代謝年齢とは？
代謝年齢はあなたのBMRを同年齢の人の平均BMRと比較します。
代謝年齢は生物学的年齢とは異なります。
代謝年齢がBMIより重要な3つの理由
1
BMIは筋肉量を無視します。
2
代謝年齢は臓器の効率を明らかにします。
3
代謝年齢が高い = 警告サイン。
無料オンライン計算機 — メール不要
無料代謝年齢計算機
60秒であなたの本当の体年齢を発見
下にデータを入力してください。代謝年齢、BMR、BMIを即座に取得 — 無料、登録不要。
✓ メール不要 ✓ Mifflin-St Jeor式 ✓ 男女別結果 ✓ 100,000人以上が利用
あなたの代謝年齢を計算
単位：
活動ベースのカロリー需要とライブMifflin–St Jeor BMR。
プロファイル
男女別の結果。
体サイズ
あなたのBMR
0
カロリー/日 式
Mifflin–St Jeor
±5% accuracy ヒント
活動係数を選択
TDEEを推定ℹ この計算機の仕組み
このツールはMifflin–St Jeor方程式を使用して基礎代謝率（BMR）を推定します。
📝
データを入力
年齢、性別、身長、体重
⚡
即座に計算
Mifflin–St Jeor式がリアルタイムで実行
📊
結果を取得
BMR + 活動ベースのTDEE
💡 クイックヒント
- • 正確な身長/体重を使用してください。
- • 週の習慣に最も合う活動を選択してください。
- • 持続可能な目標のために適度なカロリー変更を目指してください。
代謝年齢の計算方法
代謝年齢を計算するには、以下の3ステップに従ってください：
1
BMRを計算
BMRは完全安静時に体が燃焼するカロリー数です。
| Formula | Best For | Accuracy |
|---|---|---|
| Mifflin-St Jeor | Most people — recommended | Highest (±5%) |
| Harris-Benedict (Revised) | General adults | Moderate (±8%) |
| Katch-McArdle | People who know body fat % | Highest for lean individuals |
Mifflin-St Jeor Formula:
男性: (10 × kg) + (6.25 × cm) − (5 × age) + 5
女性: (10 × kg) + (6.25 × cm) − (5 × age) − 161
2
BMRを年齢グループ平均と比較
| Age Group | Avg Male BMR | Avg Female BMR | Notes |
|---|---|---|---|
| 20–29 | 1,900–2,000 | 1,550–1,650 | Peak metabolic rate |
| 30–39 | 1,800–1,900 | 1,480–1,580 | Drops ~2%/decade |
| 40–49 | 1,700–1,800 | 1,400–1,500 | Muscle loss accelerates |
| 50–59 | 1,600–1,700 | 1,320–1,420 | Hormonal shifts begin |
| 60–69 | 1,500–1,600 | 1,250–1,350 | Sedentary risk rises |
| 70+ | 1,400–1,500 | 1,180–1,280 | Frailty prevention critical |
3
代謝年齢スコアを決定
計算したBMRを最も近い年齢グループに一致させます。
Example: A 50-year-old woman with a BMR of 1,620 cal/day has the metabolic profile of a 38-year-old. Her metabolic age is 38.
代謝年齢計算機 — 男性vs女性の結果
男性と女性のBMR基準線は異なります：
1
筋肉量：男性は平均30–40%多い筋肉を持ちます。
2
ホルモン：テストステロンは男性の代謝率を上げます。
3
体組成：女性は6–11%多い必須体脂肪を持ちます。
♀ 女性特有の変化
- Ages 35–45: Estrogen decline slows fat metabolism by up to 15%.
- Menopause: BMR drops an additional 200–300 cal/day for some women.
- Pregnancy: BMR increases by 15–20% to support fetal development.
♂ 男性特有の変化
- After age 30: Testosterone drops 1% per year — BMR falls with it.
- After age 50: Muscle loss (sarcopenia) accelerates — BMR drops 1–2%/year.
良い代謝年齢とは？
A good metabolic age is equal to or younger than your chronological age.
| Result | Meaning | Action |
|---|---|---|
| MA < real age | Excellent — faster metabolism | Maintain your habits |
| MA = real age | Normal — average metabolism | Small improvements help |
| MA > real age by 1–5 yrs | Below average — attention needed | Add resistance training |
| MA > real age by 6+ yrs | Poor — metabolism slowing fast | Immediate lifestyle changes |
5 Factors That Raise Metabolic Age
- ❌ Sedentary lifestyle (no exercise)
- ❌ Low muscle mass
- ❌ Chronic sleep deprivation (<6 hrs)
- ❌ High-processed-food diet
- ❌ Chronic stress and elevated cortisol
5 Factors That Lower Metabolic Age
- ✅ Resistance training 3–4 days/week
- ✅ High-protein diet (1.6–2.2 g/kg)
- ✅ 7–9 hours of sleep/night
- ✅ Slight caloric deficit consistently
- ✅ HIIT 20–30 min, 2×/week
How Is Metabolic Age Calculated on a Smart Scale?
Smart scales use Bioelectrical Impedance Analysis (BIA) to estimate metabolic age. BIA sends a small electrical current through your body to estimate lean body mass and fat mass, then calculates your BMR and compares it to age-group averages.
BIA accuracy depends on 4 conditions:
- 💧 Hydration level — dehydration inflates fat estimates by up to 10%
- ⏰ Time of measurement — morning readings before eating are most accurate
- 👣 Foot electrode positioning — uneven placement creates errors
- 🏃 Athlete vs non-athlete mode — most scales default to non-athlete algorithms
| Method | Accuracy | Cost |
|---|---|---|
| Online calculator (Mifflin-St Jeor) | ±5–8% | Free |
| Smart scale (BIA) | ±8–12% | $30–$300 |
| DEXA scan | ±1–2% | $40–$150/scan |
| Lab calorimetry | ±1% | $200–$400 |
Smart scale brands with metabolic age feature: Withings Body+, Tanita BC-533, Garmin Index S2, InBody H20N, Fitbit Aria Air.
BMI and Metabolic Age Calculator — Two Different Metrics
BMI (Body Mass Index) measures weight relative to height. Metabolic age measures how efficiently your body burns energy.
BMI formula: weight (kg) ÷ height² (m²). A score of 18.5–24.9 is normal.
3 Limitations of BMI:
1
Ignores muscle mass — a 220 lb athlete and a sedentary person can both show BMI of 28
2
Doesn't reveal metabolic health — normal BMI can coexist with a metabolic age 15 years older
3
Race and gender differences are not factored in
Use both metrics together. A healthy person targets: BMI 18.5–24.9 AND a metabolic age at or below their real age.
How to Lower Your Metabolic Age — 7 Proven Methods
1
Build Muscle with Resistance Training
Add 3–4 resistance training sessions per week. Each pound of muscle burns 6–10 extra calories daily at rest. Over time, 10 extra pounds of muscle raises your BMR by 60–100 cal/day.
2
Increase Daily Protein Intake
Eat 1.6–2.2 g of protein per kg of body weight daily. Protein has a thermic effect of 20–30% — meaning 30% of protein calories burn during digestion.
3
Improve Sleep to 7–9 Hours
Sleep deprivation raises cortisol, which breaks down muscle and stores fat. Just 5 nights of 6-hour sleep reduces insulin sensitivity by 25%.
4
Add HIIT 2× Per Week
High-Intensity Interval Training raises BMR for 14–24 hours post-workout — the afterburn effect. A 20-minute HIIT session burns 250–450 extra calories over 24 hours.
5
Cut Processed Foods and Refined Sugar
Processed foods spike insulin, promote fat storage, and reduce muscle protein synthesis. Replace 3 processed meals per week with whole foods to reduce metabolic age by 1–3 years within 90 days.
6
Stay Hydrated — 2–3 Liters Daily
Drinking 500 ml of cold water raises BMR by 24–30% for 60 minutes. Chronic dehydration slows metabolism and reduces exercise capacity.
7
Recalculate Every 90 Days
Track your metabolic age every 90 days. Muscle takes 8–12 weeks to measurably raise BMR. Regular tracking shows which habits actually work for your body.
よくある質問 — 代謝年齢
How to calculate metabolic age?
To calculate metabolic age, first calculate your BMR using the Mifflin-St Jeor formula. Then compare your BMR to the average BMR for each age group. The age group whose average BMR matches yours is your metabolic age.
How is metabolic age calculated on a smart scale?
Smart scales use BIA — a mild electrical current passed through your feet — to estimate lean mass and body fat. From these estimates, the scale calculates your BMR and compares it to age-group averages to produce a metabolic age score.
What is considered a good metabolic age?
A good metabolic age is equal to or lower than your real age. A metabolic age 5+ years below your chronological age indicates strong muscle mass, high activity, and efficient calorie burning.
How can I calculate my body age online?
Enter your gender, age, height, weight, and activity level into our free calculator above. The tool calculates your BMR using the Mifflin-St Jeor formula, compares it to age-group averages, and returns your metabolic age — no email required.
What is the difference between BMR and metabolic age?
BMR (Basal Metabolic Rate) is the number of calories your body burns at rest — it is a calorie number, not an age. Metabolic age is the age group whose average BMR matches your BMR. BMR is the input; metabolic age is the output.
Is metabolic age the same as biological age?
No. Metabolic age reflects calorie-burning efficiency. Biological age reflects cellular aging — DNA methylation, telomere length, and organ function. Both can differ from your chronological age, but they measure different things.
Can I improve my metabolic age naturally?
Yes. Resistance training, high-protein diet, quality sleep, and HIIT are the 4 most effective methods. Most people see a measurable improvement in metabolic age within 90 days.
What is a normal metabolic age for a 40-year-old woman?
A normal metabolic age for a 40-year-old woman is 38–42. A metabolic age below 35 indicates above-average metabolic health. A metabolic age above 48 signals a need for diet and exercise changes.
Why is my metabolic age higher than my real age?
A metabolic age above your real age means your BMR is lower than average for your age group. The 4 most common causes are low muscle mass, a sedentary lifestyle, chronic sleep deprivation, and a high-calorie processed diet.
Is a free metabolic age calculator accurate?
A free calculator using the Mifflin-St Jeor formula is accurate within ±5–8%. It is less precise than a DEXA scan but more accessible and useful for tracking progress over time. Accuracy improves if you include body fat percentage in the inputs.
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