RPE vs Heart Rate: Which Is Better for Tracking Training?

Should you trust a number from your watch or how hard the session felt? When it comes to RPE vs heart rate, the honest answer is that they measure related but different things, and each one catches what the other misses.

Heart rate

Heart rate tracks how hard your cardiovascular system is working, minute by minute. Over a session, it gives you an objective picture of internal load, which is why it's popular for running, cycling, and other steady endurance work.

Good at: steady aerobic training, pacing, and seeing how your body responds to the same workout over time. Where it falls short: heart rate lags behind effort at the start of hard intervals, so short bursts can look easier than they were. It's also affected by heat, hydration, caffeine, stress, and poor sleep, and it tends to drift upward during long sessions even at the same pace. For lifting and skill work, heart rate often doesn't reflect how demanding the session was. And you need a device that reads it accurately.

RPE (rating of perceived exertion)

RPE is your own rating of how hard a session felt, usually from 1 to 10. Multiply it by the session's length in minutes and you get session RPE, a simple training load number.

Good at: working for any kind of training, from intervals to lifting to sparring, and capturing things a sensor can't, like mental fatigue or a stressful day. It's also free. Research supports it: a 2004 study by Impellizzeri and colleagues found session-RPE load in soccer players lined up well with heart-rate-based measures of load.

Where it falls short: it's subjective, so mood and expectations can nudge it. It works best when you rate consistently, at the same time after each session, on the same scale.

The verdict: use both, and pay attention when they disagree

If you only use one, RPE is the more versatile choice, because it works for every type of session and costs nothing. Through race prep, when intervals, lifting, and long runs land in the same week, it's the only one that covers all of them. If you have a heart rate monitor, use both.

The most useful moments are when they don't match. If your heart rate looked normal but the session felt like a 9, something else may be going on, like poor sleep, stress, or accumulated fatigue. If heart rate ran high but the effort felt easy, heat or caffeine might explain it. Neither number is "right." Together, they give you better questions to ask. We dig into this in should you trust how you feel or your data.

Track how every session felt

Whether or not you wear a heart rate monitor, a quick effort rating after each session adds up. Sherpa is a free athlete journal that logs effort and duration after training, tracks sleep and recovery each morning, and shows how your training load changes over time. Get Sherpa on the App StoreSherpa is coming to AndroidSherpa is coming to Android.