If your variables have utterly different names and completely different purposes, which prevents from putting them into one array, you might want to use something like

{
   no strict 'refs';
   my @incs = qw( index chapter index pages names );
   for my $i (@incs) {
      ${"total_$i"} += $$i;
   }
}
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It would still be better if you first built up an hash with hard references and then iterate through the command list

my %incs = (index   => [ \$index,   \$total_index ],
            chapter => [ \$chapter, \$total_chapter ],
            pages   => [ \$pages,   \$total_pages ],
            names   => [ \$names,   \$total_names ] );
my @incs = qw( index chapter index pages names );
${$incs{$_}->[1]} += ${$incs{$_}->[0]} for (@incs);
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This does not violate use strict (assuming that you have declared all your variables before);