Big drop in heart attacks follow smoking bans

How harmful is secondhand smoke? Nonsmokers have a 25 percent to 30 percent higher risk of heart attack if they inhale smoke at home or at work, and smoke has been shown to affect heart health within minutes, says Meyers.

"We can measure chemical changes within 20 minutes," he says. "The changes that occur primarily involve the clotting system. Basically, exposure to smoke makes your blood sticky and real clot-y and that's what causes heart attacks." Health.com adds that social smokers aren't just hooked on nicotine, either.