The Run-Smarter Guide to Heart Rate Training

Wondering how to train smarter to get faster, improve recovery, and run more efficiently? Check out this guide to heart rate training for runners...

You may have come across buzzwords like:

• "Zone 2 Running"
• "Low-heart rate training" 

Or maybe you’ve noticed one of your favorite athletes sporting an armband heart rate monitor at the Olympic trials or crossing the finish line at the Boston Marathon.
.
Yes?
.
The use of heart rate for training is no longer limited to elite runners—it has gained popularity among influencers on social media and casual runners alike.
.
💓With heart rate monitors becoming more accessible, affordable, and accurate, any runner can choose to incorporate heart rate training into their routine. 
.
👉But is it the right choice for you?

In this article, we will delve into the world of heart rate training for runners. 
.
We'll explore:

• What it entails
• Why and how to use it, and ultimately...
• How to determine if it aligns with your goals and preferences

Ready to learn how to run smarter, not harder with heart rate training?

Simply put, heart rate training is:

• the practice of using specific heart rate zones to guide the intensity and duration of workouts to improve fitness and performance. 

✅By targeting the different heart rate zones in the appropriate way in training, you can become more efficient and able to move faster for longer–exactly what every runner wants!
.
Heart rate training contrasts with other methods like using Rate of Perceived Exertion (RPE) in that it offers objective rather than subjective data.
.
📉As a result, heart rate training makes it easy to track progress over time.

• A lower heart rate for a given pace is a solid indicator of fitness gains. 
• When compared to using specific pace windows that are determined by race times, heart rate provides more regular feedback during training.

💓By monitoring your heart rate during training, you’re able to better understand how much stress you’re putting on your body while running. 

• This is because heart rate acts as a proxy for training intensity; generally, higher heart rates equate to greater exertion and stress. 
• This is crucial for athletes who log a lot of training volume–hello, triathletes, ultrarunners, and marathoners! 
• By keeping track of your intensity, you can reduce the likelihood of injuries, overtraining, and even performance plateaus. 

🔥Heart rate also relates to what fuel your body is using as its primary source of fuel during exercise. 

• Your body is always burning fats and carbohydrates (and small quantities of protein) as fuel, but higher intensity exercise demands proportionally more from quick-burning carbohydrates. 
• Lower intensity exercise requires fewer carbohydrates and relies more on fat for fuel. 
• Since the human body can only store a small amount of carbohydrates (in the form of glycogen) compared to fat, we’re limited as to how long we can work at those carbohydrate-demanding intensities. 

That's why we should fuel with carbohydrates during longer races. Monitoring heart rate helps you understand and explore the most suitable effort zones for your running goals.
.
While these reasons for tracking heart rate are compelling for many athletes, the approach is not necessarily for everyone. 

✅Heart rate training might be a good fit for you if…

• You’ve been running for awhile and you’re ready to take your fitness to the next level
• You have a specific goal in mind (that might revolve around a PR) and plenty of time to train for it
• You’re a beginner runner who has the time to commit to training and wants to have accountability
• You’re a runner who can’t seem to strike the right balance of training and often find yourself getting injured or overtrained
• Are a runner who struggles with understanding your own perceived effort

❌On the other hand, it might be a poor fit if you…

• Are an extremely time-limited athlete who runs low volume
• Just want to have fun with running and enjoy your miles 
• Are a beginner who is just starting to string together a few miles without stopping

😭The often-frustrating reality is that when you begin using heart rate to monitor intensity...

• You will probably find that you need to slow down–particularly on your easy runs in zones 1 and 2. 
• Aerobic development takes time; it’s not a game of days and weeks, but rather months and years. 
• Your fitness improvements won’t be dramatic overnight changes, and training response will vary from person to person.
• But you might start to notice your heart rate getting a bit lower for the same paces after a couple of months.

If this all sounds too tedious for your goals, you’re not alone!

• Many runners forgo the complexities of heart rate training in favor of using RPE (common in trail and ultra) or pacing (most common with road runners). 

However, if you feel that heart rate training could be a good fit for your running journey, read on to find out how to customize your heart rate zones to your unique physiology. 👇

When choosing a heart rate monitor, the chest strap has the most accuracy, but they can be uncomfortable. Many athletes are now using armbands. 

In order to make sure your heart rate measurements are accurate, you will want to use a heart rate monitor chest strap or armband. 

• 🚫Your wrist-based heart rate from the optical sensor in your GPS watch is likely inaccurate and especially faulty if you’re running fast on technical terrain or if you’re running in extreme temperatures. 

👍WeeViewers recommend the following heart rate monitors:

• ✅GarminHRM Pro
• ✅Polar H10
• ✅Polar Verity Sense
• ✅Wahoo Tikr Fit
• ✅Myzone

Quite often, heart rate zones are determined by your maximum heart rate:

• 🟰 the greatest number of beats per minute your heart can pump under maximum stress. 

Every person has a different maximum heart rate. It's highly impacted by factors such as:

• Age
• Genetics
• Fitness
• Altitude
• Stress, and...
• Medication 

For heart rate zones based on maximum heart rate, each zone is a fraction of the max heart rate.
.
If you want to get a rough estimation of your maximum heart rate, you can use the general equation of:

• Maximum Heart Rate = 220 - Your Age

However, this equation tends to overestimate for females and underestimate for males.
.
There are other mathematical formulas that exist for calculating maximum heart rate, but they have large margins of error–at least 10-12 beats per minute.
.
While the golden standard for finding max heart rate is a graded maximal exercise test in a lab, you can do your own testing with a heart rate monitor to get a close estimation.
.
💓DIY methods for testing your maximum heart rate:

• Polar’s uphill field test
• Marathon Handbook’s 100m sprint and ramp up field tests
• For experienced runners who might struggle to dig deep in a field test to achieve maximum heart rate, an all-out 5K race can work too, but the field tests listed above are a better bet.

Maximum heart rate is not the only physiological marker you can use to pinpoint where your heart rate zones are. 
.
You can opt to find your aerobic and anaerobic thresholds in place of maximum heart rate or in addition to it. 

• Aerobic Threshold: the heart rate at which your body begins to demand more from carbohydrates as fuel instead of fat. Paces and efforts below your aerobic threshold are sustainable for long periods of time.
• Anaerobic Threshold: the heart rate at which your body is producing more lactate than it can clear. Once you tip over your anaerobic threshold, byproducts of lactate begin to accumulate and you’ll begin to experience fatigue. Running at this intensity requires exponentially more recovery time than lower intensity and too much time here can actually negatively impact your endurance. 

Note: For the purposes of training, your anaerobic threshold is the same as your lactate threshold.
.
✅How to estimate your aerobic threshold heart rate: 

• Maximal Aerobic Function (MAF) Calculation: as the first “quick and dirty” estimation, all you have to do is subtract your age from 180. Your result is the top of your zone 2 in the 4 and 5 zone models. 
• To further refine the MAF calculation:
  • Add 5 bpm if you have been training consistently for more than 2 years and have been seeing improvements. 
  • Subtract 5 bpm if you’ve been training inconsistently or have been injured or sick
  • Subtract 10 bpm if you’re recovering from major illness 
• If you want to take things further with a field test, check out the other aerobic threshold testing protocols from Uphill Athlete.

✅How to estimate your anaerobic threshold AKA lactate threshold (top of zone 3 in the 4 and 5-zone models):
.
You can find your anaerobic threshold by performing a 30-60 minute race effort and wearing a heart rate monitor. 

• Beginners should opt for the 30-minute effort while more advanced runners should perform the full 60. Y
• our average heart rate for the race effort is a decent estimation of your anaerobic threshold, or lactate threshold heart rate. 

Here's a good one: Uphill Athlete Heart Rate Zones Calculator 
.

• You’ll probably notice that many different heart rate zone models exist including, but not limited to the 7, 5, 4, and 3 zone models. 
• Most watches will use the 5-zone model. 
• The different models strive to provide more granularity with data, but not all runners will need (or want) that much complexity. 

There are three primary ways that heart rate zones in the models are determined: 

1. Percentage of maximum heart rate
2. Percentage of lactate threshold heart rate
3. Heart rate reserve 

👉TIP: If you aren’t sure which model is best for you, check out Coros’ Ultimate Guide to Heart Rate Zones.
.
Inspired by fluidathletics.com’s version, below is an attempt to simplify some of the common heart rate zone models and terms we see associated with them, including energy contribution and time to failure. 

While all of these zones can be informative for training, it’s important to realize that each of the zones are estimations, not infallible truths.

• Keep in mind, our human physiology doesn’t exist within discrete numerical boundaries.
• Additionally, your heart rate zones are not fixed values. They will shift in response to external and internal stimuli. Over time, and as you gain fitness, they’ll also change. 

💓1. Hydration

• Dehydration will elevate your heart rate because of reduced blood volume, body temperature increases, and electrolyte imbalances. 

💓2. Stress

• When the sympathetic nervous system is stimulated by stress, your heart rate increases

💓3. Medications
 

• Stimulants, diuretics, antidepressants, thyroid meds, asthma meds, and decongestants can all increase heart rate. Calcium channel blockers and beta blockers can depress heart rate. 

💓4. Menstrual cycle

• For those who menstruate, resting heart rate is often lower in the follicular phase and higher in the luteal phase. The hormonal phases can also impact exercising heart rate and RPE.

💓5. Altitude

• Higher altitude depresses your maximum heart rate, yet will be generally higher for a given exercise intensity.

💓6. Heat

• Running in heat can elevate the heart rate by 5-10 beats per minute at a given effort, so zone 2 might look more like zone 3

💓7. Age

• As we age, our maximum heart rate decreases 

💓8. Fitness

• With greater fitness, our aerobic threshold heart rate and our anaerobic threshold heart rate can increase. Well-trained athletes can have an aerobic threshold that is within 10% of their anaerobic threshold. 

After a stressful day at work, you go for a recovery run on a hot and muggy afternoon...

• Although you’re running the same route as you did last week on one of your days off, your heart rate is 8 beats per minute higher for the same pace. 
• No, you’re not suddenly out of shape. 
• Stress and heat create the perfect storm for an elevated heart rate. 

Since the goal of this session is to recover, you’ll likely have to slow your pace to keep your heart rate in your recovery zone. 
.
On paper, heart rate training might seem pretty black and white, but in reality, it’s a dynamic, nuanced system that serves as a training tool–not a set of hard and fast laws. 

Once you’ve purchased an accurate heart rate monitor, established your heart rate zones, and input them into your GPS watch, you’re ready to train!
.
As with any new training intervention, consult your healthcare professional team to make sure you’re safe to proceed.
.
The following phases are general suggestions, and your heart rate training journey may look different. 

Run a large portion of your weekly volume in your aerobic zones–at or below your aerobic threshold heart rate.
.
TIP: Including quick bursts of speed like strides on a zone 2 run can be highly beneficial since they support speed development without producing a ton of lactate or compromising recovery. 

• This phase will prepare your body to better handle the rigors of higher intensity training, and indeed, get more out of them.  
• *Strides are short enough that they might hardly budge the heart rate, but if they do, simply run easy enough after each stride so your heart rate falls back into the aerobic zone”
• If you’re already coming into heart rate training with a strong endurance background, sprinkle in your workouts as usual.

Once you’ve grown accustomed to using your heart rate monitor and you understand your limits with running volume, you can experiment with introducing workouts above your aerobic threshold 1-2x per week.
.
Workouts that have you running above your anaerobic threshold are quite taxing on the body and shouldn’t be done more than 1x per week for most runners.
.
The smartest move for sub-elite runners is to only change one variable at a time...
.
Meaning that though you can increase running volume OR intensity in a given week, you should not increase both in a single week.  

• Also note that unless you’re a high level runner or have an incredible capacity to recover from anaerobic training, most training should be under your anaerobic threshold. 
• If you were using RPE it would be “fun hard”. Like Arthur Lydiard, one of the more successful and respected coaches of all time, said “train, don’t strain”.

• Use recovery activities and rest days to make sure that you’re adapting to the training
• Monitoring resting heart rate can be useful for understanding your recovery status.

If you’re doing more work than you have previously, you’re tired, and not getting faster, you might be doing too much and/or running too hard. 

• Take a week or two at an even lower heart rate then tackle a workout again and see if that’s what your body needs.

Without seeing notable progress in a training plan, no runner would (or should) stick with it. Heart rate training is no exception.

Once you’ve been consistently using heart rate to monitor your intensity for 4-8 weeks...

•  You should start to see slightly lower heart rates for the same paces. 
• You can confirm the fitness progression by retesting your aerobic threshold heart rate regularly. 
• Because the test for your anaerobic threshold requires race-like effort, you probably won’t want to test that as frequently. 

If you commit to heart rate training for long enough...

• You’ll probably start to notice your pace in your zone 2 will become quite fast–perhaps even tiring! 
• That’s the signal to shift your easy runs from targeting zone 2 to instead targeting zone 1. 
• As athletes reach greater aerobic fitness, their aerobic threshold is so high that their neuromuscular system experiences greater stress than their cardiovascular system, putting them at risk for injury with too much zone 2 running. 

While zone 2 running holds plenty of benefits for less-trained runners, we also can’t neglect the work to be done in the other zones! 

• Performing tempo runs and lactate threshold intervals in zone 3 along with the intermittent speed stimulus from working at/above your anaerobic threshold will all contribute to greater long-term running development. 
• Monitoring your progress at your top end, you’ll start to notice that you can run for longer at higher heart rates. 

• To establish your personalized zones, you’ll want to use a reliable heart rate monitor. Your wrist-based heart rate readings from your optical sensor in your GPS watch are likely inaccurate.
• Heart rate is impacted by your environment (altitude, heat, etc.), lifestyle (medications, hydration, menstrual cycle, etc.), and genetics. 
• You can determine your personalized heart rate zones by finding your maximum heart rate, aerobic threshold heart rate, and anaerobic threshold heart rate. 
• Your aerobic threshold heart rate likely corresponds with the top of your zone 3 in a 5 zone model if you’re using % lactate threshold.
• Your anaerobic threshold heart rate, or lactate threshold heart rate, corresponds with the top of your zone 4 in a 5 zone model if you’re using % lactate threshold.
• Aerobic development takes a long time—think months and years rather than days and weeks. Speed and lactate threshold develops on a quicker timeline (weeks).
• Solely focusing on easy running–also coined “zone 2 running”–will not produce better performances. A well-balanced training program will target high and low intensity in the right proportions for you. 
• Heart rate training is not ideal for every runner, and that’s ok! 
• Readjust your zones to account for fitness gains and/or life changes
• Highly-trained athletes will do a greater amount of their easy training in zone 1 (in the 5 zone models) while less trained athletes will run in zone 2 more frequently on easy runs. This is because highly-trained athletes are actually running quite fast in zone 2, meaning that they’d be at greater risk for injury if they did too much in zone 2. 

 If you’re curious about implementing heart rate training, drop your questions and/or thoughts below!