What Heart Rate Tells You About Your Workout: Is Your Heart Going To Explode?

Let’s talk about our hearts today. Hopefully it’s beating happy and healthy and you’re feeling alive.


While that’s all important, it’s not what I want to chat about.

I recently received this email from one of my closest friends

I Picture My Heart Exploding At Some Point


“I’ve been working out with my HRM for a while and I have a good feeling of what exertion level is associated with a range of HR’s (heart rates), for example when I’m dying I’m usually at 165…My max HR for my age is in the range of 175 to 180 depending on the formula.I’ve noticed though that when I am running I am constantly at 160 – 165 which is totally anaerobic.

Does this mean that I’m out of shape?

How is it possible that I can run for 30 minutes at near my max heart rate?

I picture my heart exploding at some point and I’d rather just not run with the HR Monitor because it messes with my head.

Am I really dying or am I just seeing that I’m dying and letting my mind mess with me?

I do find myself having to stop during the runs and take breathers for 10 seconds or so, but that doesn’t really offer me much recovery to do another .5 to 1 miles until I have to stop again…

Please explain!”

Well, okay.

So that’s where we are today because I feel like a ton of people use heart rate monitors but don’t really know what it means aside that it says your heart is beating.

What Is Maximum Heart Rate?

And no, it’s not how fast your heart beats when you kiss your guy!


First things first…

Your maximum heart rate is the highest your heart can beat safely… it’s the “threshold” of where you can take yourself if you were to go full out 100% with your workout.

Everyone’s max heart rate is different depending on age, fitness level, overall health and a slew of other variables. But for the most part, it’s pretty easy to get a rough estimate.

If you’re under 40…Max HR = 220 – Age

If you’re over 40, the best equation to use is:

Max HR = 208 – (.7 x Age)

So for me (I’m 30)… my MHR would be 190 beats.

Once you know your Max Heart Rate, you’re able to use the heart rate monitor to hit certain training perameters to accomplish desired training results.

The HR Monitor Is The Best Fitness Tracker!


Heart rate monitors were the first high tech fitness trackers, no? Okay, maybe after pedometers.

But out of all trackers, I think they’re the most useful in terms of the information they can give about you, your fitness levels, and your workouts.

Sure knowing how many steps you take in a day is useful, it helps motivate you to move more. But for those of you that already love exercise, and really don’t need help moving more throughout the day, they are a waste of money (sorry, it’s true).

But in terms of…

Improving Fitness And Overall Health… Using a Heart Rate Monitor Can Help Tremendously!

After all, if you ask people when they are working out to identify the intensity of their workout, they will likely be wrong.

A study by York University proved it by discovering that most people will overestimate exercise intensity… meaning they workout below the level they should.

Having a heart rate monitor can make it easy for you so you know when you’re exercising and when you’re wasting your time.

That is, if you know how to use it (beyond putting on that comfortable strap and plugging your information into the system).


Heart Rate Zones

Now that you know your MHR (Max Heart Rate), you can use that to determine all the other fitness zones.

You’ve heard words like “fat burning zone” and “anaerobic zone” but what does that mean?

Let’s break it down…

Why? Because I freaking love science and talking stuff like this!

Fat Burning Zone… Long & Easy
  • 60-70% of your MHR
  • This zone improves your hearts ability to pump blood and enhances your muscle’s power to use/take in oxygen.
  • The increased oxygen to muscles, allow them to recover, making this a great zone for recovery runs, long runs or easy workouts.
  • The body learns to metabolize fat as a fuel.

Going back to using myself as the case study, my heart rate would be between 114 – 133 beats/minute.

Don’t worry, in just a second we’ll go over why and when we should train here. But I think it is important to stress that while the percentage of fat burned is high, this doesn’t mean if you are trying to burn fat where you should stay.

The harder you exert yourself, the more calories you burn.



Some may come from carbohydrates being broken down, some from fat… but regardless the best way to lose weight is to burn more calories than you take in. Create a deficit!

My point…

Don’t let the “fat burning zone’ tempt you to do all your training here. You get much more bang for your time buck in other zones. Got me?

Aerobic Zone… Target Heart Rate
  • 70-80% of your MHR
  • This zone is the most helpful for improving your overall cardio health and fitness. If you want to be able to run farther, longer than this is the place you’ll want to spend a lot of time.
  • Your body is able to increase it’s cardio-respiratory capacity, that’s just fancy jargon for saying your body’s ability to transport oxygen to the muscles and take away carbon dioxide.
  • Helps to condition the muscles as well.

For zone 2, my heart rate would be between 134 – 152. <— Just to give some perspective.

This is the zone where you will likely find yourself in most often when doing cardio workouts, or workouts at FitWomensWeekly.

Or at least, it should be.

Anaerobic Zone: Lactic Threshold

The anaerobic state is the zone that Jeanette is finding herself in during her runs.

  • 80-90% of your MHR
  • During this zone the body cannot remove lactic acid (byproduct of the muscles) as quickly as it’s produced. Have you ever experienced itchy legs during a run?That’s lactic acid… I used to get it ALL the time and that was my sign that I should slow down a bit.
  • Training here is actually important as it helps to increase your lactic threshold… if you can hold it here for a long time, that’s impressive as you’ll feel tired, and find yourself breathing hard.
  • But this will help to improve your overall physical performance… if you’re aiming to improve.

For the anaerobic zone, my heart rate would be between 153 – 171. <— Getting close to my Max!

Red Line Zone: VO2 Max

This zone should only be reached by those of you that are fit… really fit. It’s intense, it’s hard to recover from and it will leave you feeling as if your chest is literally going to explode.

  • 90-100% of your MHR
  • Should only be hit for very short spurts.
  • Amazing at increasing your fast twitch muscle fibers and developing speed.

I personally train in this zone every week… so it’s not something to be afraid of. But more on that in just a second, hang on tight!

For me, my heart rate jumps between 171-190 beats in this zone. And it’s killer! Killer awesome.

Why Train In Different Zones?


Training between all of the zones is really important for your overall physical fitness, mind and body composition.

If you’re looking to burn body fat, then keeping all of your workouts within the first 2 zones is possible but for your overall health, it’s important to bring your heart rate up and down.

Plus, playing around with intervals (going way up in heart rate and rest to bring it down before going up again) can burn a tremendous amount of body fat fast! It’s the training system I use when I want to lean out quickly.

The demand is puts on your body is huge!

“The study by Jason Talanian, a PhD student in the Department of Human Health and Nutritional Sciences, was published recently in the Journal of Applied Physiology.

It found that after interval training, the amount of fat burned in an hour of continuous moderate cycling increased by 36 per cent and cardiovascular fitness increased by 13 per cent…

It did not matter how fit the subjects were before. After interval training, they experienced not only an increase in fat used and in aerobic capacity, but also an increase of enzyme activity in the muscle.” – Source

But let’s get a bit more specific.

Fat Burning Zone

Slow and steady workouts are important to help the body recover. The increased oxygen actually helps muscles to recover from previous workouts. Enjoy a light cardio session after intense, hard workouts.

They don’t have to be long, just 20-30 minutes.

This is also the zone for long runs, which because of their length should only be done 1-2 times per week. These long runs help to build strength, endurance and helps to burn some serious calories!

Basically, it’s prolonged recovery run in terms of speed.

Just remember, just because it has the “fat burning” label, doesn’t mean that you’re going to burn the most amount of fat. Think about how many calories you burn jogging 2 miles… you’re talking maybe between 170-200 depending on how great of shape you’re in.

But if you full out run as fast as you can for 2 miles (stopping to rest when needed) you can burn up to 20 calories a minute!

Thats a total caloric burn of 250+.  Speed work… does a body good!


Working out here will help to improve your body’s ability to use up available oxygen to use carbs and fat to fuel.

For training purposes, you should aim to train here 2-3 times per week. That could be with cardio sprints, workouts with FitWomensWeekly or great strength training sessions.

Just make sure to give yourself time to recover (most people need 48 hours).

VO2 Max

Oh sprinting, how I love you!

For those of you that have been exercising regularly and consider yourself in shape… are you adding sprints into your workouts?

You should!

Training here will help to increase speed, power, and muscle.

Just look at a sprinter to see the awesome benefits for the body.

But this zone is hard, and shouldn’t be done more than 1-2 times in a week.

If we were to talk about my training, then I would tell you that every Tuesday morning you can find me at a local track knocking out sprints.

They are hard, they burn, but they will make you an overall better athlete and helps tremendously with body composition!

What Does It Mean When You’re Heart Is Racing More Than It Should?


So let’s go back to Jeanette’s email…

Using the information above, it’s now a no brainer.

She needs to slow the heck down.

I know and she knows that she can run 4 miles in an anaerobic state (because she’s in great shape) but that doesn’t mean she should if she wants to improve.

Just because you can, doesn’t mean you need to go balls to the wall with every run (sorry I hate that expression but it works too well).

I Would Recommend She Slows Down To Get Into Her Target Zone

Will she feel slow?

Probably, but by practicing following her heart rate instead of the speed at which her feet can carry her, she will improve. And my guess is, improve quickly.

She will notice that her pace will be able to creep up yet she will be able to maintain that lower heart rate.

And that’s the power of using the monitor.

Having actual data right there to help guide your training efforts.

Does all this make sense?

I hope so, but I understand that science and math can be confusing, especially when you put them together!

So if you have any questions, do not hesitate to ask below, and I’ll be more than happy to go even deeper.

There Are People Who Know More Than Me – Shocking I Know 🙂

While I know about heart rate training, and I think it’s an awesome way to help monitor improvements and assist with training, I don’t personally use it.

I should and I have every intention of picking up a strap to use with my Garmin.

But since I don’t have one, you should seek more information and help from people who do.

I happen to have several friends who I classify as “HR Pros” that can offer a ton of advice:

The Two Amandas:

Amanda @ Run To The Finish

Low Heart Rate Training

Maffetone Heart Rate Training

Amanda @ MissZippy

The Best Training You’re Not Doing

Summer Of MAF

Browse their training posts for some great tips!

So of course now I have to ask…

Do you use a heart rate monitor… and really use the data it spits out?


  • I don’t use a heart rate monitor, but I like how you broke this down and explained it because it is so true about running slower. I try to use group runs for that because nobody is out trying to go blazing fast in a group run (lol), but different workouts are good for training different distances. Looking back on last year, I think I did too much anaerobic/Vo2 max/LT stuff before my marathon and that hurt me because I wasn’t really slow on my runs except my long run- because I did it with people. I should have maybe done more fat burning or aerobic workouts. Even now, I’m always running my easy runs too fast!

    And I freaking love science too :).

    Great workout w/ you and Katie today, feels so good to be back! Glad to be running fast again :).

    • It was great to see you back! You were on fire! Great work.

      Yes, we are notorious for running too fast for all our runs! Gotta swallow some speed pride and slow down some times!

  • Eveliz

    I don’t and I’m afraid that if I did it would have the same effect on me as counting calories – making me obssessed and crazy lol.

    • Def a tool for some but not for everyone! I can relate, definitely not worth becoming obsessed with if you know your body!

  • Ronda Kaye ;)

    Excellent article Taylor! My calculated HRM max is 178 and I am easily at 190-200 in any type of high intensity session. Heck when I’m just lifting weights (heavy, but not speedy) I am at 165-170. And I spend a lot of my workout time there lately 🙁 I am one of the rare people who probably underestimate excercise intensity. I’m going to wear my monitor more now and really watch those numbers.

    • Thank you Ronda! Def watch those numbers, and see if you can keep it under your max more often!

  • I have a hard time not running at 80-90% of my MHR. But I’m not a fast runner and am not going balls to the wall. Running is just hard for me. Is that still okay?

    • It is fine, I think it also depends on how much you run. If you’re running 6 days of the week like this, it might be a bit much and I would recommend taking a day or two to just go for a power walk or jog. But if you’re giving yourself rest days then you’re golden!

  • Brittany

    Great post! I think it is so important to reflect on our workouts and on improvement while also recognizing that training across the spectrum of HR is also important. It’s easy to think that every workout needs to be a hard HR workout, but just like varying activity and muscle groups when lifting, varying our HR’s make us better athletes overall. Thanks for sharing. The graphics are awesome as well!

    • Thanks Brittany! Exactly, changing things up is key for a total package fitness program.

  • Jeanette

    I will be wearing mine tonight for our KB workout. Thanks for showing the love with the blog post :). Great way to break it down! Now I’m thinking I should get the adapter for my watch so that I can see all of the details of my workout and not just my average HR.

    • it would def. do more if you knew exact rate and not average!

  • I use a heart rate monitor but also since it gets annoying with longer runs I use the talk test (especially on long marathon training runs) if I can hold a conversation then I am at the right speed for distance training. I have a pretty low HR in general (resting is in the 40-low 50’s range) so reaching that top HR zone is HARD for me. I rarely can get to or over 170 even doing interval workouts. I appreciate the data but there are so many factors that play in especially dehydration elevating HR that while it’s useful tool (and good to go back and repeat runs to see how your fitness has improved) I’m not a slave to it.

    • Gianna, I am the same. I don’t personally use one either. I understand the benefits and how some people would do better with one, but like you I know my body and my heart is in the low 50s too. My husband always makes fun of me, i just rub it in his face that I’m in better shape 😉

  • Sheena

    This is interesting, I thought just running hard was the best way to improve! Now I want to try it 🙂

    • It’s def fun and interesting to play around and see how your body reacts!

      • Sheena

        I wonder if I can get a strap that talks to my phone, I usually bring that along with me for some tunes to jam with on my run.

        • I am sure there is an ap for that!

  • LOL! OMG I can just imagine someone’s excuse for not working out: My heart is going to explode if I work out!! It makes this really weird feeling when I do anything strenuous. AH HA! No… Your heart LIKES IT!

    • bahaha. trust me, I hear it all! people are crazy!

  • Sarah Osterman

    I love my heart rate monitor and seeing how hard I am working. And the bonus is the calories I burn. Thanks for breaking it down. That helps a lot.

  • Heather

    I use mine for the calories. I love seeing what I’ve burned. I have noticed that my HR has been lower from when I started bootcamp, so that’s something 🙂 good read!

    • That’s awesome that you’ve noticed that! You’re such a beast!

  • Pingback: Friday Finisher 8/8/14 | Strength and Sunshine()

  • Pingback: Link Love #48 | Barr & Table()

Pin It on Pinterest

Share This