Understanding Your Health Numbers: BMI, BMR, TDEE

Your health can be partially described by a set of numbers — metrics that, when tracked over time, give you meaningful signals about your risk of preventable disease. Most of these numbers are simple enough to calculate yourself with basic measurements, yet many people have never checked several of them. This guide covers the key health metrics worth tracking, what they mean, and their limitations.

Body Mass Index: The Standard Screening Tool

BMI is the most universally used screening metric for weight relative to height. It is calculated as weight in kilograms divided by height in metres squared.

Bmi Formula Bmi

For adults, the WHO defines: - Below 18.5: Underweight - 18.5–24.9: Normal weight - 25.0–29.9: Overweight - 30.0 and above: Obese

BMI has well-documented limitations: it cannot distinguish fat from muscle, and it does not account for fat distribution (abdominal fat is more dangerous than peripheral fat). Athletes, the elderly, and people with high bone density may receive misleading classifications. Use BMI as a starting point, not a definitive verdict.

Basal Metabolic Rate: Your Energy Baseline

Your Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest just to sustain basic functions — breathing, circulation, and temperature regulation. It forms the foundation of any calorie budget.

The most commonly used formula is the Mifflin-St Jeor equation: - For men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5 - For women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161

BMR is multiplied by an activity factor to estimate Total Daily Energy Expenditure (TDEE): - Sedentary (little or no exercise): BMR × 1.2 - Lightly active (1–3 days/week): BMR × 1.375 - Moderately active (3–5 days/week): BMR × 1.55 - Very active (6–7 days/week): BMR × 1.725

Calorie

Waist-to-Height Ratio: A Better Abdominal Risk Indicator

Waist circumference is a stronger predictor of cardiometabolic risk than BMI, because abdominal fat (surrounding the liver and other organs) is more metabolically active and dangerous than subcutaneous fat. The waist-to-height ratio (WHtR) is even more useful because it adjusts waist size for body size.

Formula: Waist circumference ÷ Height (in the same unit)

A WHtR below 0.5 is generally considered healthy for most adults. The rule-of-thumb "keep your waist to less than half your height" is simple, memorable, and applicable regardless of gender or ethnicity.

Blood Pressure: The Silent Vital Sign

Blood pressure is expressed as two numbers: systolic (pressure when the heart beats) over diastolic (pressure between beats), measured in millimetres of mercury (mmHg).

Category	Systolic	Diastolic
Normal	Below 120	Below 80
Elevated	120–129	Below 80
Hypertension Stage 1	130–139	80–89
Hypertension Stage 2	140+	90+
Hypertensive Crisis	180+	120+

Blood pressure varies throughout the day and with stress, caffeine, and exercise. A single reading is less meaningful than an average over multiple readings taken at different times. Home monitors are inexpensive and enable consistent tracking.

Resting Heart Rate: A Window Into Cardiovascular Fitness

Resting heart rate (RHR) is your pulse measured after at least five minutes of inactivity, ideally first thing in the morning before getting out of bed.

• Below 60 bpm: Often seen in highly fit individuals; can also indicate bradycardia — discuss with a doctor if accompanied by symptoms
• 60–100 bpm: Normal adult range
• Above 100 bpm: Tachycardia; warrants investigation if persistent

A gradual decrease in resting heart rate over weeks of consistent aerobic exercise is one of the clearest physiological signals of improving cardiovascular fitness. Conversely, a sudden unexplained increase of 5–10 bpm above your normal baseline can indicate overtraining, illness, or stress.

Blood Glucose: A Key Metabolic Marker

For people at risk of type 2 diabetes (family history, obesity, sedentary lifestyle), fasting blood glucose and HbA1c are critical numbers.

• Fasting blood glucose: Normal is below 100 mg/dL; 100–125 is prediabetes; 126+ on two tests is diagnostic for diabetes
• HbA1c: Reflects average blood glucose over approximately three months. Below 5.7% is normal; 5.7%–6.4% is prediabetic; 6.5%+ is diabetic

These figures require a blood test, but home fasting glucose monitors are widely available and inexpensive for routine monitoring.

Building a Personal Health Dashboard

Rather than tracking all metrics simultaneously, start with the two or three most relevant to your current health concerns or risk factors. Someone with a family history of heart disease should prioritise blood pressure and waist-to-height ratio. Someone trying to manage weight should focus on BMI trajectory, calorie balance, and BMR. Someone improving fitness should watch resting heart rate.

Track numbers over time rather than fixating on a single reading. A single BMI measurement is a snapshot; a year of monthly measurements is a trend that reveals the direction of travel.

Bmi Calorie