New York, US (BBN)-Age is just a number - so goes the old adage.
But, it may not be a very telling one, scientists investigating heart age have warned.
For while millions of us may feel young at heart, the reality is likely to be quite different, reports The Daily Mail.
A new study has found almost three in four people have a heart that is older than their chronological age.
The average American man's heart age is nearly eight years higher than his actual age, while the average US woman's heart is five-and-a-half years old, according to a report by the Centers for Disease Control and Prevention.
Heart disease is the world's leading cause of death, killing 17.5 million people in 2012.
It is responsible for one in every four deaths across the UK and US.
CDC researchers used the Framingham Heart Study test to produce the nation's first picture of heart health.
The test takes into account a person's health, including their blood pressure and whether they suffer diabetes, as well as lifestyle factors, such as whether they smoke and if they are obese.
Experts warn, their findings mean vast swathes of the population are at heightened risk of heart attack or stroke.
One in four deaths in the US and UK each year is due to heart disease, while many result from heart attacks and strokes.
'This is alarming. Heart disease is the nation's number one killer,' said the report's lead author, CDC scientist Quanhe Yang.
'But the bottom line is you can do some very simple things' to become younger at heart, he said.
The CDC scientists estimated the average 'heart age' of men and women in every state, based on risk factors including high blood pressure, obesity, and whether they smoke or have diabetes.
Then they compared the numbers to participants' average actual ages.
The nation's heart disease death rate has been falling thanks to advances in prevention and treatment, including drugs to control blood pressure and lower cholesterol.
But heart disease remains America's leading cause of death.
The average age of first heart attack is about 64 and a half for men and 72 for women, according to the American Heart Association.
Health officials have been pushing to get more people to control their weight, quit smoking and take other steps to help their heart and blood vessels.
The CDC is leading a 'Million Hearts' campaign, launched in 2012 to prevent one million heart attacks and strokes by 2017.
CDC scientists were intrigued by a heart age calculation developed by other researchers conducting a large study in Framingham, Massachusetts.
Some research has indicated that Framingham heart age calculations have resonated more with patients than more conventional medical advice and warnings, so CDC researchers used the Framingham model - and CDC national survey data - to produce the first report on heart age across the nation.
CDC officials released the report on Tuesday.
'It gives a stark, simple picture of your future risk of having - or dying from - heart attack or stroke,' said CDC Director Dr Tom Frieden.
The estimates were specific to adults aged 30 to 74 who have not had a heart attack or stroke.
Mississippi has the highest proportion of adults with advanced heart age, followed by West Virginia, Kentucky, Louisiana and Alabama, the report says.
Those states also have higher rates of smoking, obesity, and other heart disease risk factors.
Meanwhile, Utah and Colorado have the lowest proportions of people with a heart age five years or greater than their actual age, followed by California, Hawaii and Massachusetts.
The study also reveals that for African-American men and women nationally, heart age is 11 years greater than their actual age.
The gap, however, is much smaller for whites and Hispanics.
On Tuesday, CDC officials also shared the Framingham study's online heart age prediction calculator for individuals to assess themselves.
People have to know their systolic blood pressure - the higher of the two measurements - to generate an estimate.
BBN/SK/AD