It's a powerful thing when a life is saved, and that power has a way of spreading.

CPR helped save the life of Rudi Tanck, 63, of Naperville. So it's CPR his family is working to spread.

Through a series of at least five classes at their church, Knox Presbyterian in Naperville, the Tancks hope to train roughly 100 people in the lifesaving technique that helps keep the brain and organs alive when the heart is not functioning.

About 20 people came out to the third class in the series Thursday, less than three months after Tanck suffered a heart attack while visiting his son over Memorial Day weekend in Scottsboro, Alabama.

When Tanck collapsed, his wife, Joan, started CPR at the advice of a 911 dispatcher. She had learned the technique a long time ago as a Girl Scout and remembered enough to feel the compressions she was giving weren't quite working.

So the couple's son, Brian, took over. His CPR training was more recent, having come eight months ago during a course he attended at the church where he and his wife are co-pastors.

Tanck learned later on that his son performed CPR for roughly eight minutes before emergency medical technicians arrived and took over.

"I can't imagine doing anything that intense for that long," he said.

The rest of Tanck's lifesaving story involved an off-duty emergency medical technician arriving with needed supplies, a newbie ambulance driver making what typically would be a 45-minute drive to the closest hospital in only 30 minutes, and about a week in hospital care.

Now the marketing manager for Ryerson, a metal processing and distribution company in Lisle, is back to work full time and feeling healthy. In fact, one of the first things he did when he returned home to Naperville about two weeks after the heart attack was take a leisurely bike ride.

"It's all about the power of prayer, miracles and support," Tanck's wife said. "Everyone's been so supportive."

Deacons at Knox Presbyterian, including Leslie Elliott, see themselves as caregivers for the congregation, Elliott said. And they're helping cover the cost of the CPR classes for church members who sign up. The classes cost $20 to participants.

Joan Tanck hopes people get trained so they know how to act when a life is in the balance.

Those who attend upcoming classes Sept. 19 and Oct. 17 will not become CPR-certified but will learn the principles of the technique and how to use an automatic external defibrillator. These actions can give a cardiac arrest or heart attack sufferer a greater chance at survival, said Amanda Hunt, system manager of simulation and training for Edward-Elmhurst Health.

The main teachings are to act -- not to freeze out of fear -- and to give rhythmic, 2-inch-deep chest compressions, aiming for 100 to 120 a minute.

"What am I going to do while 911 is coming," Hunt said. "Just jump on the chest hard and fast. Do the best you can until someone arrives."

Giving good CPR can be draining, so Edward Hospital trainers suggest bystanders take turns every two minutes, if possible.

"You really become the pump for the heart when you do CPR," Hunt said. "It is very exhausting."

Getting trained, however, is less intensive, requiring a two-hour commitment for the type of course that does not result in certification.

To register for a course at Knox Presbyterian, call the church office -- staffed by office manager Joan Tanck herself -- at (630) 355-8181.

For details about other CPR training courses offered through Edward Hospital, call the training center at (630) 527-3596 or visit https://www.eehealth.org/classes-events/cpr-first-aid/.