Pulmonary Embolism On Serena Williams?

Pulmonary embolism in a world-class athlete like Serena Williams is so unbelievable that I thought the news about it went all wrong, but it really happened.  Doctors always say that sedentary people have more chances to get it so if this has happened to Serena Williams who is a top athlete, what are the chances of people whose form of exercise is to walk a few steps from the TV to the refrigerator or those who'd rather sit it out in front of TV or computer than do a bit of walking for at least 10 minutes everyday.