Researchers found that stroke patients gained about two days of healthy life for every minute spared between the onset of their stroke and when they first received treatment, on average.
"Every 15 minutes you wait, you lose a month of life," Dr. Atte Meretoja told Reuters Health.
Meretoja is the study's lead author from the Melbourne Brain Centre at the Royal Melbourne Hospital in Parkville, Australia.
The exact ratio of saved treatment time to healthy days varied by patient, he and his team found.
Although it's well known that early treatment for strokes is best, the new study helps highlight how significant even small delays can be, researchers said.
"We developed that measure so it's easy to remember and that the general public will understand it," Meretoja said.
He and his colleagues summarized their findings in the journal Stroke as, "Save a Minute, Save a Day."
There is currently only one treatment approved by U.S. regulators for ischemic strokes, which are caused by blockages in blood vessels going to the brain. Usually, the blockage is a result of clotted blood or fatty deposits known as plaque.
Thrombolysis is the use of a drug known as tissue plasminogen activator, or tPA, to break up the blockage and allow blood to flow to the brain. Restoring blood flow prevents the death of brain cells and improves people's recovery.
The treatment is time sensitive, however. The 60 minutes from the onset of a stroke is often referred to as the "golden hour" for treatment, because people treated during that time have much better odds of completely recovering.
Approximately 800,000 people in the U.S. have strokes every year, according to the Centers for Disease Control and Prevention. About 87 percent of those are ischemic strokes.
For the new report, the researchers compiled data from two studies to find how time to treatment is related to how patients fare after a stroke.
The studies, from Finland and Australia, included 2,258 stroke patients.
On average, the researchers found that patients gained 1.8 disability-free days for each minute shaved off the time to treatment.
Middle-aged stroke patients tended to gain about three days per minute saved, while elderly patients gained one day or less.
"The magnitude of benefit here is very much aligned with previous data and analyses we've done looking at the benefits," Dr. Gregg Fonarow, who was not involved with the new study, told Reuters Health.
Fonarow is co-chief of the University of California, Los Angeles Division of Cardiology.
"Time is really the most critical factor here in determining the outcome," he said.
Over time, Fonarow said hospitals have improved the time they take to get patients treatment. But there has been little success in shortening the time it takes for people to recognize they're having a stroke and get to a hospital.
Many organizations promote the FAST pneumonic device to remember the symptoms of a stroke: Face drooping, Arm weakness, Speech difficulty and Time to call 9-1-1 after any symptom.
"We continue to need to strive to educate the population regarding the benefits of seeking care as quickly as possible after suspecting stroke," said Dr. Robert Brown, a stroke specialist at the Mayo Clinic in Rochester, Minnesota.
Brown, who was not involved with the new study, said the finding that every minute counts is also a reminder to doctors and medical staff to evaluate their practices in an effort to save time once the patient arrives at the hospital.
"I think this is also very enlightening and energizing to providers who are constantly thinking of ways to improve," he said.