What to Expect from Heart Rate Zone Training

Last Updated on October 31, 2017 by Heather Hart, ACSM EP-C

Many, many, years ago, I was a newer runner with very big goals.  I decided to hire a running coach to help me achieve said goals.  The very first thing coach had me do was a lactate threshold test (which I conveniently got to do in the form of a fancy VO2 max test in an exercise science lab, perks of being a university student at the time) and then, I was assigned running “zones” based on heart rate instead of pace.

I will never forget the very first workout in an assigned heart rate zone.   Coach asked me to stay in Zone 2, and to try my best to not go into Zone 3.  Sure, I thought, how hard could that be?  I hopped on the treadmill at my community gym and went to work.  I ran at what I perceived to be an “easy” pace.  Yet…my heart rate was much higher than it was supposed to be.  I tried to slow down: heart rate still too high.  I slowed down my running pace even more, and was still a few beats per minute above what coach wanted me to run.  In my mind I thought “this guy is crazy, I’m running at a snails pace, how am I ever going to get FASTER doing this?” and continued on my run at what I perceived to be “easy but acceptable” pace.

That night I checked in with my coach, who asked how the run went. I told him it was near impossible to keep my heart rate in that zone without walking.  He replied “then you walk.”

The next few weeks of  training were an incredibly frustrating, humbling experience of me trying to keep every run in the appropriate zone.  I still did not believe that this training was doing anything but making me slower.  After all, in my new runner mind faster training runs = faster race times.  You have to constantly push HARDER in order to get BETTER, right?

Wrong.

Unfortunately, due to an unrelated injury, I parted ways with my coach, and never had the opportunity to see my heart rate zone training efforts pay off at the time.

Fast forward to many, many years later, and I’ve finally found the discipline to follow a heart rate zone training plan for nearly a year now.  The results, for me as a new ultra distance runner trying to build a solid endurance base, have been incredible.  The results of many of my clients that have stuck with heart rate training have also been incredible, with distance and pace PR’s aplenty.   So why do I even tell you the above story about how much I hated heart rate zone training at first?

To demonstrate that without a shadow of a doubt, I get it: heart rate zone training can be one heck of a frustrating process in the beginning.

So why do we even bother?  Well let’s get to the nitty-gritty of it.

WHY HEART RATE BASED ZONE TRAINING?

There are a number of reasons to use heart rate based zone training, and endless, in depth explanations available online. For the sake of brevity, which is not something I’m normally capable of, and for the sake of not confusing readers, I’ll share the two main reasons I prefer to use heart rate zone training for clients who are looking to build endurance as they step up their race distances:

1) It helps prevent burnout and injury.   Many runners tend to push higher intensity training, and not even realize it, more frequently than they should.  This can lead to physical and mental burnout, and even worse, potentially injury.  Giving our body the opportunity to recover when necessary is invaluable, and using heart rate zones can hold us accountable to truly keeping it “easy”.

On the other hand, I’ve worked with a number of runners who were often too nervous to push out of their “comfort zone”, and never pushed as hard as they should on harder effort days, such as tempo runs or speed work.   Again, heart rate zones keep us accountable.

Now, I don’t believe in “junk miles” in the traditional sense.  But I do believe the importance of going easy on easy days, and hard on hard days.  Heart rate zone training allows us to read our body’s true effort…and how well it is recovering…much more accurately than “perceived exertion”, which is highly subjective.

2) Each zone has a purpose.  While there is not a light switch that flips when you transition from one zone to another, each general zone has a different purpose.   These are VERY general explanations, without going into potentially confusing exercise physiology talk:

Z1: (Light zone)  Perfect for true recovery runs.  Allows increased blood flow to muscles to aid in recovery, but does not put significant stress on the body.

Z2: (Easy zone) Fat oxidization (using stored fat for fuel), capillary building, building a solid endurance base….this is essentially where you become better at running slow miles for a long time.

Z3:  (Moderate zone) Improve efficiency of blood circulation, begin training body to process lactic acid.

Z4: (Hard zone) Carbohydrate utilization, teaching body to withstand higher levels of lactic acid build up.  This is where you learn to push through the muscular fatigue that comes with running harder and faster.

Z5: (Maximal effort) Typically short bursts of high intensity exercises, useful for recruiting and training fast twitch muscle fibers (i.e. the opposite of the long, slow, running mentioned above).  This zone should be used purposefully and sparingly, in order to avoid injury.

By using heart rate zones, we can try to more closely target the physiological adaptations we are hoping to achieve with each specific workout.

Screenshots from friend’s Garmin Connect accounts showing time spent in each heart rate zone. I have no idea what the goals of these workouts were, but they demonstrate how heart rate can easily be split into “zones” on modern GPS and heart rate monitoring devices.

WHAT YOU CAN EXPECT…AT FIRST.

You might discover that what you previously thought was your “easy” pace is not as “easy” as it needs to be.   Alternatively, you might discover that you aren’t pushing on your hard enough on your harder effort days, such as tempo runs or speed work.  You may find that you are doing the majority of your runs at a heart rate effort that falls between the zones often called for by your coach.

As such, you might become frustrated.  If you are anything like most runners (former self included) you might find yourself falling into your base building heart rate zones (typically Z1/Z2) at a pace slower than what you are used to, and slower than what you know you are “capable” of.  Runners very often tend to get caught up in numbers, taking pride in faster paces, or feeling ashamed of slower paces.   These feelings are normal, but I encourage you to push them aside.  Remember that the long term benefits of “slowing down to speed up” will pay off in the end.   Running, after all, is a LIFETIME sport.

WHAT YOU CAN EXPECT…LONG TERM. 

When done properly, you can expect that your paces in a particular zone become faster over time.  In other words, you are running faster and farther with less effort.  So we are not simply teaching our bodies to be able to “suck it up and push faster and/or harder”, but instead, we are training our bodies to become more efficient.  And what runner doesn’t want their current “fast” pace to one day be their “easy” pace?

WHO MIGHT NOT BE A CANDIDATE FOR HEART RATE ZONE TRAINING.

• Runners who have a variable heart rate due to things like a pre-existing cardiac issue.
• Runners who may be on a medication that directly affects heart rate.
• Runners who cannot get a reliable reading from heart rate monitors, due to monitor placement or fit.
• Runners who simply cannot run in prescribed zone, and must walk 100% of the time (this defeats the purpose of run-training)
• Runner’s who can’t get an accurate lactate threshold heart rate test, for whatever reason.

These are just a few examples of who may not be a good candidate for heart rate training.  In these cases, I prefer to go back to setting our zones based on prescribed pace and self perceived effort, rather than heart rate.

TIPS TO GET THROUGH THE BEGINNING STAGES OF HEART RATE ZONE TRAINING.

1) Remember that your coach has carefully planned out your training plan.  If you are currently in a monotonous phase of constant Z1/Z2 training, know that this will not last forever.   There is a reason for focusing on the “slow” for a while, just as there are reasons for higher tempo “fast” runs.

2) If you are one who is obsessed with pace, set your GPS screen to show heart rate ONLY.  Don’t worry about pace, don’t worry about distance.  Turn your focus instead to seeing how well you can keep your heart rate in it’s prescribed zone.

3) Know that heart rate is variable, where as prescribed pace is stagnant.  Changes in stress level, health (i.e. sickness), hydration status, or even menstrual cycle can affect heart rate.  Further, external factors such as temperature, air condition, etc. can affect heart rate.  Therefore, on a day you “aren’t quite feeling yourself” or even really hot, humid days you may notice you are running at a slower pace in your prescribed one.   On days where the weather is crisp and cool, you are well rested and hydrated, you may feel like you are effortlessly flying while staying in your zone.  What this means for you is that by staying in your zones you will not be pushing TOO hard on days when your body is clearly telling you that it is already under stress.

4) Trust in your training. I cannot emphasize this enough.  In my experience it takes a solid 4-6 weeks of training using the heart rate zone method to begin to notice improvements.  At that point, you truly see the value of this type of training, and you’ll be very happy you stuck with it!

5) Give yourself “free run” days.  Or make sure your coach does.  Scheduling “fun run” or “free run” days into your training plan, where you run by feel and completely ignore your heart rate will help prevent training frustration and burnout.  Use these days to remember why you enjoy running in the first place.

LAST NOTE:

There are endless arguments against heart rate zone training, and some of them are certainly not without merit.  And it does not work for everyone, for a myriad of reasons.  (It should be also noted that HOW you test for your heart rate zones can have a huge correlation to how accurate your zones are.  Consult with your coach for more information. )  However, it has been my experience that most beginner to intermediate runners have been training without a lot of “purpose” and specific planning.  In these cases, heart rate zone training not only gives a specific outline to training (paired, of course, with a periodized plan written by a coach) but also teaches the runner to learn to recognize effort (i.e. “easy” vs. “moderate” vs. “hard”, etc.) with quantifiable numbers.  And further, to use their heart rate to better recognize outside factors like stress, dehydration, potential illness, etc. rather than just writing it off as a “bad run” and getting frustrated.

My goal, other than helping clients achieve their race specific goal, is to teach athletes to be better runners.  And learning to really become in-tune with your body is a HUGE part of becoming a successful runner.