And here's something else to help a skittish bystander choose to do something rather than nothing. In a major change to traditional CPR, the American Heart Association says mouth to mouth breathing which makes some people uneasy in many cases is not needed.
"It's pretty radical and yet it's something we now know is very effective," said Dr. Stephen Archer, cardiologist, University of Chicago Medical Center.
That means if a person collapses in front of you chest compressions alone may be enough until professionals arrive. During a recent CPR class at the State Bank of Countryside that news was a relief to many participants.
"I would definitely be more willing to do this," said Vicki Borsilli, CPR training participant.
"The chest compressions definitely just doing that makes it a lot easier," said Anne Ronstadt, CPR training participant.
Why the change? It's not just about making bystanders less uneasy.
Newer research is showing hands-only CPR is just as good and possibly better than traditional CPR.
One reason is that some doctors say is that stopping hand compressions to do mouth to mouth tends takes much longer than recommended.
"While the breathing might be nice in principle and you are in a hospital that's different. But in the community it's just the compression of the chest that's actually giving you the pressure and blood supply to the brain," said Dr. Archer.
Pushing hard and fast on a person's chest helps move blood still rich with oxygen through the body helping sustain life and prevent brain damage which can happen in a matter of minutes.
"They called the priest and he gave me last rites," said Cheri Kalas. But 52-year-old Oswego High School teacher Cheri Kalas was one of the lucky ones. Two years ago when she was about to begin a 5K charity run she collapsed.
A married couple also running the race performed CPR. Another bystander got hold of a defibrillator and they kept Kalas' heart going until an ambulance arrived. Kalas says despite the odds she suffered no permanent damage. She credits the brave bystanders who were willing to try CPR.
"You are saving somebody's mother somebody's father, brother, sister, somebody's somebody," said Kalas.Traditional CPR is still recommended in other cases, especially for children and adults who may have been involved in a near drowning or drug overdose. Not everyone in the medical community is convinced compression-only CPR is better and some would like more research before endorsing it.