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BMI for athletes and muscular people
BMI uses only height and weight, so it cannot tell muscle from fat.
Muscle is denser than fat. Someone who is 6 ft tall and weighs 190 lb has a BMI of 25.8, which falls in the overweight category even if they are lean and strong. BMI cannot see body composition, so it can misread people who lift, sprint, or play contact sports.
Better measures for athletes
- Waist circumference. Commonly cited risk thresholds are over 40 inches for men and over 35 inches for women.
- Waist-to-height ratio. Divide waist by height. Staying under 0.5 is a widely used guideline.
- Body fat percentage. Options include DEXA scans, skinfold calipers, and bioimpedance scales. Accuracy varies by method, so compare like with like over time.
- Health markers. Blood pressure, cholesterol, fasting glucose, and resting heart rate show health risk more directly than weight does.
When BMI still helps
BMI is still a reasonable quick check for many recreational athletes, and it can flag the other direction too. A BMI below 18.5 in an athlete is worth discussing with a doctor or sports dietitian, since eating too little for your training can affect hormones, bones, and recovery.
Common questions
Why does BMI call muscular people overweight?
BMI is weight divided by height squared. It does not know how much of that weight is muscle, so a lean, muscular person can score the same as someone with more body fat.
Is waist-to-height ratio better than BMI?
It often tracks fat around the midsection, which is linked to health risk, more closely than BMI does. It still does not replace a medical assessment.
Should athletes ignore BMI?
Not necessarily. Treat it as one rough screening number and look at waist size, body fat, and health markers with a doctor if your result does not match how you look and perform.