Think heart attacks are a men’s issue saved for dramatic golf course scenes? Guess again. Heart disease is the leading cause of women’s death in the U.S., and even scarier, heart attacks are often difficult to detect in women because the early symptoms can be subtle. A new study by the National Institutes of Health—which surveyed pre-attack symptoms in women—reported that 70 percent of women experienced unusual fatigue a month or so before their attack, 48 percent experienced sleep disturbance and 42 percent had shortness of breath. A big key to prevention is remembering that you’re often your best doctor—if you feel “off” or generally unwell, always speak up.