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TBW 60% Males — FRCA Primary MCQ

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EasyPhysiology - RenalTBW 60% MalesFRCA Primary

Total body water in a 70 kg adult male is approximately what percentage of body weight?

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Correct answer: E — 60%

Total body water (TBW) is approximately 60% of body weight in adult males (42 L in 70 kg). It is lower in females (~55%) and elderly (~50%) due to higher fat content. TBW is distributed: intracellular fluid ~2/3 (28 L) and extracellular fluid ~1/3 (14 L). ECF divides into: interstitial (11 L) and plasma (3 L).

Reference: Power Kam 2018 Principles of Physiology for the Anaesthetist