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Calculate Metabolic Index of Vital Function (MIVF)—a teaching composite from Boer-style lean body mass, age, and activity level. Shows score, risk category, BMI, and clinical context. Not IVF fertility treatment. Pair with our lean body weight calculator and BMI calculator. Educational—not DEXA, FRAIL, or blood work.
Last updated: June 5, 2026
MIVF estimates functional reserve from height, weight, sex, age, and activity—it does not measure muscle quality, visceral fat, or metabolic labs directly.
50.6
BMI 22.9 kg/m²
High
Very Low Risk
Default — male 35 y, 70 kg, 175 cm, moderate
50.6
High — BMI 22.9
Active male 25 y, 75 kg, 180 cm
59.4
High
Female 45 y, 62 kg, 165 cm, moderate
40.9
High
Sedentary female 68 y, 72 kg, 158 cm
34.1
Above Average
Final MIVF = Boer-style base × age factor × activity factor.
BMI = 70 ÷ (1.75)² = 22.9 kg/m²
Male base = (0.407×70) + (0.267×175) − 19.2 = 56
Age factor (age 35): ×0.95
Activity (moderate): ×0.95
MIVF = 56 × 0.95 × 0.95 = 50.6
Category: High — Very Low Risk
| Sex | Equation | Origin |
|---|---|---|
| Male | Base MIVF = (0.407 × weight kg) + (0.267 × height cm) − 19.2 | Boer et al. lean body mass equation (modified) |
| Female | Base MIVF = (0.252 × weight kg) + (0.473 × height cm) − 48.3 | Boer et al. lean body mass equation (modified) |
| Age | Factor |
|---|---|
| <30 years | ×1.00 |
| 30–49 years | ×0.95 |
| 50–69 years | ×0.90 |
| ≥70 years | ×0.85 |
| Level | Factor |
|---|---|
| Sedentary | ×0.85 |
| Light | ×0.90 |
| Moderate | ×0.95 |
| Active | ×1.00 |
| Very active | ×1.05 |
| Score | Category | Risk | Action |
|---|---|---|---|
| <15 | Very Low | High risk | Urgent clinical evaluation for malnutrition or chronic illness |
| 15–19.9 | Low | Moderate risk | Medical follow-up; nutrition and resistance training |
| 20–24.9 | Below Average | Low–moderate risk | Improve protein intake and structured exercise |
| 25–29.9 | Average | Low risk | Maintain current habits; annual preventive care |
| 30–34.9 | Above Average | Very low risk | Strong metabolic reserve; continue fitness routine |
| ≥35 | High | Very low risk | Excellent lean-mass proxy; routine monitoring only |
| Lever | Effect on score |
|---|---|
| Resistance training | Increases lean mass → raises base Boer component |
| Protein intake | Supports muscle protein synthesis; 1.2–1.6 g/kg/day often cited for older adults |
| Activity level upgrade | Sedentary → moderate raises multiplier 0.85 → 0.95 (~12% relative) |
| Weight management | Excess fat lowers functional ratio; modest fat loss may improve category if muscle preserved |
| Tool | Measures | Best for |
|---|---|---|
| MIVF (this page) | Boer-style lean mass + age + activity composite score | Single-number metabolic reserve teaching screen |
| Lean body weight calculator | LBM kg via Boer, James, or Hume | Formula comparison and implied body fat % |
| BMI calculator | Weight ÷ height² | Population weight category—not muscle mass |
| BMR / TDEE calculator | Resting or total daily energy expenditure | Calorie targets—not functional capacity index |
Education only. MIVF is not a validated clinical score, not DEXA, and not a substitute for metabolic labs. Seek medical care for unintentional weight loss, weakness, or abnormal test results.
For fitness education, body composition teaching, and health literacy
Suggested hashtags: #MetabolicHealth #BodyComposition #Fitness #MedEd