Intermittent fasting may sound like another diet fad but researcher have conclusively found that the practice of routinely not eating and drinking for short periods of time resulted in longer life in heart patients.

In the study by Intermountain Healthcare Heart Institute in Salt Lake City, Utah, researchers found that heart patients who practiced regular intermittent fasting lived longer than patients who don't.

In addition, they found that patients who practice intermittent fasting are less likely to be diagnosed with heart failure.

"It's another example of how we're finding that regularly fasting can lead to better health outcomes and longer lives," said Benjamin Horne, principal investigator of the study.

While the study does not show that fasting is the causal effect for better survival, these real-world outcomes in a large population do suggest that fasting may be having an effect and urge continued study of the behaviour.

In the study, researchers asked 2,001 Intermountain patients undergoing cardiac catheterization from 2013 to 2015 a series of lifestyle questions, including whether or not they practiced routine intermittent fasting.

Researchers then followed up with those patients 4.5 years later and found that routine fasters had greater survival rate than those who did not.

Fasting affects a person's levels of hemoglobin, red blood cell count, human growth hormone, and lowers sodium and bicarbonate levels, while also activating ketosis and autophagy - all factors that lead to better heart health and specifically reduce risk of heart failure and coronary heart disease.

"This study suggests that routine fasting at a low frequency over two thirds of the lifespan is activating the same biological mechanisms that fasting diets are proposed to rapidly activate," said Dr Horne.

Researchers speculate that fasting routinely over a period of years and even decades conditions the body to activate the beneficial mechanisms of fasting after a shorter length of time than usual.

Typically, it takes about 12 hours of fasting for the effects to be activated, but long-term routine fasting may cause that time to be shortened so that each routine faster's daily evening/overnight fasting period between dinner and breakfast produces a small amount of daily benefit, they noted.

Fasting is not for everyone. Researchers cautioned that pregnant and lactating women should not fast, as well as young children and frail older adults.

People diagnosed with chronic diseases - especially those who take medications for diabetes, blood pressure, or heart disease - should not fast unless under the close care and supervision of a physician.