It’s one of those things I’ve always been able to do. I’ve done ti from time to time on a pairly regular basis. Apart from the fact that it feels pretty good to do I’ve never really noticed any direct benefits.
Has anyone done it long enough to actually know what the benefits are?
In some books risks are mentioned but not really what they might be. So, anyone know what the risks are?
I found this article pretty quickly on Google:
The article does state that it has quite a few benefits, and what they are claimed to be.
And this is the last paragraph:
I strongly recommend finding an experienced teacher to learn this "kriya"—cleansing. As potent as it can be to cleanse, the powerful vacuum created in the abdominal and pelvic cavities can also lead to disorders. The Pradipika states, "as taught by his Guru," and Sri Iyengar mentions that "it is not recommended for the average practitioner" and that Uddiyana should not be repeated for more than eight times at a stretch during a 24-hour period. In addition, those with heart disease, hypertension, or ulcers should not attempt it.
I personally have tried only the very beginning of it in a class given by an advanced practitioner. She warned that to learn the whole kriya one really does need a guru, but it was okay for us to practice this just for the class.
I have not attempted it because I know that I am not ready to learn something that advanced, and am a little averse to damaging my innards. 
Its not a very easy practice to master. Learning to isolate the rectii itself may take months.
[QUOTE=Joanna63;46265].
I have not attempted it because I know that I am not ready to learn something that advanced, and am a little averse to damaging my innards. :P[/QUOTE]
Isolating the muscles happaned by accident while sitting in a bathtub as a kid. It’s something I’ve known since then how to do. It was the rest of it that was new, to breathe out all the air and then control the muscles. I did show it to a teacher once, who was for all I know very good at it, and he thought I was doing it right, just that I needed to get rid of more air first (which I’ve done since then). I have never had any pains from it but I can’t say I’ve noticed any real benefits either.
Terje,
“Has anyone done it long enough to actually know what the benefits are?”
As with most of the yogic processes, every technique has far many more dimensions to it than what first appears on the surface. As with any other tool, it can be used in a million and one different ways depending on the kind of mind which is using them. If one is simply interested in physical health, that is fine. But it is not yoga, it is simply exercise. But as far as the work of the expansion of consciousness is concerned, all of these methods are just different skillful means to create an inner atmosphere which is prepared for transformation. A certain consistency in practice is needed if one is to unveil the deeper depths of most of these techniques. Otherwise, they remain simply superficial, neither are they capable of assisting one towards one’s liberation.
The various kriyas, if you practice them for sometime, one will find that it is not just the gross physical body which goes through a purification, but the subler levels of energy within one’s system. Fundamentally, they are for purification of the nadis to assist the awakening of Kundalini along the spinal cord.
Hm… I do practice asanas mainly as a way of keeping my body healthy. Or should I say healthier. I practice meditation but it’s not directly integrated with my practice of asanas. But I choose yoga as the main way to “workout” becasue I think it fits well into the rest of my life. In fact, once upon a time yoga was my way in to indian philosophy in general and buddhism in particular. Along the way I found out that yoga as a philosophical system wasn’t that interesting to me.
What am I trying to say here? Well, that I am aware of the other and perhaps deeper aspects of yoga than just doing asanas for physical health. I am not directly looking to awakening my Kundalini, I directly avoid any advanced pranayama, but I do think that the little yoga asanas I practice do help me in my life and my daily meditation practice.
I’ll keep on trying nauli for a while to see what it gives, trying to be aware on more than just a physical level.