Heart disease is the No. 1 killer of women, and each year more women than men die from heart and cardiovascular disease without ever realizing they are at risk.

"After having a heart attack, a woman's chance of not surviving the first year or having another heart attack is greater than a man's," says University of Alabama at Birmingham cardiologist Alan Gertler, M.D. Preventing a heart attack, he says, is a critical objective.

Gertler says all women are at risk for heart disease, and the risk rises substantially as they age. "The incidence of heart disease among women overtakes men when they reach their late 50s, usually about five to 10 years after menopause," he says.

Gertler says one reason could be that biological changes tied to menopause may cause a dip in good cholesterol, predisposing them to clogged arteries. And though hormone-replacement therapy can reduce the symptoms of menopause, he says studies have produced differing results about whether or not it is beneficial for a woman's heart.

Sleep deprivation, stress and a confused circadian clock can be a lethal combination  

Heart disease is the No. 1 killer of women, and each year more women than men die from heart and cardiovascular disease without ever realizing they are at risk.