I shall start this post by putting forth that I don't subscribe to any organised religion. I consider myself an atheist but I enjoy reading into specific religions and taking from them what I consider useful or beneficial. That said, I do think they can do harm when people swallow wholesale the doctrine of one case or the other but i'm not here to argue the case for or against religion as a whole, not today anyway.
With regards to Christianity, I used to think that prayer was a totally futile endeavour. I didn't believe in god so I didn't see why people would get any benefit from conversing with him. Then I discovered meditation. I practice meditation pretty much daily and for me it has a hugely positive effect. I don't think this has anything to do with spirituality or mysticism, for me its purely scientific. Focusing your mind creates neural pathways for concentration. The more you meditate, the more you strengthen these pathways. For me its purely a chemical process. I also believe focusing on breathing helps regulate it and breathing through the nose instead of the mouth has proven medical advantages as the air is basically filtered through the nasal passageways. So anyway, how does this relate to prayer. Well consider what prayer is. The subject sits, tries to block out all other thoughts and repeats a saying or phrase. Whether they believe that anyone is listening is not the point. Many feel that their life improves afterwards and attribute this to god listening. I attribute it to the fact that they are implementing a daily, strictly adhered to, mindfulness practice in their life. They are, for all intents and purposes, meditating.
As a final note, I genuinely believe that most religion stems from a common point. As such the idea that meditation crops up in the Christian faith, albeit through a subtle means, is not surprising to me.