I'm a Christian and meditation in Christianity is not approved! so I do not meditate !!!
There are many different tradition and applications as it relates to what is referred to as meditation. Practice itself does not necessarily have to be connected with a spiritual belief system, but understood or applied from the context of psychology and neuroscience.
Catholics have a meditation tradition called contemplative prayer. Eastern Christian and Jewish tradition has a rich meditation history also.
Practically:
- a scary movie can increase your heart rate
- loud music or a crafty salesmen can hinder focus
- a quiet environment can improve concentration
- mental visualization can produce certain feelings
- deep breathing and relaxation techniques are scientifically proven to reduce stress
What you think about can affect your mood.
- be careful for nothing
- don't live anxious
- practice self-control
- practice moderation in all things
In a poker environment, a little calm can be helpful to make clear decisions. As when we cut the music down in the car when looking for an address in an area we are unfamiliar with.
I don't know if poker is a Christian approved activity. Yet, all things are lawful unto me but not expedient. I will not be brought under the power of anything.
I would not recommend anything your faith is uncomfortable with, but you may already at times practice what some refer to as meditation, in your own way, just not as a formal discipline from a defined tradition.