High blood pressure in overweight children has been linked to a stiffening of their arteries, placing them at greater risk of heart attack and stroke later.

Heart attacks could be decades in the making, with a new study linking high blood pressure in obese children to a stiffening of their arteries later in life.

A longitudinal study followed hundreds of children aged 11-19 in Finland for 27 years and showed risk factors for cardiovascular disease, such as obesity; high blood pressure; high cholesterol and insulin resistance in childhood and adolescence were linked with arterial distensibility - or stiffening of the arteries.

The elasticity of participants' arteries was measured using ultrasonography.

Arterial distensibility means the heart has to work harder to pump oxygenated blood through the body. It is associated with the "endpoints" of cardiovascular diseases, such as stroke and heart attack.

Cardiologist Professor Garry Jennings AO, chief of the Heart Foundation says the research adds to emerging evidence that shows what happens later begins to some degree in childhood.

"Kids don't get heart attacks, it's not a problem at the time, it's just that it's setting you on an adverse course later in life," Prof Jennings told AAP.

"Heart attacks don't just appear at the age of 35, 45 or 65, they've been decades in the making."

"It's just a question of how far back you go, just in the last few years an emerging science called epigenetics suggests that even experiences in the womb or very early life can program some of these risk factors for later in life," said Prof Jennings.

"And that's what this study tends to suggest."

The good news is that it's never too late to adopt a healthy lifestyle.

"We also know that at any age a healthy lifestyle with physical activity and good nutrition and having any of those risk factors managed properly can put the risk right back down to where it should be," Prof Jennings said.

The study was conducted at the Research Centre of Applied and Preventative Cardiovascular Medicine at the University of Turku, Finland and is published in journal Hypertension.