PHP Sleep Is Breaking Foreach - php

Question

I have this following code:
<?php
$participants_db = "test_test_test_test_test_test_Sticky_Sticky_Sticky_Sticky_";
$participants = array_unique(explode("_", $participants_db));
foreach($participants as $user)
{
echo $user . '\n';
sleep(10);
}
?>
I spent hours debugging this script, it actually get each username and send email to each one,
the thing is it was sending emails for each user but $user didn't change... Im wondering Why Sleep Break the Foreach and How to fix this..
http://3v4l.org/b048m
UPDATE
here's the Full Code:
foreach($participants as $user)
{
if($user == '')
{
//echo 'broken';
break 1;
}
//get each user's email address
$sql3 = $dbh->prepare("SELECT * FROM users WHERE username = ?");
$sql3->execute(array($user));
while($a = $sql3->fetch())
{
$email = $a['email'];
$username = $a['username'];
}
$message = str_replace("{USERNAME}", $username.'_'.$user, $message);
sendemail($email, $cc, $from, $subject, $message, $filename, $filepath);
//sleep(10);
}
the array (participants) contains usernames , each user has different email address.
this script gets executed by a cron job. after the execution it sent emails to 2 emails (for example), and it's saying Hello Test_test to Both Emails That have Different Usernames
Im just wondering, how did it get the email and the username still the same???

Answer 1

The problem was str_replace
it replaced the {USERNAME} with a username, then after the exection $message doesn't contain {USERNAME} Which caused the main problem of it...