Well, the "traditional" way is put the "my" variable in the scope of the loop.

#!/usr/bin/perl -w
use strict;
use 5.10.0;

## my $n; for (1..5) { $n++; say $n } ## wrong

foreach my $n (1..5) { say $n;}

__END__
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Update:
Maybe my previous example was not the best. But basically if you have something to initialize before a for loop starts iterating, do it in the for loop! "state" is actually a rather rare thing. You could code Perl for a year or two between using it.