Heart Rate Zones Calculator (Reddit Edition)
Optimize your Zone 2 training and peak performance using the Karvonen Formula.
Your Personalized Training Zones
Max Heart Rate: BPM
Heart Rate Reserve (HRR): BPM
| Zone | Intensity | Range (BPM) |
|---|---|---|
| Zone 1 Recovery |
50% – 60% | |
| Zone 2 Aerobic Base |
60% – 70% | |
| Zone 3 Tempo |
70% – 80% | |
| Zone 4 Threshold |
80% – 90% | |
| Zone 5 Anaerobic |
90% – 100% |
Understanding Heart Rate Zones for Optimal Fitness
If you have spent any time on fitness subreddits like r/running, r/cycling, or r/fitness, you have likely heard about the "Zone 2 craze." Training in specific heart rate zones allows you to target different physiological adaptations, from building a massive aerobic engine to increasing your top-end sprinting power.
What is the Karvonen Formula?
While the standard "220 minus age" formula is a quick shortcut, it is often inaccurate because it ignores your Resting Heart Rate (RHR). The Karvonen Formula, used in this calculator, factors in your heart rate reserve (the difference between your max HR and resting HR). This provides a much more personalized set of training ranges that reflect your actual fitness level.
Breakdown of the 5 Training Zones
- Zone 1 (50-60%): Very light activity. Used for active recovery and warming up. You should be able to hold a full conversation easily.
- Zone 2 (60-70%): The "Sweet Spot." This is where you build endurance and improve fat oxidation. You can still speak in full sentences, but you're working. Reddit highly recommends this for long-term health.
- Zone 3 (70-80%): Moderate intensity. Often called the "Gray Zone," it's effective for aerobic capacity but requires more recovery than Zone 2.
- Zone 4 (80-90%): High intensity. This improves your lactate threshold. You can only speak in short, broken sentences.
- Zone 5 (90-100%): Maximum effort. Sprinting and HIIT. This is for improving peak power and VO2 max.
Example Calculation
If you are 30 years old with a resting heart rate of 60 BPM:
- Max HR: 220 – 30 = 190 BPM
- HR Reserve: 190 – 60 = 130 BPM
- Zone 2 Lower Limit: (130 * 0.60) + 60 = 138 BPM
- Zone 2 Upper Limit: (130 * 0.70) + 60 = 151 BPM
In this case, your Zone 2 "Reddit" training range would be 138 to 151 BPM.