Trying to send cURL in BASH more times -

i have bash script

for in {1..15}; curl ..here curl.. ; done 

for send curl every 1500ms , 15x not 1500ms,and not know how edit it, im doing bad ?

i order execute command every x seconds/milliseconds must somehow delay loop. using sleep easiest way it:

for in {1..15}   # non-blocking curl command here   sleep 1.5 done 

as default curl command block execution of loop , times between each loop iteration longer , not even. overcome need prepare curl command non-blocking.