global or local declaration in a loop = inefficient?

Is there difference in speed/efficiency between the following two solutions?

local $foobar
for $i = 1 to 1000
    $foobar = "house"
    do_this_and_that...
next

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for $i = 1 to 1000
    local $foobar = "house"
    do_this_and_that...
next

____

note: I visually prefer to set the value inside the function instead than on the top in my real case because I need it in the middle of a long function....