Which factors can increase water requirements in patients?

Increased water requirements in patients can be attributed to factors that cause greater fluid loss or increase metabolic needs. Hot weather contributes to dehydration through increased perspiration. Exercise elevates respiration and perspiration rates, causing the body to lose more water. Fever and illness can lead to further fluid loss through sweat, respiratory rates, or gastrointestinal symptoms, such as vomiting or diarrhea. Lastly, excess fluid losses, such as those from sweating or wounds, directly increase hydration needs to maintain homeostasis and support bodily functions.

The other factors listed, while relevant to hydration, do not typically result in an overall increase in water requirements to the same extent. Cold weather may reduce fluid loss through sweating, and a high-protein diet does increase water needs slightly, but not to the same degree as the factors outlined in the correct choice. Aging and low physical activity might lead to less water requirement due to lower energy demands.