Which percentage of body weight loss is associated with physical and mental decrement?

• A. 2% of body weight
• B. 5-10% of body weight
• C. 10-15% of body weight
• D. 15% or more of body weight

Answer: (C)

Loss of body weight from dehydration disrupts fluid balance, reduces plasma volume, and raises core temperature, all of which blunt both physical and cognitive performance. When fluid loss reaches about 10-15% of body weight, these systemic stresses become substantial enough that you see clear, cross-cutting decrements: strength, endurance, and motor coordination decline, while mental functions such as concentration, reaction time, and decision-making deteriorate. This threshold represents where the combined physical and cognitive effects are readily noticeable in most individuals. Lower losses can impair performance to some degree, but the parallel drop in both body and mind is most evident in the 10-15% range.