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Today, runners can track everything from stride length to sleep cycles, recovery scores to training readiness. The market is flooded with tools that promise insight, optimization, and marginal gains. But in the midst of all this high-tech data, one simple, time-tested metric remains nearly unbeatable: heart rate.
Heart-rate training is accessible, personal, and incredibly powerful when used correctly. Whether you’re chasing a marathon PR or trying to stay healthy for the long haul, heart-rate training remains one of the smartest tools in a runner’s kit. Here’s why, according to the experts.
Heart-Rate Training Creates Your Running Foundation
Low-intensity, aerobic runs are the bread and butter for all runners, but especially for those in the beginner to intermediate range. They help build a strong aerobic foundation and physical resilience, or “durability.”
“At the basement level, these are your aerobic, sub-maximal runs,” says Paul Laursen, performance physiology coach and co-author of The Science and Application of High-Intensity Interval Training. Those sub-maximal runs he’s talking about? Just a fancy name for your easy runs.
You may have heard of this kind of training referred to as “Zone 2 training.” Zone 2 training is the highest level of exertion you can achieve without an accumulation of lactate, which means you’re still in an aerobic state and your muscles have enough oxygen to efficiently burn fat as fuel.
In the ‘70s, heart-rate guru Phil Maffetone proposed the 180 Formula to estimate an athlete’s Zone 2 heart rate, and while testing can be a more robust indicator of heart-rate zones, his basic formula is a fine starting point for beginners.
Use 180 minus your age to find your number. (e.g., 180 – 45 = 135) Now, apply a modifier to this number depending on your health and training status to find your Zone 2 training number:
- + 5 bpm if training for 2 years or more/making good progress
- – 5 bpm if injured, sick, or not improving on your training
- -10 bpm If recovering from a major illness or overtraining
- No change if training consistently for 2 years/no issues
“Your pace at your Zone 2 heart rate should hold through the course of your run,” Laursen says. If it falls steadily, that shows a limited aerobic endurance and limited ability to burn fat as a fuel.
He adds that if your heart rate is always high on your runs, you’re going to have to slow down before you can speed up. This can be a challenge for runners of all levels. “The hardest thing to do is slow down and walk for a bit. But there’s a reward,” Laursen says.
It Can Be More Accurate Than RPE
While Rate of Perceived Effort (RPE) is often used to guide training, especially in group settings or when tech isn’t available, it’s inherently subjective. One runner’s “easy” might be another’s “moderate,” depending on mood, sleep, stress levels, and experience.
Heart rate offers a somewhat objective number. It tells you how your body is actually responding to effort in real time, not just how hard you think you’re working. It’s also incredibly effective for newer runners who might think their easy runs are easy enough when they really are not. Being able to check your heart rate and ensure it’s not too high during Zone 2 runs makes it way easier to build aerobic endurance without going too fast and overtraining.
It’s worth noting that the best approach is a combo of RPE and heart rate, because your aerobic power house could be better trained than your musculoskeletal system. One recent study on heart-rate training in recreational athletes noted that sometimes runners’ legs would feel a greater training load before their heart rate reflected it.
It’s the Most Accessible Metric for all Runners
We have so many tools at our fingertips these days. Power meters, VO2 max testing, lactate testing, to name a few. These insights, once for elites only, are now available to the average runner. But heart rate still wins the accessibility contest, with its relatively low price tag.
“Heart rate is still the easiest, most widely available metric,” says Jim Finlayson, a Canadian Masters world record holder and coach based in Victoria, BC.
RELATED: The Truth About Running in the Grey Zone (Heart Rate Zone 3)
For under $200, you can access heart-rate metrics and do basic time/distance tracking with a smartwatch. Many models of heart-rate monitors offer heart rate variability, sleep tracking, Zone graphs, structured workouts, and more. While wrist-based heart rate monitors, like those on your running watch, have gotten more accurate, Finlayson says that a chest strap will give you the most accurate data.
Heart Rate Training Allows for Optimal Training Load
A third area where heart rate does a particularly good job is contributing to a key metric called “training load.” Training load refers to the total amount of physical stress your body experiences from training over time. It’s a combination of:
- Volume: How much you train: mileage, time, frequency
- Intensity: How hard each session is, often measured by effort or heart rate
- Duration: How long those efforts last.
Your heart-rate data, especially when tracked cumulatively across workouts, can help identify if you’re pushing too hard (risking overtraining) or not hard enough (missing key adaptations). For example, if your heart rate is unusually high during a run that should feel easy, your body may be under more stress than you realize. If it’s unusually low during hard efforts, you might be heading toward burnout.
“You can get a sense of where you are with respect to your training load,” Finlayson adds. “Are you overreaching, or can you stand to increase the load a little bit? “
It Helps You Nail Your Recovery
Speaking of recovery, as many of us know all too well, increased fitness brings increased fatigue. If you don’t balance your intense efforts with recovery, this fatigue can lead to overtraining, illness, and injury.
You can use your heart rate to gauge whether or not you need more recovery. You can keep an eye on it while you’re running and throughout the day, but the most accurate way to tell is by tracking your resting heart rate first thing in the morning. If your heart rate is either lower or higher than normal, it could mean that you need more rest.
“In an overtrained state, heart rate response can be dampened (lower) given the effort,” Finlayson says. “This is not necessarily a good thing.” In this situation, he says the athlete likely needs more recovery, in the form of sleep, better nutrition, or a decrease in training load.
If the heart rate is abnormally high, he suggests looking at things like life stress, diet, or caffeine, all of which can cause heart rate to go up.
General Health and Longevity
We’ve already seen how heart rate can guide Zone 2 training, but its benefits go beyond performance. It’s also become a must-have tool for supporting long-term health and longevity. Laursen explains that consistent Zone 2 work strengthens your aerobic system and keeps your mitochondria (the energy-producing powerhouses of your cells) functioning efficiently, and isn’t just a fitness trend.
“Zone 2 training is synonymous with being able to burn more fat, and also correlates with VO2 max, which is a key marker for living longer,” he says. “Merging these two is the ultimate recipe for health and longevity.”
Finally, because heart rate training helps you monitor training load and keep your effort in check, it lowers your risk of overtraining and burnout, making it a smart tool for both short-term gains and lifelong consistency.
Heart Rate Training Tools for Beginners
Interested in exploring heart rate as a metric for training, recovery, and living better? Here’s a checklist, from essential to more advanced add-ons, that will help you get started.
- Heart-rate enabled watch: Garmin Forerunner 55, Coros Pace 3, Polar Pacer,
- Chest strap for more accurate tracking: Wahoo TRACKR, Garmin HRM 200, Polar H9
- Software to help interpret the data: This might come free of charge with your watch (for example, the app. Garmin Connect keeps track of your heart rate automatically). You can also subscribe to Strava Premium or programs like Athletica.ai or TrainingPeaks for more feedback on your heart rate and general training.