4 signs you have heart failure that you probably don't know, including those more likely to affect women

• Heart failure happens when the heart can't pump enough blood and oxygen to other organs.
• Early, subtle symptoms of failure can be "harbingers" of death, the American Heart Association says.

Heart failure can cause early, subtle symptoms that can be "harbingers" of the disease worsening and impending death, according to a report from the American Heart Association.

The report, published on Thursday in the medical journal Circulation, outlines the most recent knowledge on the symptoms of heart failure, as well as other cardiovascular diseases, including stroke.

Heart failure happens when the heart can't pump enough blood and oxygen to other organs. It can be fatal. Heart failure can't usually be cured, but early treatment can help people live longer with a better quality of life, according to the Centers for Disease Control and Prevention. Treatment involves drugs, physical activity, and cutting down on salt in the diet.

About 6.2 million US adults have heart failure, according to the CDC.

Smoking cigarettes, drinking excessive amounts of alcohol, insufficient physical activity, and a poor diet — that's too high in salt, fat, or cholesterol — all increase the risk of heart failure. Medical conditions, like heart disease, previous heart attacks, high blood pressure, obesity, and diabetes also increase the risk of getting it.

Heart failure most often causes breathlessness

Breathlessness is a "hallmark" feature of heart failure, the report said. Severe breathing problems are linked with an increased risk of death, the American Heart Association said.

The report said other health conditions that cause breathing problems, like chronic obstructive pulmonary disorder, can co-occur with heart failure.

Other common symptoms of heart failure include generally feeling tired, and swollen feet, legs, or ankles, according to the CDC.

The American Heart Association report said fatigue was the most "bothersome" hallmark feature of heart failure.

Early heart-failure symptoms include nausea

Early symptoms of heart failure include an upset stomach, nausea, vomiting, and appetite loss, the report said.

Muscle wasting as a consequence of heart failure can indicate that the disease is progressing to more advanced stages, it said.

The report added: "Early and subtle symptoms also can be harbingers of worsening HF and impending hospitalization or death."

Other heart-failure symptoms include insomnia, depression, and anxiety

The review found 25 to 30% of adults with heart failure reported mood disturbances — mostly depression and anxiety — as well as insomnia.

Heart failure causes insomnia for a number of reasons. Firstly, people with heart failure often get breathless when lying flat. Secondly, a side effect of heart-failure drugs can make people pee more during the night because the medication off-loads fluid that accumulates in the lungs, which causes breathlessness, and lower extremities, which causes swollen feet.

Women with heart failure are more likely to get an upset stomach

The report said women with heart failure were more likely than men to report nausea, heart palpitations, an upset stomach, sweating, swelling, pain, depression, anxiety, and a lower quality of life.

Heart failure is diagnosed at a later age in women, and women can have more concurrent illnesses, which may partly explain these differences, the American Heart Association said.