Dr. Mike Fenster recalls the day when he received a real-life lesson on the importance of fast treatment.

 Two men arrived at the emergency room of the hospital where he was working at almost the same time.

 “One was a farmer who came in immediately after experiencing chest pains,” recalls Dr. Fenster, an interventional cardiologist. “The other man also had chest pains, but he waited for hours before deciding he should come in.”

The different decisions made by the two men affected them for the rest of their lives, NewsMax Health reports.

 “The farmer was able to return home the next day after appropriate treatment and go back to work quickly,” Dr. Fenster says. “The second man suffered permanent heart muscle damage.”

 Here are details on five conditions, including chest pain, for which prompt treatment is crucial, according to doctors.

CHEST PAIN:  90-minute window

 Chest discomfort should never be ignored, especially when combined with other symptoms.

The goal for the best outcome is to reverse symptoms within 20-30 minutes after the classic symptoms of chest pain combined with shortness of breath, or chest pressure. Other symptoms that may indicate that chest pain is the result of a heart attack include nausea, sweating, and pain radiating into the neck or shoulder or down the arm, [and] especially if moving around makes the symptoms worse.

 STROKE: 3-hour window

 When a person suffers an ischemic stroke caused by a blood clot, every minute counts. Every 60 seconds after a stroke, 2 million brain cells are lost.

 This can mean permanent paralysis or losing the ability to speak if a stroke is not treated in a timely fashion.

HEAD TRAUMA WITH LOSS OF CONSCIOUSNESS: 60-minute window

Actress Natasha Richardson refused medical help in 2009 after she fell and hit her head on a Canadian ski slope. She died at age 45 a few days later of an epidural hematoma.

Dr. Fenster says that even if there isn’t loss of consciousness, it’s a good idea to seek medical attention.

TETANUS: 72-hour window

Although tetanus infection is rare these days, it’s still better to be safe than sorry. The treatment is fairly benign, but the infection can be lethal.

 Tetanus bacteria survive in dirt and enter the body through breaks in the skin, usually deep cuts or puncture wounds from anything rusty, dirty, or from animal bites. If you haven’t had a tetanus shot within five years, be sure to get one promptly after suffering such an injury.

 DEEP VEIN THROMBOSIS: 2- TO 3-hour window

Deep vein thrombosis or DVT occurs when a blood clot forms, usually in the legs, and then breaks away and travels into the lungs, causing a pulmonary embolism.

“It’s marked by extreme pain in the legs and shortness of breath,” says Fenster.

 DVTs often occur when people sit for long periods of time, particularly during plane flights.