However new research published in the journal Stroke, from the American Heart Association, found that reducing delays by just a few minutes could lead to big gains.
Researchers said that across the entire sample of more than 2,200 people "each 15 minute decrease in treatment delay provided an average equivalent of one month of additional disability-free life."
"'Save a minute, save a day' is the message from our study, which examined how even small reductions in treatment delays might benefit patients measurably in the long run, said Dr Atte Meretoja, lead author of the study and associate professor of neurology at the University of Melbourne.
"Clot-busting treatment works equally well, irrespective of race, ethnicity or gender.
"Speedy restoration of blood flow to the brain is crucial for brain cell survival everywhere."
Data for July to September 2013 shows that it took an average of two hours and 25 minutes for stroke victims in England to receive clot-busting drugs from the onset of their symptoms.
The typical time it took from a patient arriving at hospital to receiving the drugs was 59 minutes.
However in Helsinki, Finland and Australia the average time is just 20 minutes from hospital arrival to start of treatment.
Researchers found that people who were aged 80 and had suffered a severe stroke could get half a day of healthy living extra for every minute of reduced delay in getting treatment.
Those the same age with a mild stroke could enjoy almost a full extra day while those aged about 50 with a mild stroke would gain almost six extra days.
The rest is here:
Stroke survivors lose a month of healthy life for every 15 minute delay