Heart Rate Zones:
"; zoneResults += "Estimated Max Heart Rate: " + maxHeartRate.toFixed(0) + " bpm"; zoneResults += "Heart Rate Reserve: " + heartRateReserve.toFixed(0) + " bpm"; zoneResults += "- ";
for (var zoneName in zones) {
var lowerPercentage = zones[zoneName].lower;
var upperPercentage = zones[zoneName].upper;
var lowerBound = Math.round((heartRateReserve * lowerPercentage) + restingHeartRate);
var upperBound = Math.round((heartRateReserve * upperPercentage) + restingHeartRate);
// Ensure bounds do not exceed Max Heart Rate or go below Resting Heart Rate
lowerBound = Math.max(lowerBound, restingHeartRate);
upperBound = Math.min(upperBound, maxHeartRate);
zoneResults += "
- " + zoneName + ": " + lowerBound + " – " + upperBound + " bpm "; } zoneResults += "
Understanding Heart Rate Zones
Heart rate zones are specific ranges of heartbeats per minute that correspond to different exercise intensities. Training within these zones allows you to optimize your workouts for various goals, such as improving cardiovascular health, building endurance, or burning fat. Most modern fitness watches and heart rate monitors utilize these zones to guide your training intensity.
How Heart Rate Zones Are Calculated
The most common method for calculating heart rate zones involves determining your Maximum Heart Rate (MHR) and your Resting Heart Rate (RHR).
- Maximum Heart Rate (MHR): This is the highest number of times your heart can beat in one minute during maximal exertion. While some individuals can have their MHR measured directly through a stress test, a widely used and simple formula to estimate MHR is: 220 – Age. For example, a 30-year-old individual would have an estimated MHR of 220 – 30 = 190 bpm. Some individuals may know their actual MHR from previous testing, and this can be used for a more personalized calculation.
- Resting Heart Rate (RHR): This is the number of times your heart beats per minute when you are completely at rest, typically measured first thing in the morning before getting out of bed. A lower RHR generally indicates better cardiovascular fitness. You can measure your RHR by placing two fingers on your wrist or neck and counting beats for 60 seconds, or for 15 seconds and multiplying by four.
- Heart Rate Reserve (HRR): This is the difference between your MHR and your RHR. It represents the range of heartbeats available for your workout. HRR = MHR – RHR.
The Karvonen Formula
The Karvonen formula is a popular method that uses your HRR to calculate your target heart rate zones. It's considered more accurate than formulas that only use MHR because it accounts for your individual fitness level (as reflected by your RHR). The formula is:
Target Heart Rate = [(Max Heart Rate – Resting Heart Rate) × % Intensity] + Resting Heart Rate
Here, "% Intensity" refers to the desired percentage of your Heart Rate Reserve that you aim to work within.
Common Heart Rate Zones and Their Benefits
The calculator above uses the Karvonen formula to estimate your heart rate zones, typically categorized as follows:
- Very Light (50-60% of MHR): This zone is great for active recovery, warm-ups, and cool-downs. It helps improve basic endurance and can aid in fat burning.
- Light (60-70% of MHR): This zone is excellent for building aerobic fitness and improving endurance. It's often referred to as the "fat-burning zone" because a higher percentage of calories burned come from fat.
- Moderate (70-80% of MHR): This zone is where you improve your aerobic capacity and efficiency. It's a common zone for many athletes during longer training sessions.
- Hard (80-90% of MHR): Training in this zone significantly improves your anaerobic threshold and speed. It's ideal for improving performance and building strength.
- Maximum (90-100% of MHR): This zone is for very short, high-intensity intervals. It pushes your limits and is crucial for improving your top-end speed and power. It should be used sparingly.
Example Calculation
Let's consider a 45-year-old individual with a resting heart rate of 55 bpm.
- Estimated Max Heart Rate = 220 – 45 = 175 bpm.
- Heart Rate Reserve = 175 bpm (MHR) – 55 bpm (RHR) = 120 bpm.
Now, let's calculate the Moderate Intensity Zone (70-80%):
- Lower end (70%): [(120 bpm × 0.70) + 55 bpm] = [84 + 55] = 139 bpm.
- Upper end (80%): [(120 bpm × 0.80) + 55 bpm] = [96 + 55] = 151 bpm.
So, for this individual, the Moderate heart rate zone is approximately 139-151 bpm.
Using a heart rate zone calculator like the one above can help you personalize your training, ensure you're working at the right intensity for your fitness goals, and avoid overtraining or undertraining.