Heart Rate Zones – Complete Guide To Endurance Gains
I used to be really bad at listening to my body. In fact, I’d even ignore it trying to push through the pain. The concept of heart rate zones was foreign to me and the main effort I knew was “beat other teammates”.
My attention was all over the place. The only place it wasn’t at was my body. I compared myself with others and tried to replicate or “beat” them in every training session, which mostly left me tired, over-trained and frustrated from not seeing desired results.
Heart rate zones help to focus on personal goals
While talking with other athletes at one of my first training camps I learned that coach asks them to wear a strange device during training. It was 2005 and the word ‘heart rate monitor’ was not popular. I had no idea what that was or why it’s needed, but was eager to learn. So, I approached the coach to find out.
He told me that he analyses heart rate training data after every session to see how well his athletes execute training programs and how their bodies react. What he also told me was that
It takes a lot of mental strength to push hard during training, but it’s much harder to know when to pull back.
That way, adjusting the training plan to the athlete’s current condition will lead to better and more sustainable results.
To say I was hooked would be an understatement. Until then I only had an on/off switch and thought you go hard in training, recover and repeat the next day. I had no idea how much opportunity there is in varying training intensity. Most importantly, that you can actually quantify and measure it.
I got my first heart rate monitor within months of returning from that training camp and used it daily to track my heart rate before, during and after sessions ever since.
Over the years I learned how my body responds to stress, what effect different intensities and training sessions have on it and, ultimately, how training programs should be designed/adjusted and executed.
Heart rate helps to monitor current fitness condition
During training heart rate serves as a good reference point and, unlike power or speed, shows how intense the effort is on the body. It’s aligned with current condition and will be higher if body is under more stress.
An athlete may be tired, had a restless night or fighting a cold, all of which can impact the session. Focusing on maintaining a certain speed or power in such case will more likely cause more harm than good.
Heart rate zones help to train at required intensity according to the current condition and not unintentionally pushing the body over the limit.
Using heart rate zones in training quickly improved results from my training efforts, as I learned to listen to my body and was able to better focus on my improvement areas.
I noticed that in most cases what felt like 70% was often 80% or even 90%, as I got carried away competing with others.
It was very useful to finally know what and how to focus on. Over time I learned to balance fatigue and noticed that results from my training improved substantially. I had more energy to go hard when it was required. Also, I recovered much quicker from sessions, as I was not draining energy in vain.
So, how does this all actually work?
5 heart rate zones explained
So what are heart rate zones?
Each training intensity triggers a specific physiological process and adaptation in the body. Structuring sessions around a certain effort allows athletes to customize their training and adapt it for specific needs.
In essence,
Heart rate training zones are ranges of intensities where the heart rate falls in.
Zones are always a reference to maximum capacity, so knowing athlete’s maximum heart rate is a pre-requisite for setting these up.
There are five heart rate training zones that categorize every intensity level. To calculate heart rates all you need to do is input your maximum and resting heart rate in the fields below (or in this calculator):
| Your Resting HR: (or use 60) | |
| Your Maximum HR: (or use 220-age) | |
| Zone | Effort | Target Heart Rate* | Training Benefit |
|---|---|---|---|
| ZONE 1 | 50% – 60% | – | Warmup / Recovery |
| ZONE 2 | 60% – 70% | – | Base Fitness |
| ZONE 3 | 70% – 80% | – | Aerobic Endurance |
| ZONE 4 | 80% – 90% | – | Anaerobic Capacity |
| ZONE 5 | 90% – 100% | – | Speed Training |
Target Heart Rate is a heart rate adjusted for both maximum and resting heart rates. Using this formula will provide more accurate zones, compared to simple percentage of Max HR.
Once heart rate zones are calculated, next step is to create a structured training plan. Every phase of that plan should focus on specific area (endurance/power/speed), measured in time spent in relevant zones.
And that’s all the magic.
If you don’t have a coach, I’d be happy to create a program and coach you. Go to my personal training page for more info.
Heart Rate Zone calculation accuracy
There are concerns that heart rate zones that are estimated are too generalized and may not be overall accurate. However, actual zone ranges tend to deviate only slightly for each individual. This is not enough to significantly impact the overall benefit from focused training.
Yes, the most precise way to determine heart rate training zones would be to take a supervised VO2 max lab test. Such test measures the speed of lactate accumulation and respective oxygen intake throughout the exercise. Based on the data aerobic and anaerobic thresholds are established which are key reference points in determining heart rate zones.
Over the years and multiple lab tests, however, I noticed that these ranges tend to deviate only by around 1-2% (up to 5 bpm).
Polar Vantage V2 Multisport GPS Watch
Wahoo Tickr X Bluetooth HR Chest Strap
Garmin Fenix 6 Pro Multisport GPS Watch
What is low and high intensity training?
There’s a bit more than percentages behind the concept of training zones.
As we increase intensity of an exercise, the body changes the way it sources energy. At low intensity, body primarily uses oxygen (aerobic mode) to convert fats into energy. That process is slow, so at high intensity when the body needs energy fast it focuses on converting carbohydrates (sugars or stored glycogen) to energy instead. This does not require oxygen, so it’s called ‘anaerobic’ mode.
Logically, high intensity training is more taxing on the body and should be approached carefully. Too much too soon can cause all progress to stall and put the athlete into a plateau for quite a while.
To simplify things, there are virtually 2 points around which training zones are organized – aerobic and anaerobic thresholds.
How aerobic & anaerobic thresholds impact heart rate zones?
Aerobic Threshold is the intensity level after which the body starts to slowly accumulate lactic acid (or muscle fatigue). The effort at this moment is still not that hard, so the athlete is able to maintain it for 5,6,7 hours and more.
The higher the aerobic threshold – the faster an athlete can swim/bike/run/etc. for long periods of time.
Anaerobic Threshold, on the other hand, is the intensity level after which the body cannot deal with muscle fatigue anymore. It starts to build up very quickly and there’s very limited time that this intensity can be maintained (minutes only).
More time spent in training around the anaerobic threshold will make muscles more resistant to lactic acid build up. This will help to maintain very high speed for longer (critical for races of 1-5 minutes in duration).
The good news is that both thresholds can be ‘improved’ through a mix of low and high intensity training. That’s why it’s critical to have a training plan with a specific mix of heart rate zones focused on the goal race distance.
Zone 1 training – warmup & recovery
Effort: very easy
Target heart rate: 50% – 60%
Duration: all day, if needed
Zone 1 is the exercise intensity up to the level of the aerobic threshold. The intensity is so low that all lactic acid accumulated or produced in the muscles is being utilized (the line on the graph above goes down or remains horizontal).
Zone 1 training feels almost effortless and i’s the pace you can easily maintain for a whole day (with rest and lunch stops, obviously). It’s the time to chat with others, as it’s possible to hold a conversation, and focus on proper technique.
Spending extended amount of time in Zone 1 “stretches” the heart and allows it to pump more blood. After this point it’s only the heart rate that increases.
Zone 1 training benefits
As this is a very low intensity zone, training in it doesn’t add fatigue.
Instead, it promotes blood flow to the muscles, which speeds up recovery between intervals or harder training sessions.
Heart rate zones – sample Zone 1 training sessions
- Warmup, cool down and recovery between intervals during hard sessions
- Short recovery sessions of up to 40 mins entirely in Zone 1
- Long base-building sessions of 2+ hours
- 60 minute Zone 1 session with 5-10sec bursts at Zone 5 every 3-5min
Zone 2 training: aerobic base / easy pace
Effort: easy
Target heart rate: 60% – 70%
Duration: 1+ hours
Zone 2 is the exercise intensity just after the aerobic threshold. Exercising in this zone still feels easy. So easy that you may feel you’re not training hard enough – the athlete should be able to breath through the nose the whole time.
But that’s the beauty of it – by spending extended amount of time just over aerobic threshold the body gradually becomes more endure and is able to go faster at low intensity.
Over time body will get better at burning fat and overall muscular endurance will increase, making you much faster.
Even elite athletes racing in Ironman triathlon spent at least 8 hours completing the course and most of the time is spent in high Zone 2. And these guys are able to run a 2:40 marathon at this intensity.
Zone 2 training benefits
Zone 2 is important for all athletes, but is critical for endurance athletes. Training in this zone builds mitochondria in slow twitch muscle fibers, which improves the overall endurance and speed.
Essentially, it makes the lactate line on the graph above stay horizontal for longer.
On top of that, extended easy training teaches the body to utilize fat better and builds a leaner body.
Heart rate zones – sample Zone 2 training sessions:
Professional athletes (regardless of the race distance) usually start their season with a 3-4 week training camp where they focus mostly on Zone 1 & 2 training. Every day they would put in 5-6 hours of easy work to train the heart, focus on the form, as well as work on the base muscle strength.
- Long base-building sessions of over 90 minutes entirely in Zone 2
- Aerobic ‘maintenance’ sessions of ~30 to 90 minutes with varying intensity
Zone 3 training – aerobic endurance / marathon pace
Effort: moderate
Target heart rate: 70% – 80%
Duration: long intervals, 10 to 60 minutes
They call this zone a ‘no man’s land’.
It’s challenging enough that you feel you’re out of your comfort zone, but not challenging enough that you can’t sustain it. It’s comfortably uncomfortable.
At this point it’s barely possible to complete a sentence, before catching a breath, compared to conversational Zone 1 & 2 effort.
Many amateur athletes make the mistake of spending almost all of their training time in this zone. It ‘feels’ like you’re training hard and, indeed, athletes build quite a lot of fatigue with it.
The truth is, it does not provide enough intensity to radically improve speed or power, but is not so easy that the body is able to fully recover. So, athletes feel tired all the time, but not necessarily getting faster.
But it doesn’t have to be like that.
Zone 3 training benefits
In Zone 3 more muscle fibers are engaged and the body builds even more mitochondria in the muscles. On top of that, Zone 3 training trains the body to develop capillary network which helps to transport oxygen to working muscles more efficiently. This leads to improved muscle economy.
What this does is makes those moderate race efforts feel easier and manageable.
This builds that nice cruising speed required in longer-distance races, like half marathon, marathon or even half-Ironman triathlon.
Heart rate zones – sample Zone 3 training sessions
The key with Zone 3 training is to use interval method, instead of just maintaining it throughout the session. This approach will limit the build up of lactic acid in the body, clear the excess and will allow to tolerate more intervals.
- 3×10-30 minutes throughout a long easy session in Zones 1 or 2
- 6x6min with 6 minute recovery in Zone 1 in between
Zone 4 training – anaerobic capacity
Effort: hard
Target heart rate: 80% – 90%
Duration: longer intervals, up to 10 minutes
Zone 4 is where it gets tricky. Of all 5 heart rate zones this one is the most dangerous.
It’s at this point that most over-training happens. Inspired by professional athletes, people push themselves to the limit without giving the body enough time to recover and supercompensate. This puts a lot of stress on the body, killing mitochondria they’ve worked so hard to build.
From physiological perspective, anaerobic threshold is the point after which lactic acid starts to build up so fast that the body cannot produce enough energy to maintain the intensity for long.
Anaerobic threshold marks the middle of Zone 4 and is highly individual for every athlete.
At this point muscles get petty heavy and it’s possible to say just a couple of words at once.
Zone 4 training benefits
Training around anaerobic threshold builds power in muscles, which allows athletes to sustain very fast speed for longer. On top of that, it utilizes more muscle fibers, building mitochondria in fast twitch fibers.
Zone 4 will ‘teach’ the body to tolerate lactate better. In other words, the line on the lactate graph above will not be as steep at the end, because lactic acid will accumulate slower.
This zone is especially important for medium distance runners, kayakers and swimmers, whose race distance takes less than 4-5 minutes to complete However, endurance athletes will also benefit from this kind of training, as it improves speed and endurance.
Heart rate training zones – sample Zone 4 training sessions
This is the zone where intensity is very high and it may be tempting to go all out. The trick, however, is to avoid complete exhaustion and, instead stay within the 80% – 90% target heart rate zone.
The goal of Zone 4 training is not to run every interval at maximum speed.
Think of it as splitting a longer distance into smaller chunks and adding short recoveries in between (like splitting 5K effort into 5x1K efforts). That way you’ll be able to run every interval at speed just slightly over one you would maintain for the full distance and gradually train the body to hold it for longer. That’ called Vo2 max training session.
As this kind of training builds a lot of fatigue, my advice is to start adding Zone 4 efforts only after spending enough time on aerobic base (around 40-60 hours in total). This will help to build endurance and improve recovery speed to tolerate the effort.
- 2 sets of 4×2 minutes with 1 minute rest
- 10×1 minute with 1 minute rest
Zone 5 training – maximum effort / speed training
Effort: very hard
Target heart rate: 90% – 100%
Duration: short intervals, up to 40 seconds
Zone 5 is the ‘all-out’ effort – the maximum what muscles can produce. At this intensity massive amounts of lactic acid are produced and it’s impossible to utilize it. Muscles get so tight that an athlete is forced to slow down.
Regardless of how good the athlete is, he can only maintain his top speed for several seconds. Even 100m sprinters can maintain their top speed for only around 50m in the middle of the distance, before slowing down towards the end.
At this point the athlete is breathless – theres’s no way he is able to speak even a full word.
Zone 5 training benefits
Training in this zone focuses primarily on maximum speed. However, because maximum intensity utilizes all muscle fibers, there’s also an endurance benefit to it. If not done to complete exhaustion, this training builds mitochondria in fast twitch muscle fibers, improving athlete’s endurance.
This is why athletes incorporate drills and short pick ups to maximum speed in their sessions.
Zone 5 training is also good for practicing starts and working on reaction time.
Heart rate zones – sample Zone 5 training sessions
Maximum effort training is done mostly by time, not by heart rate. In reality, heart rate may not even jump to over 90% throughout most of the training session.
However, heart rate is a great way to check if the body has recovered from the intervals. As soon as the heart rate can’t drop to Zone 1-2 after 2-3 minutes – it’s time to end the workout.
- 5 sets of 3×20 seconds with 20 second rest
- 10×40 seconds with 2 minute rest
- 60 minute Zone 1 session with 5-10sec bursts at Zone 5 every 3-5min
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Have you had some experience with heart rate training zones already? Or are you just learning about it? Either way, share your experience in the comment section below.
What’s next?
Now that you’ve set up your heart rate zones, it’s time to sit down with the coach and create a training plan that focuses on improving your fitness and making you fitter and faster.
23 Comments
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This is best even for those who have slightly heart problem.
Hey Chris! Everyone should visit their physician regularly to be sure they can undertake an intensive training schedule. There are quite a few health problems that can have different effect on different people. But yes – I think it’s important to know how different intensities affect our body. And, generally, studies show that controlled exercise in Zone 1 and lower Zone 2 is typically good to treat many health conditions
I found your site through this article. Trying to figure out the best heart rate zone to safely concentrate on for getting back into shape. Great blog. Could you explain how your service would work? I could send you details about myself via email.
Best wishes.
Simon
Hey Simon, great to hear you like it! There isn’t one specific zone that will get you back in shape – instead, it’s a mix of them that does the magic. You can find what I offer on my coaching page – send me a note through a contact form there and let’s talk 😉
Andrejs – thanks for the great work. I am very confused because as I look at my heart rate zone training data, I am a 29 yearold male with max heartrate of (persumably) 191, but let’s say a recent easy 10k i did at 6:30min per km, my garmin 245 is showing that 95% of the run i am in zone 4 (average HR for the run was 161) – which you listed as “up to 10mins and hard intensity”. I am in a paradox of which i wonder do i
1. have a “healthy and young heart” allowing me to have a actual higher max HR hence explaining why i could stay at 161 average heart rate for a full hour? or
2. my cardiovascular system is bad that even at such moderate running pace my heart rate was so high?
looking forward to your advice!
Hey Daniel! The time I give for each of the zones is the length of the interval that would provide most optimal results (i.e. to trigger adaptations that particular zone targets). As for the heart rate, it doesn’t matter who has the higher maximum heart rate – everyone’s body is different. It’s more important to know what your zones are and control the intensity accordingly. As for the the fact that you were able to run 1h at 160bpm – to me all it says is that you put a lot of stress on the body by running a full hour around Zones 3/4. It’s definitely not an easy run. If you want my advice – slow it down to 140bpm for now and if you want intensity add a couple of 4-5 minute intervals at 160 😉
Hi Daniel,
Have you checked the HR zone definition for your Garmin? Many Garmin watches set the zones as percentage of maximum heart rate. This result in the zones being wider and having lower values than what Andrejs is showing here. What is described in this article is the Karvonen definition.
Hi – good blog posting, very clear, thanks-you.
I have a question about Zone 2 workouts that i wonder if you can answer? I’ve been training in Zone 2 for about 4 weeks and find that at some point after about half way through my workout my heart rate will spike – yesterday i ran 10 miles and at about 75minutes my heart rate spiked and then i could not get it to come down and stay down at all (https://www.strava.com/activities/4051994093/overview).
A similar thing happened on my 5 miler today. Is this part of training in Zone and indicative of my fitness – as in i need to keep working at it or something else? Would appreciate any guidance on this. Cheers!
Thanks for the kind words, Marcus 😉 what you observed is called cardiac drift and essentially means the body starts to fatigue as the intensity remains constant throughout the training or a race. If it’s a couple of beats (say 140 in the middle of the run to 145bpm at the end), I wouldn’t worry. But if the gap is larger then it means you’re finishing the run much harder than when you started and not anymore training in the correct zone
The provided information is so helpful to me. Thank you so much for sharing your thoughts
Hi Andrejs, nice blog! I’ve started focusing a lot more on HR training as of late and so I have one quick question. When doing Zone 4 interval training, say something like 5x1km, should my HR be hitting zone 4 in each of the five intervals or just in the last few as fatigue begins to build? I have trouble getting into zone 4 in my first few reps despite running comfortably faster than my desired pace. It would be great if I could get your opinion?
Thanks, James! Zones are there to help us understand how each intensity feels like, so that we can keep it constant throughout the entire session. In a 5x1k session you should be able to hit Zone 4 already in the first interval – it’s not a short distance after all. If you’re not doing it – you’re not getting the most of this kind of training. The trick is actually not to go too hard and slip into Zone 5.
Thanks Andrejs for the great breakdown – the information is super helpful. I have recently started running again (training for a half marathon in June) after a couple of years of inconsistent workouts. I have previously done many half marathons (last one was 4 years ago – came in at 1hr 57min), but have been in “the red” for the majority of my races. Currently I am trying to really focus on heartrate training and it is frustrating to say the least! I am almost 50, recently moved to a city with a higher elevation, and recently started on thyroid medicine (which can increase heartrate). I am barely able to run (~5.2-5.5 mph) at 4/1 run/walk intervals and keep my heartrate below 150. I wouldn’t be able to run more than a minute or so and be able to stay in zone 2. So, most of my “easy” runs are spent in zone 3 (as you stated above)! Is it just a matter of time? My max is supposedly 179, but I hit that the other day doing some intense sprint intervals. How long should I expect it to take to be able to hang out in zone 2 while running? Are most runners eventually able to accomplish that?
Hi Kimberly! The short answer is yes – if you stick with frequent and consistent low heart rate training the ‘easy’ pace will get faster. However, that requires volume and time, so if you’re doing your easy runs in zone 3 there’s a high chance it adds more fatigue than fitness. Try out the 3/2 run/walk strategy or go on longer hikes (flat or hilly terrain) and keep your heart rate under 140 for most of your workouts instead
Compliments for this informative article. You’ve put quite some effort in it.
Question though I noticed you write zone 1 is also for Long base-building sessions of 2+ hours.
What’s difference between long base building and zone 2? Like in physical terms.
I’ve used my HRR for zone2( 134-148bpm) and I always do my 1 hour zone 2 training around 140-148bpm and my long run(2+hours) at 134-140bpm. Does this mean I’m going too fast on my long runs? And what am i missing from zone 1 when I do my long run in low end zone 2?
Thanks Maurice! Some athletes who are just starting out can only maintain a true Zone 2 effort for 20-40 minutes until they start to fatigue. That is because their overall strength and stabilizing muscles are not yet developed. In these cases it’s best to do a long effort in Zone 1. If you can maintain it – keep it in Zone 2.
I used to workout with heart rate when I was a young athlete. I actually did not like it because we needed to only do a set within a target heart rate. Usually, my target heart rate was much lower than the effort that I would have put into the set than if we were listening to our body. I always felt it held me back, but now that I am older I can see how when we are younger it is harder to tell when we should back off within a tough workout. Now that I am a little wiser, but I still do not workout with a heart monitor. I have become really good at listening to my body. I’m at the point now where I just want to go at my speed each day and just enjoy being outside and moving.
Hi Andrejs
Hope this message finds you well. Great read and very interesting. I have been combing the internet and pub med and cat find the thing I am looking for. I was wondering could you recommend a book, or the papers that report on the physiological adaptions observed from training in specific zones?
hi Michael! These adaptations are resulting from body’s response to the build-up of lactate in the blood (try textbooks on exercise physiology). I summarized adaptations for each of the zones in my eBook. Alternatively, Joe Friel has written a lot about the effects and science of heart rate training in his books.
When calculating your max heart rate via step test or other max effort, do you use the sustained max or the peak max? I often have peaks for several seconds that are are 20-30 beats higher than what has been sustained during max efforts. For example: 5×5 minute max efforts, max sustained HR is 170ish, but 200ish is hit for several seconds on 1 or 2 of the set. This has left me in a quandary about calculating correct training zones. No I don’t have AFIB, I’ve had it checked.
Thank you in advance!
max HR is a peak figure. Usually it gradually increases until a point that it flattens out. If your HR during a test flattens out at 170 and then all of a sudden jumps to 200, then there might be a technology issue (chest strap issue, running under power lines, using wrist HR, etc.).
Weird – your Max HR calculator chart lists percentages for “Effort” but then your Zone descriptions use percentages for target HR. Confusing, since they don’t match.
For example, if I enter 60 for resting HR and 200 for Max HR, Zone 2 is calculated as being 144 – 158 bpm, 60-70% “Effort”; but when I go down to the actual Zone 2 description, it says “Target *heart rate* (not ‘effort’): 60% – 70%” — these are not the same! 60-70% of a 200 bpm Max HR is 120-140, which actually falls within the Zone 1 range of the calculated chart. Something here needs a revision.
hey Justin,
thanks for the comment and indeed valid point. Often coaches prescribe intensity in effort (like train at 70%), so I referred to that here. The target heart rate doesn’t mean you multiply your max HR with % – that’s a common mistake and doesn’t take the individual physiology into account (reflected in resting hR). The target heart rate is calculated using both max HR and rest HR with a ‘Karvonen formula’ (I share the process in this post).