1. What is Total Body Water?

Total Body Water (TBW) is the total amount of water in the human body. It accounts for approximately 50-60% of body weight in adults, with variations based on age, sex, and body composition.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Weight \) — Body weight in kilograms
• \( Age \) — Age in years
• 0.6 — Base water percentage
• 0.003 — Age adjustment factor

Explanation: The formula accounts for the decrease in body water percentage with age, starting from about 60% in young adults and decreasing by approximately 0.3% per year.

3. Importance of TBW Calculation

Details: Knowing total body water is important for fluid management, medication dosing, nutritional assessment, and understanding body composition.

4. Using the Calculator

Tips: Enter weight in kilograms and age in years. All values must be valid (weight > 0, age between 0-120).

5. Frequently Asked Questions (FAQ)

Q1: How accurate is this calculation?
A: This provides a general estimate. More accurate methods include bioelectrical impedance analysis or dilution techniques.

Q2: Does TBW vary by gender?
A: Yes, women typically have a lower percentage of body water than men due to higher body fat percentage.

Q3: Why does TBW decrease with age?
A: Aging leads to increased body fat and decreased lean muscle mass, both of which affect water content.

Q4: How does this compare to the Watson formula?
A: The Watson formula is more complex and considers gender and height, potentially providing more accurate estimates.

Q5: When would I need to know my TBW?
A: TBW is important for medical treatments involving fluid balance, dialysis, and certain medication therapies.