For best accuracy, measure immediately upon waking for 3 consecutive days.
Your Calculated Lowest (Resting) HR: — bpm
Fitness Category: —
Estimated Max Heart Rate: — bpm
Health Note: —
How to Calculate Your Lowest Heart Rate
Your lowest heart rate, medically referred to as your Resting Heart Rate (RHR), is one of the most efficient indicators of cardiovascular health and fitness. Unlike your active heart rate, which fluctuates wildly based on activity, your lowest heart rate provides a baseline metric of your heart's efficiency.
What is Lowest Heart Rate?
The "lowest" heart rate generally refers to the minimum number of times your heart beats per minute (BPM) while you are completely at rest. For most people, this occurs immediately upon waking up in the morning, before getting out of bed, drinking coffee, or checking stressful emails. A lower RHR typically indicates that your heart muscle is stronger and pumps blood more efficiently, requiring fewer beats to maintain circulation.
How to Measure Accurately
While you can use heart rate monitors or smartwatches, the manual method is often reliable for spot-checking. To get a true "lowest" calculation:
Timing: Measure immediately after waking up naturally (without a jarring alarm if possible).
Position: Stay lying down in bed. Do not sit up or stand.
Technique: Place your index and middle fingers on your wrist (radial artery) or neck (carotid artery). Count the beats for 60 seconds, or count for 15 seconds and multiply by 4.
Averaging: Because factors like sleep quality and hydration affect daily readings, it is best practice to take measurements over 3 consecutive days and calculate the average. This is what the calculator above does for you.
Interpreting the Numbers
The average adult resting heart rate ranges from 60 to 100 bpm. However, fit individuals often see lower numbers.
Athlete: 40–60 bpm. Highly conditioned endurance athletes may have rates as low as 40.
Excellent: 60–69 bpm.
Average: 70–79 bpm.
Below Average: 80+ bpm.
If your lowest heart rate is consistently above 100 bpm (tachycardia) or below 60 bpm without being an athlete (bradycardia) accompanied by dizziness, you should consult a healthcare professional.
Factors That Influence Your Lowest HR
If your calculation seems higher than expected, consider these factors:
Stress & Anxiety: High cortisol levels can elevate RHR.
Medication: Beta-blockers lower HR, while some thyroid meds increase it.
Temperature: Hot weather can slightly increase your pulse.
Dehydration: Thickens blood, making the heart work harder.
function calculateLowestHR() {
// Get input values
var age = parseInt(document.getElementById('ageInput').value);
var gender = document.getElementById('genderInput').value;
var bpm1 = parseFloat(document.getElementById('bpm1').value);
var bpm2 = parseFloat(document.getElementById('bpm2').value);
var bpm3 = parseFloat(document.getElementById('bpm3').value);
// Validation
if (isNaN(age) || age 120) {
alert("Please enter a valid age.");
return;
}
// Calculate Average RHR
var totalBPM = 0;
var count = 0;
if (!isNaN(bpm1)) { totalBPM += bpm1; count++; }
if (!isNaN(bpm2)) { totalBPM += bpm2; count++; }
if (!isNaN(bpm3)) { totalBPM += bpm3; count++; }
if (count === 0) {
alert("Please enter at least one heart rate measurement.");
return;
}
var avgRHR = Math.round(totalBPM / count);
// Calculate Max Heart Rate Estimate
var maxHR = 220 – age;
// Determine Fitness Category based on RHR, Gender and Age
// Simplified generic norms adapted from YMCA and AHA data
var category = "";
var note = "";
// Standard norms
if (avgRHR = 60 && avgRHR = 70 && avgRHR = 80 && avgRHR 75 && avgRHR < 85) {
note += " Note: Women naturally have slightly higher heart rates than men.";
}
// Display Results
document.getElementById('displayRHR').innerHTML = avgRHR;
document.getElementById('displayCategory').innerHTML = category;
document.getElementById('displayMaxHR').innerHTML = maxHR;
document.getElementById('displayNote').innerHTML = note;
document.getElementById('resultBox').style.display = "block";
}