This stretched muscle contracts more forcefully, much as an athlete's muscle stretched before exercise does. This is one of the heart's main mechanisms for increasing its performance in heart failure. Where the fluid accumulates depends on the amount of excess fluid held in the body and the effects of gravity. If the person is standing, the fluid sinks into the legs and feet. If the person is lying down, the fluid usually accumulates on the back or in the abdomen.
Weight gain caused by the body's retention of sodium and water is common.
The enlarged heart muscle can contract with greater force, but eventually it malfunctions, making the heart failure worse. Symptoms People with uncompensated heart failure feel tired and weak when performing physical activities because their muscles aren't getting an adequate amount of blood. The swelling also causes many symptoms. Besides being influenced by gravity, the location and effects of swelling are influenced by which side of the heart is predominantly impaired. Although disease on one side of the heart always causes failure of the whole heart, the symptoms of disease on one side or the other often predominate.