A new study has found a possible link between singing "Amazing Grace" and improved heart health. 

The study was carried out by researchers at the Medical College of Wisconsin to find out what effect singing the much-loved hymn might have on the cardiovascular health of older people with coronary heart disease, Premier Christian News reports.

Participants in the study were asked to sing two songs out of a selection of "This Land Is Your Land" by American folk singer Woody Guthrie, the Beatles' "Hey Jude", "Jolene" by Dolly Parton, and the hymn "Amazing Grace". They had to sing their chosen songs for 10 minutes each.

The researchers measured vascular function before and after each singing period, and found that "Amazing Grace" had the largest effect size (22.3%), while the folk song "This Land Is Your Land" had the least (10.1%). 

The researchers stressed that while the size of their study - 65 people - meant it was a "strictly exploratory analysis", the findings "might be hypothesis-generating" for future research in music medicine. 

The study concluded, "Singing should be considered as an accessible and safe therapeutic intervention in an older population who otherwise may have physical or orthopedic limitations hindering participation in traditional exercise." 

"Amazing Grace" was written in 1772 by former slave trader John Newton who converted to Christianity and became an Anglican clergyman. The hymn remains a staple in church services today and is popular even among non-Christians.