Workout Heart Rate Calculator
Your Target Heart Rate Zones
'; outputHtml += 'Your estimated Maximum Heart Rate (MHR) is: ' + Math.round(maxHeartRate) + ' BPM'; // Calculate using Percentage of MHR method var targetHRMHR_low = maxHeartRate * lowIntensityPercent; var targetHRMHR_high = maxHeartRate * highIntensityPercent; outputHtml += 'Method 1: Percentage of Maximum Heart Rate (%MHR)
'; outputHtml += 'For your chosen intensity, your target heart rate range is: ' + Math.round(targetHRMHR_low) + ' – ' + Math.round(targetHRMHR_high) + ' BPM'; // Calculate using Karvonen Formula if resting heart rate is provided and valid if (!isNaN(restingHeartRate) && restingHeartRate >= 30 && restingHeartRate = maxHeartRate) { outputHtml += 'Your resting heart rate (' + restingHeartRate + ' BPM) cannot be greater than or equal to your maximum heart rate (' + Math.round(maxHeartRate) + ' BPM). Please check your inputs.'; } else { var heartRateReserve = maxHeartRate – restingHeartRate; var targetHRKarvonen_low = (heartRateReserve * lowIntensityPercent) + restingHeartRate; var targetHRKarvonen_high = (heartRateReserve * highIntensityPercent) + restingHeartRate; outputHtml += 'Method 2: Karvonen Formula (using Heart Rate Reserve)
'; outputHtml += 'With your resting heart rate of ' + Math.round(restingHeartRate) + ' BPM, your target heart rate range is: ' + Math.round(targetHRKarvonen_low) + ' – ' + Math.round(targetHRKarvonen_high) + ' BPM'; outputHtml += 'The Karvonen formula is generally considered more accurate as it accounts for individual fitness levels.'; } } else { outputHtml += 'Method 2: Karvonen Formula (Not Calculated)
'; outputHtml += 'To use the more precise Karvonen formula, please enter a valid resting heart rate (30-100 BPM).'; } outputHtml += 'Always consult with a healthcare professional before starting any new exercise program.'; resultDiv.innerHTML = outputHtml; } // Initial calculation on page load with default values document.addEventListener('DOMContentLoaded', function() { calculateHeartRate(); });Understanding Your Workout Heart Rate Zones
Knowing your target heart rate zones is a powerful tool for optimizing your workouts, whether your goal is weight loss, improving cardiovascular fitness, or building endurance. This calculator helps you determine these zones based on your age and, optionally, your resting heart rate.
What is Target Heart Rate?
Your target heart rate is the ideal range of heartbeats per minute (BPM) you should aim for during exercise to achieve specific fitness benefits. Exercising within these zones ensures you're working hard enough to see results, but not so hard that you risk injury or overtraining.
Maximum Heart Rate (MHR)
Your Maximum Heart Rate (MHR) is the highest number of times your heart can beat per minute during physical activity. It's a key factor in determining your target heart rate zones. While there are various formulas, this calculator uses the widely accepted Tanaka, Monahan, & Seals formula: 208 – (0.7 * Age). It's important to note that MHR is an estimate and can vary between individuals.
Heart Rate Reserve (HRR)
Heart Rate Reserve (HRR) is the difference between your Maximum Heart Rate (MHR) and your Resting Heart Rate (RHR). It represents the range of heartbeats available for exercise. A higher HRR generally indicates better cardiovascular fitness. The Karvonen formula, which uses HRR, is often considered more accurate for determining target heart rate zones because it accounts for your individual fitness level (reflected in your RHR).
Understanding Workout Intensity Zones
Different heart rate zones correspond to different physiological benefits:
- Very Light (50-60% MHR): This zone is excellent for warm-ups, cool-downs, and recovery. It's sustainable for long durations and helps improve overall health.
- Light (60-70% MHR) – Weight Management Zone: Often called the "fat-burning zone," this intensity is effective for weight loss as your body primarily uses fat for fuel. It's also good for improving basic endurance.
- Moderate (70-80% MHR) – Aerobic Zone: This zone improves cardiovascular fitness and endurance. Your breathing becomes heavier, but you can still hold a conversation. It strengthens your heart and lungs.
- Vigorous (80-90% MHR) – Anaerobic Zone: In this zone, you're working at a high intensity, and it's difficult to speak in full sentences. It builds speed, power, and tolerance for lactic acid, improving your anaerobic capacity.
- Maximum Effort (90-100% MHR): This is an all-out effort, sustainable only for very short periods. It's typically used in interval training for elite athletes and should be approached with caution.
How to Use This Calculator
- Enter Your Age: Provide your current age in years. This is essential for calculating your estimated Maximum Heart Rate.
- Enter Your Resting Heart Rate (Optional): If you know your resting heart rate (measured when you are completely at rest, typically first thing in the morning), enter it. This allows the calculator to use the more precise Karvonen formula. If you leave it blank, only the Percentage of MHR method will be displayed.
- Select Desired Workout Intensity: Choose the heart rate zone that aligns with your fitness goals from the dropdown menu.
- Click "Calculate": The calculator will instantly display your estimated Maximum Heart Rate and your target heart rate range for your chosen intensity, using both the %MHR and Karvonen formulas (if RHR is provided).
Important Considerations
While this calculator provides valuable estimates, individual heart rates can vary due to factors like fitness level, medication, stress, and environmental conditions. Always listen to your body. If you experience chest pain, dizziness, or extreme shortness of breath, stop exercising immediately and seek medical attention.
It is always recommended to consult with a doctor or a certified fitness professional before starting any new exercise program, especially if you have underlying health conditions.