Active Target Heart Rate Calculator
Using the Karvonen Formula for precision training.
Optimizing Cardio with Active Target Heart Rate
Whether you are training for a marathon, trying to lose weight, or simply maintaining cardiovascular health, understanding your Active Target Heart Rate is crucial. Training blindly without monitoring heart rate can lead to under-training (seeing no results) or over-training (risking injury and burnout).
This calculator utilizes the Karvonen Formula, which is widely considered more accurate for athletes and fitness enthusiasts than the standard "220 minus age" formula because it accounts for your Resting Heart Rate (RHR). Your RHR is a key indicator of your current fitness level; the fitter you are, the lower your RHR, and the Karvonen formula adjusts your training zones accordingly.
How the Calculation Works
To find your ideal training intensity, we calculate your Heart Rate Reserve (HRR). The logic follows three steps:
- Estimate Maximum Heart Rate (MHR): Standard calculation is 220 – Age.
- Calculate Heart Rate Reserve (HRR): MHR – Resting Heart Rate.
- Determine Target Zone: (HRR × Intensity %) + Resting Heart Rate.
For example, a 30-year-old with a resting heart rate of 60 BPM who wants to train at 70% intensity would calculate:
- Max HR: 190 BPM
- HR Reserve: 130 (190 – 60)
- Target: (130 × 0.70) + 60 = 151 BPM
Heart Rate Training Zones Explained
Selecting the right "Desired Intensity" in the calculator depends on your specific fitness goals:
Zone 1: Warm Up / Recovery (50-60%)
Ideal for beginning a workout or recovering the day after a hard session. This zone improves overall health and helps recovery.
Zone 2: Fat Burning (60-70%)
This is the "conversation pace." Your body becomes more efficient at oxidizing fat for fuel. Endurance athletes spend 80% of their time here.
Zone 3: Aerobic Capacity (70-80%)
Improving blood circulation and lung capacity. You will breathe harder and start to feel the effort in your muscles.
Zone 4: Anaerobic Threshold (80-90%)
High-intensity training. You can only sustain this for shorter bursts. This improves speed and lactate tolerance.
Zone 5: Maximum Effort (90-100%)
All-out effort for very short durations (sprints). Consult a doctor before training in this zone.
Why Resting Heart Rate Matters
Your input for "Resting Heart Rate" significantly changes the outcome. Two people of the same age will have the same estimated maximum heart rate, but if one has a RHR of 50 (very fit) and the other has 80 (sedentary), their training targets will differ. The fitter individual has a larger "Heart Rate Reserve," meaning they can elevate their heart rate higher before reaching fatigue relative to their baseline.
To get the most accurate result from this calculator, measure your pulse for 60 seconds immediately after waking up in the morning, before getting out of bed or drinking coffee.