Tracking Exercise Intensity
Heart Rate Zones & Rate of Perceived Exertion Scale
You can use heart rate zones or the rate of perceived exertion scale to assess and track how hard your body is working during exercise. Read more about each below.
Healthy Heart Rate Zones
Heart rates are measured in beats per minute (bpm).
Rate of Perceived Exertion Scale
The Rate of Perceived Exertion (RPE) scale can be used as an alternative to target heart rate zones. This is a 1-to-10 scale that gauges effort based on breathing rate, talking ability, and muscle fatigue.
Your rate of perceived exertion refers to how hard you think you’re pushing yourself during exercise. It’s subjective, which means that you decide how hard you feel you’re working during physical activity.
When doing cardio for an extended period of time, aim for 5 to 8 on the RPE scale.
The RPE scale can also be used when strength training. The best RPE for building maximum strength is 7 to 9 for heavy working sets, with the majority of overall training volume landing in the 5 to 8 range.
Reference the RPE scale below.
RPE Scale
1 | Very Light Activity It doesn't even feel like you're exercising. |
2-3 | Light Activity You could keep going for hours. It's easy to breathe and have a conversation. |
4-6 | Moderate Activity You're breathing heavy, but you can have a conversation. |
7-8 | Somewhat Difficult Activity You're short of breath. You can speak, but only one sentence at a time. |
9 | Very Difficult Activity You can barely breathe, and can only say a few words at a time. |
10 | Maximum Effort Activity You're completely out of breath, and cannot talk. |
Questions about heart rate and medications, consult your doctor.
Download the pdf version below:
Sources:
Mayo Clinic. (2020). What's a normal resting heart rate.
American Heart Association (AHA). (2021). Target Heart Rates Chart.
Stronger By Science (2025). What’s the best RPE for gaining strength?