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Heart Rate Monitor for Cardio Training: How to Use Heart Rate, RPE, and the Talk Test
- Emma Mattison
- 7 hours ago
- 4 min read
Heart Rate Monitor for Cardio Training: How to Use Heart Rate, RPE, and the Talk Test
So you’re making a life change. You’re starting a cardio program. You walk into the gym and think, “Okay… how often should I train, how hard should I go, and does it matter what type of cardio I choose?”
There are a lot of questions about cardio. But in my world, it boils down to one word:
Exertion
Exertion is the difference between “I’m doing cardio” and “I’m training my cardiovascular system in a way that’s safe, effective, and sustainable.”
In this article, I’m going to show you how to use three tools together:
Heart rate
Rate of Perceived Exertion (RPE)
The Talk Test
When you layer these correctly, you stop guessing and start training with intention.
Why I recommend a heart rate monitor for cardio training
If you’re following one of my pre-made programs (or you’re building your own plan), I strongly recommend using a reliable heart rate monitor for cardio training so you can see what your heart is doing in real time.
You’ll hear people debate chest strap vs. wrist-based devices. Here’s the truth: the “best” option is the one you’ll actually use consistently—but if accuracy is the priority, chest straps are often the stronger choice for many people.
Recommended tools
Heart rate monitors (to track real-time exertion):
App I recommend (to better understand recovery + readiness trends):
Heart rate zones matter, but heart rate alone is not enough
Heart rate monitors for cardio training are useful because they show your heart beats in real time, so you can see whether you’re roughly in the zone you’re aiming for (light, moderate, vigorous).
But it’s crucial that we don’t rely only on heart rate.
If you’re on certain medications, your heart rate can be misleading
Many individuals are on medications such as beta blockers, which can significantly impact their heart rate response—sometimes by 10–30 beats per minute. So if you’re only using heart rate zones, you can easily end up under-training or over-thinking what your body is doing.
That’s exactly why I teach this as a 3-part system.
Rate of Perceived Exertion (RPE): the missing skill most people never learn
RPE is your personal rating of how hard something feels.
It’s subjective, and that’s the point—because your body doesn’t care what a formula says your heart rate “should” be doing. It cares about the total stress you’re actually experiencing.
Here’s what makes RPE tricky:
If an exercise is new, it can feel harder even if the physiological demand isn’t extreme.
Two people of the same age/height/weight can have totally different “this feels hard” responses.
So we need a second anchor to keep you honest…
The Talk Test: the simplest cardio intensity tool you can use today
The Talk Test is exactly what it sounds like:
If you can sing while exercising, you’re likely in a very light intensity zone.
If you can talk comfortably, you’re generally in moderate intensity.
If you can only get out a few words, you’re pushing toward vigorous intensity.
This is one of the easiest ways to check intensity without overthinking it.
How to combine heart rate, RPE, and the Talk Test
Here’s the practical method I want you to use:
1) Use heart rate as your guideline
It gives you a real-time number to aim toward.
2) Use the Talk Test as your reality check
If you rate your effort at 8/10 but can sing a whole chorus, we need to recalibrate.
3) Use RPE as your body awareness skill
Over time, this is where I want you to land: you know how hard you’re working because you understand your own signals.
That’s how you stop guessing.
What to track on your heart rate monitor
If your device/app supports this, these are the metrics I like most:
Real-time heart rate
So you can see whether you’re roughly in your intended intensity.
Workout graph or timeline
This is huge for interval training. Seeing your heart rate rise and recover across sets tells a story about your conditioning and pacing.
Resting heart rate
Ideally measured first thing in the morning. As cardiovascular fitness improves, resting heart rate often trends downward.
Calorie burn (useful, but not perfect)
Many monitors estimate calorie burn. It’s an estimate—not a lab test—but it can be useful for trends, especially if you’re trying to maintain, lose, or gain weight intentionally.
Progression: The fastest way to get hurt is to do too much too soon
One of my “keep you out of trouble” rules is this:
Don’t progress more than about 10% per week
That could be duration or mileage. The point is that gradual, boring consistency wins.
In my programs, progression is built in with gradual increases, so you don’t have to guess.
Key takeaways
Exertion is the goal. Cardio becomes effective when intensity matches your purpose.
Use a heart rate monitor for guidance, but don’t rely on it alone.
Layer heart rate + RPE + the Talk Test for smarter, safer training.
Track helpful metrics: real-time HR, workout graph, resting HR, and trends in calorie burn.
Progress gradually—about 10% per week is a simple rule of thumb.
About the Author
Emma Mattison is the founder of Emma Mattison Fitness, where she helps adults 40+ build functional strength, improve cardiovascular fitness, and support long-term health with science-backed training and sustainable nutrition. She offers 1:1 online coaching and pre-made programs designed to help you train with clarity, confidence, and consistency.
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