Researchers warn that many young women know little about the risks they face of cardiovascular or heart disease. But a new study suggests women may be able to reduce those risks by doing light physical activity as they age. Heart disease remains the top cause of death for women in the United States. Yet only one in 10 young women reported knowing that fact. And fewer than one in 20 believed heart disease was the leading health problem for women. These are the findings of a study that questioned 331 women between the ages of 15 and 24 about heart disease. The study asked women what they knew about heart attacks and heart failure, and how to prevent them. The researchers then compared the results to a 2012 opinion study of 1,227 women above age 25. The Journal of the American Heart Association published the recent findings earlier this month.