Apparently I don't have enough points to comment on the accepted answer, so I'll try posting an answer directly. I know this is a very old question and PLE is somewhat less used than 8 years ago but this question still comes up in search results. I think you guys are speaking a different language in the accepted answer. cntr_type column is a bigint - it's never going to be a decimal. The value ssd_rider is seeing in the column is 46000. Europeans and Americans place the thousands divider differently. I find in technical discussions it's best not to place them at all.

To answer the actual question, PLE will increase by 1 second each second that you are not forcing stuff out of memory. It is a live counter, so it will go up forever if you just do 1 select and then leave your server sitting there doing nothing. As you indicated this is a test server that's likely what will is happening. So don't be alarmed by big numbers in PLE, particularly in inactive systems. That is expected and indicates no memory pressure.

If the value was 46 that would be a very low value. Generally you want to keep things about 75 per GB of memory SQL has, but even if you see it low - don't panic. Go read some comments from some of the top SQL guys and they'll suggest looking to wait stats for a more relevant metric to use when troubleshooting.