Other forms of Strength Training
So, how does this all connect?
Defining the 5 HR Zones
We have 5 different zones in which we measure our heart rates. In this table, the heart rate zones are explained by the level of intensity and percentage of Maximum HR used in each one.
Here is a breakdown of what each heart rate zone means and what the benefits of training in that specific heart rate zone are.
HR Zone 1: 50–60% Of HRMax - Very Light
This is very low-intensity, low-impact cardio. Training in this range will boost your recovery and prep you to train in higher HR zones. (Commonly known as “active recovery”).
Something like going for a walk (like a very light walk) will have you in this HR zone. It should be a very controlled, easy type of cardio. Think about your daily 10k steps here - this is pretty much “passive” cardio.
Summary of Benefits
Increased Endurance.
Durability.
Fat Utilization.
Oxygen Efficiency.
HR ZONE 2: 60–70% Of HRMax - Light
As I mentioned before, this is my favorite type of cardio—my go-to.
This zone is also light, low-impact, and low-intensity cardio. You should be able to do this for a while without stopping. But you also won’t be out of breath by the end of this workout.
Working in this HR zone will increase your endurance4. At this level, our bodies are more susceptible to burning fat (oxidizing fat) and increase our muscular fitness with capillary density.5
This is probably the most beneficial and essential type of cardio that should be utilized in every workout regime (I recommend 2-3x @ 20-30 minutes per week - same as Ox).
(This is also the Zone of Cardio that got me shredded for prep utilizing 30-40 minute sessions 3-4x a week).
Summary of Benefits
For more details,
has a post (I linked above) with .Increase in # of mitochondria.
Increase in mitochondrial efficiency.
Increase in “metabolic flexibility”
Lower resting heart rate.
A decrease in blood pressure.
Lower risk of injury.
Improves insulin resistance.
Improves your ability to run/cycle longer.
HR Zone 3: 70–80% Of HRMax - Moderate
Training in Zone 3 is crucial for improving blood flow and circulation in the heart and skeletal muscles.
Training in this HR zone regularly will make other zones easier to perform and the overall efficiency of your heart health will increase.
Jogging, maybe a little bit of a run. Cycling at a higher level. Anything that hikes your heart rate up higher than brisk walking (hehe, yes forms of hiking too).
Summary of Benefits
Effective Fat Burn.
Strengthens Muscles.
Builds Endurance.
Increased Blood Circulation.
HR Zone 4: 80–90% Of HRMax - Hard
In this zone, you will notice that it is getting harder to perform. The workout is much more intense. By this zone, you will be breathing harder and working aerobically.
This level of intensity will improve overall speed and endurance.
You won’t get many words out if any while performing this level of cardio.
Running/sprinting, going pretty fast here. Assault bike… Heavy Rucking, whatever you want to do, just go fast, Forrest!
Summary of Benefits
Helps your body train itself to endure long bouts of speed.
Uses more carbohydrates as fuel.
Withstands more lactic acid accumulation.
HR Zone 5: 90–100% Of HRMax - Maximum
This level will be considered your maximal effort. Both your respiratory system and heart will be working at their maximum capacity. This should be performed in “spurts” as it is very taxing on the body.
FULL-OUT SPRINTS!!! Assault bike at peak levels, anything that gets you at full-speed and your heart maxed out.
Summary of Benefits
If not done to exhaustion, builds mitochondria in fast-twitch muscle fibers which = more endurance.
Trains max speed.
Increases your anaerobic threshold - this makes your heart work more efficiently.
Estimating/Calculating Your HR + Zones
Here are three different formulas (methods if you will) that can be used to calculate and estimate your maximum heart rate:
[ 220 – Age ] - The most commonly used method to calculate your maximal HR.
[ 207 – 0.7 x Age ] – This is a more precise formula, this is adjusted for people over the age of 40.
[ 211 – 0.64 x Age ] – This is a slightly more precise formula than the one above, adjusted for generally active people (“athletes”).
How to calculate your resting heart rate:
Place two fingers between the bone and the tendon over your radial artery — which is located on the thumb side of your wrist. When you feel your pulse, count the number of beats in 15 seconds. Multiply this number by four to calculate your beats per minute.
Some can’t feel their pulse at this wrist, if this is you, try this method instead: Place your index and third finger on your neck to the side of your windpipe. Again, when you feel your pulse, count the number of beats in 15 seconds. Multiply this number by four to calculate your beats per minute.
Here is a calculator that can estimate each of the 5 HR zones, given you know your resting HR and Maximum HR (you should, I gave you the recipe!!!).
Other Tracking Methods
Many factors will affect your heart rate (most listed above), so the best method would be getting some kind of active wearable like Whoop, AppleWatch, Garmin, Oura Ring, FitBit, etc. that can track your heart rate ranges and training in general. This will be a little more accurate as these devices can track factors like sleep patterns, sleep quality, daily activity levels, body temperature, and much more.
Some, not all, cardio machines also make it easy to track your heart rate and have a chart of the zones you can follow. Just input your stats and use the metal “place hands here” trackers and you will have a heart rate pop up on the screen. I’ve experimented with them to see how accurate they are in comparison with my Whoop (and Apple Watch) and they are spot-on.
Disclaimer: I don’t trust machines, or wearables for that matter, to track how many calories I’ve burned. There are many factors that affect how many calories are burned during an activity and you can bet most of the time there isn’t a precise way to measure the true, exact amount. Just keep in mind “calories burned” from these devices are just estimates.
If you want to read more about how the body burns calories, check out this post and this post from Ox.
Just to Reiterate
You want to keep variety in your training regime to improve overall fitness. Working in different ranges, levels of intensity, varying durations, etc. will be most beneficial for anyone wanting to be “good” at multiple forms of cardio and will ensure you get the most out of your efforts.
You will also become more aware of how your body performs in each zone. Don’t get stuck in the cycle of working at the same level each time you do some form of cardio. Explore each level of intensity and implement what works best for you.
I do not recommend doing each of these every single day, so please don’t read this and have these thoughts. Train based on your goals!
Unrelated but kind of related - check out this study from 19826.
That’s All Folks!
So there you have it.
All 5 zones of cardio and how each can benefit your training!
Why stick to one when you can train in each one?
Happy walking, running, biking, hiking, swimming, ok ok ok I’m done! LOL.
Happy exercising Frens!
#WAGMI
Your friend,
- BowTiedHeifer
Disclaimer
I am not a licensed personal trainer or pre/postnatal specialist—these are simply my personal experiences and things I have witnessed to work for many others. This is not legal, medical or financial advice. Please speak to a professional before starting any new programs, applying any new diet plans, or supplement protocols.
Endurance - Exerting and remaining active for a long period of time—also the ability to resist, withstand, recover from, and have immunity to trauma, wounds, or fatigue.
Capillary Density - Defined as the number of capillaries per unit cross-sectional area of muscle.
Yoga is anaerobic now? lol. Btw all the aerobic activities you mentioned can be done anaerobically, depending on the intensity, aerobic and anaerobic refer to the formation of ATP, mitochondria either use oxygen, aerobic, or lactic acid, anaerobic, to create energy (ATP).