In the context of heart failure, which symptom might indicate fluid retention?

Swelling in the legs and ankles is a primary indicator of fluid retention, particularly in the context of heart failure. When the heart is unable to pump effectively, blood can back up in the veins, causing increased pressure that leads to fluid leakage into surrounding tissues. This accumulation manifests as edema, commonly seen in the lower extremities due to gravity's effect.

While insomnia, vision changes, and frequent urination can be symptoms associated with heart failure, they do not directly indicate fluid retention as clearly as swelling does. Insomnia may be related to discomfort or breathlessness, vision changes may occur due to inadequate blood flow or other complications, and frequent urination can be linked to the kidneys’ response to fluid overload, but none of these symptoms point to fluid retention with the same specificity as swelling in the legs and ankles.