First let me say something about "breathing method" of China.
More than twenty years ago, my uncle heard that I was weak in health, and hence he mailed my mother a book about "breathing method".
"Breathing Method" is to use our conscious mind to control the rate of breathing. Normally, our breathing rate is NOT controlled by us. When we do strenuous work or exercises, our breathing rate will AUTOMATICALLY be increased. When we relax, or when we do not have to exert ourselves, our breathing rate will decrease. But "Breathing Method" teaches us to control the rate consciously. And some would decrease their breathing rate to 1 or 2 times per minute.
Also "Breathing Method" stresses on a healthy state of mind too. For example, one would say repeatedly in our mind "I should be kind, I should be kind, I should be kind, .... "
After I have gotten the book, I practiced it according to what it says. Sure, after several months, I gained weight a lot, (about 20 pounds in several weeks).
But I also discovered that if I do not practice it, my weight will decrease to my usual level!
It is much like "body building". A person can make himself very muscular by lifting weights, etc. But when he doesn't use his muscle, his muscle will become weak as normal. Hence he must keep on exercising to maintain that state.
After some length of time, about 20 years, the method didn't work for me. I just do not know why. I did not gain weight even if I practiced that.
Then I forsook "controlling my breathing rate", and let my body does it automatically for me.
Once I was ill on bed, and had a high temperature. My breathing rate increased and my body became hot. I did not control my breathing rate, it increased automatically. After some days, I recovered, (I did not take in medicine. Usually my illnesses will cure itself in one week's time, or sometimes 2 weeks. I observe that small children also recover in one week's time.)
From that time onwards, I never wasted my time on "breathing exercises". I think LORD design our body in a very ingenuous way. Our body weight will adapt to our needs. Our body is optimal for our present needs.
I once saw a boy of about 15, who was weak in health, but because his father died, and he had to work in a factory, engaging himself in heavy lifting work. To my surprise, I saw him become very muscular after some months.
Hence I know that LORD will give me strength when I need it.
Jesus : "Therefore I tell you, do not be anxious about your life, what you shall eat or what you shall drink, nor about your body, what you shall put on. Is not life more than food, and the body more than clothing? Look at the birds of the air; they neither sow nor reap nor gather into barns, and yet your heavenly Father feeds them. Are you not of more value than they? And which of you by being anxious can add one cubit to his span of life? And why are you anxious about clothing? Consider the lilies of the field, how they grow; they neither toil nor spin; yet I tell you, even Solomon in all his glory was not arrayed like one of these. But if God so clothes the grass of the field, which today is alive and tomorrow is thrown into the oven, will he not much more clothe you, O men of little faith? Therefore do not be anxious, saying, 'What shall we eat?' or 'What shall we drink?' or "What shall we wear?' For the Gentiles seek all these things; and your heavenly Father knows that you need them all. But seek first his kingdom and his righteousness, and all these things shall be yours as well. [Mt 6:25-33]
Hence we should spend our time in seeking the kingdom of LORD and the righteousness of LORD, e.g. helping the poor and needy, orphan or widow, OR help them to walk in the way of LORD, by preaching the teachings of LORD and Jesus, OR .....
One should not put too much emphasis on our "body", and spend hours practicing "Falon Gong".
This has one danger too : What if you "body" or even your "life" is being threatened/blackmailed ? Would you hold fast onto death the teachings of LORD and of Jesus, and anxious not about your "body"?