I have practiced Zen meditation for several years. I'll start with the health and psychological benefits first.
1. Breathing is the whole key to good meditation in my experience. By mastering our breathing in meditation, blood pressure goes down, and stress
hormones dissipate. I myself have high blood pressure. I still need to take medication for it since it's pretty aggressive, but I need to take much
less medicine than otherwise indicated because of the meditation.
2. In the Zen tradition, the object of meditation is not our thoughts but our breathing. As we focus on breathing, we take notice of the hundreds of
thoughts and worries that trouble us during the day. With practice, these thoughts come to surface but than settle themselves down much more quickly.
Through this, it's much easier to examine our own psychological well being (when not meditating) because we are not confused by all the thoughts
that normally distract us.
For many practitioner's of Zen meditation, these physical and psychological benefits are enough, and there's nothing really wrong with that. For
others like myself, who sought out Zen as a means of reaching "enlightenment", than it becomes something more. Of course it's impossible to define
what exactly enlightenment is, and it seems like the more I obsessed about reaching enlightenment, the more frustrated I got. Instead I've come to
just work on my breathing and
koan.
I don't think there are any risks to meditation per se. When a person becomes adept at meditation they may experience what is called "makyo" in
Japanese. These are a kind of hallucination, although not as dramatic as that. Sometimes you may hear something that's not there, or even see
something. It's nothing to worry about. It's actually an indication that your mind has become still enough that this extraneous stuff from your
sub-conscious is breaking through. If you're not with an experienced Roshi, it can bewildering, but there's no harm in it. It's just an illusion,
not real.
I was lucky to find a good Roshi early in my path. It can make all the difference. A good teacher will correct your beginning mistakes and make your
meditation more fruitful. Good luck!
