This guide explains how exercise changes your tdee short-term and long-term using widely referenced CDC and WHO standards. It is written as plain-language education to help you interpret your own measurements — not as a substitute for personalized medical advice.
About How Exercise Changes Your TDEE Short-Term and Long-Term
Basal Metabolic Rate (BMR) is the calories your body burns at complete rest to keep you alive — breathing, circulation, and cell repair. Total Daily Energy Expenditure (TDEE) adds the energy of daily activity, digestion, and exercise. BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + s, where s is +5 for men and −161 for women. This Mifflin–St Jeor equation is the most validated modern formula.
From BMR to a daily calorie target
Multiply BMR by an activity factor to estimate TDEE. A moderate deficit below TDEE (about 10–20%, or roughly 300–500 kcal/day for many adults) supports gradual fat loss while preserving muscle; a small surplus supports muscle gain.
- 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
- Extra active (physical job + training): BMR × 1.9
Recalculate as your body changes
BMR falls with age and with weight loss, so revisit your numbers every few months or after significant changes in weight, training, or life stage. Treat TDEE as an estimate to adjust against real-world results over weeks.
Try Our Free Calculators
Want to run the numbers yourself? Use these free tools: