Heart Rate Hiit Calculator

HIIT Heart Rate Zone Calculator

Your HIIT Targets

Max Heart Rate

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BPM

Work (High)

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BPM

Rest (Recovery)

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BPM

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Understanding Heart Rate for HIIT Training

High-Intensity Interval Training (HIIT) relies on pushing your cardiovascular system to its limit for short bursts, followed by brief recovery periods. To get the most out of your workout without overtraining or under-performing, calculating your target heart rate zones is essential.

The Karvonen Formula

This calculator uses the Karvonen Formula, which is widely considered more accurate than simple age-based formulas because it incorporates your Resting Heart Rate (RHR). By calculating your Heart Rate Reserve (HRR), we can pinpoint exactly how hard your heart should be working during both the work and rest phases of your HIIT circuit.

HIIT Intensity Targets

A standard HIIT protocol usually targets specific intensity percentages:

• Work Phase (80% – 95%): This is the "sprint" phase. You should be working at a level where conversation is nearly impossible.
• Recovery Phase (50% – 65%): This is the "active rest" phase. Your heart rate should drop significantly to prepare for the next interval, but you should keep moving (walking or light jogging).

Practical Examples

Let's look at how these numbers change based on fitness level and age:

• 25-Year-Old Athlete: With a resting heart rate of 50 BPM, their 90% HIIT work target is 181 BPM.
• 45-Year-Old Beginner: With a resting heart rate of 75 BPM, their 85% HIIT work target is 160 BPM.
• Recovery Note: If your heart rate doesn't drop by at least 15-20 BPM during your rest interval, you may need to extend your recovery time or lower your intensity.

Safety First

Before starting any HIIT program, ensure you have medical clearance, especially if you have high blood pressure or heart conditions. HIIT is taxing on the central nervous system and the heart. Always include a 5-10 minute warm-up and cool-down to prevent injury and manage heart rate transitions safely.

function calculateHIITZones() { var age = parseFloat(document.getElementById('hiit_age').value); var rhr = parseFloat(document.getElementById('hiit_rhr').value); var workPct = parseFloat(document.getElementById('hiit_work_pct').value); var restPct = parseFloat(document.getElementById('hiit_rest_pct').value); if (isNaN(age) || isNaN(rhr) || isNaN(work_pct) || isNaN(rest_pct) || age <= 0 || rhr <= 0) { if (isNaN(age) || age <= 0) { alert("Please enter a valid age."); return; } if (isNaN(rhr) || rhr <= 0) { alert("Please enter a valid resting heart rate."); return; } } // Calculations var maxHR = 220 – age; var hrr = maxHR – rhr; var targetWork = Math.round((hrr * (workPct / 100)) + rhr); var targetRest = Math.round((hrr * (restPct / 100)) + rhr); // Update UI document.getElementById('res_mhr').innerHTML = maxHR; document.getElementById('res_work').innerHTML = targetWork; document.getElementById('res_rest').innerHTML = targetRest; var summaryText = "Training Insight: For your HIIT session, aim to reach " + targetWork + " BPM during your high-intensity intervals. During your recovery phase, your goal is to var your heart rate settle back down toward " + targetRest + " BPM. This spread of " + (targetWork – targetRest) + " BPM is key to the metabolic benefits of interval training."; document.getElementById('zone_summary').innerHTML = summaryText; document.getElementById('hiit_results').style.display = 'block'; // Smooth scroll to results document.getElementById('hiit_results').scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }