In the earliest stages of heart failure, your symptoms may be mild. You may feel tired easily, be short of breath when you exert yourself, feel like your heart is pounding or racing (palpitations), feel weak or dizzy, and have an increased heart rate. 

As heart failure gets worse, fluid starts to build up in your lungs and other parts of your body. This may cause you to: 

  • feel short of breath even at rest 
  • have swelling (edema), especially in your legs, ankles and feet 
  • gain weight (over just a day or two, or more slowly) 
  • cough or wheeze, especially when you lie down need to urinate more at night 
  • feel bloated or sick to your stomach. 

If your symptoms suddenly get worse, you will need emergency care.