Unexplained drop in resting heart rate increases heart disease risk By (0) An unexplained drop in resting heart rate as a child can increase risk for later development of heart failure and heart disease. Photo by Semevent/Pixabay Children who have a sudden lowering of their resting heart rate as they move into young adulthood may be at increased risk for heart disease later in life, researchers report. For their new study, they assessed data from 759 Black and white participants in the Augusta Heart Study, which was designed to evaluate the development of risk factors for heart disease. Advertisement It followed young participants in the Augusta, Ga., area, who were healthy and aged 5-16 at the time of enrollment, as they grew into adulthood.