MinuteMetric

Understanding Your Health Numbers

Health metrics are easy to collect and easy to over-interpret. A BMI figure, a body fat estimate, a daily water target — each one compresses something complicated into a single number, and each one is built on population averages that may or may not describe you well. Used properly they're genuinely useful; used as verdicts they mislead.

The tools in this category cover body composition, daily energy needs, hydration, sleep timing and heart rate. They rely on established formulas — Mifflin-St Jeor for metabolic rate, the US Navy method for body fat, standard heart-rate zone models — and each page explains the formula it uses so you can see exactly where the number comes from.

Getting Useful Results

• Measure consistently. Same time of day, same conditions. Day-to-day variation from food, salt and hydration is larger than most people expect, and it can easily swamp real change.
• Watch the trend, not the reading. A single measurement tells you very little. Four weeks of measurements tells you a direction, which is the part that matters.
• Use more than one metric. BMI, waist measurement and a fitness marker together give a far better picture than any of them alone — they fail in different ways.
• Know what a formula can't see. None of these estimates knows your medical history, medication, or how you actually feel. They're a starting point for a conversation with a doctor, not a replacement for one.