Diuretics are often used in sports to.

Diuretics are often used in sports primarily to mask other drugs. By promoting increased urine production, diuretics can help athletes eliminate substances from their bodies more quickly, making it harder to detect performance-enhancing drugs during testing. This ability to flush out drugs can present an athlete with a way to avoid detection and is a well-documented abuse within various competitive environments, especially where strict drug testing is enforced.

The other options do not accurately reflect the primary purpose of diuretics in the context of sports performance. For example, while they might lead to temporary weight loss or decreased body fluid, they do not enhance muscle growth, increase endurance, or boost mental focus as a mechanism of action. Diuretics could potentially lead to impaired performance due to dehydration or electrolyte imbalances, further establishing that their use is primarily associated with subterfuge in drug policies rather than legitimate performance enhancement.