We in the West have not yet properly grasped the power of Yoga practices to influence a person's health, mental state, and destiny. If a person suffers from too much heat, obviously fire would increase heat and cause more suffering. If they are too stimulated, stimulation will be harmful etc. In the case of too much heat, heating asanas, meditations, and pranayams will cause even more troubles than fire because their power to generate inner heat is greater. For the very unfortunate teachers who advise people to do spiritual practices which increase their imbalance, this creates very bad karma. I have seen many people with constant pain; mental distress; inability to take food without severe pain; inability to sleep at night; and suffering from various dis-ease conditions on account of their yoga practices. These imbalances start out in a very subtle way but eventually become crippling when people do the wrong practice for their constitution for an extended time. It is remarkable how much damage people do themselves by practicing Yoga in this way. The results of a person's practice return immediately and they affect every aspect of a person's life in time. If they do the wrong practices, people become incapable of fulfilling their dharma, incapable of working, and incapable of enjoying life. Many of the unfortunate students who suffer from the practices they do, have such great faith in their teachers, that they do not even want to consider that their practice is the source of their suffering. They have been misled into thinking that doing the wrong practices in the wrong ways will benefit them, and they hold firmly to this belief like religious fanatics.
Wisdom will come for them in time when the suffering has been enough to help them to gain greater discrimination, wisdom and clarity. I have seen many in this state then start teaching, though their own practice has only increased their pain. For the teachers who encourage this sort of practice, it is said that the suffering will be three times greater when it returns to them, because the Yoga practices they teach work on the physical, astral, and causal level. The fruit of this karma may not return immediately, but it will return eventually - because what energy is put out into the world eventually returns to its sender. Perhaps these teachers will be born without limbs, into slavery, or imprisonment in the next lifetime.
It is a great responsibility to teach Yoga which we in the West have not yet learned to take seriously. Teachers are certified after a mere 200 hours of training and they are not tested for knowledge of the subject or for the implementation of the practices to overcome their own shortcomings. It requires great knowledge of the nature of karma and dharma, of energy, of the human body, the mind and the soul to teach Yoga. It is not possible to lead people to realizations we ourselves are yet seeking. To try to do so can bring severe pain and suffering onto oneself. Instead we must strive humbly in our own practice and teach from our experience, however limited it may be. Or it is necessary to only teach those practices which are very gentle and universally balancing. The practices for realization are intense and the same practice that is helpful for one person to gain realization will lead another to the asylum or cemetery. Such practices should only ever be attempted with the guidance and blessing of a qualified teacher. Before certain Yoga practices are even attempted, certain requisite qualities must be there in the student because, without great dispassion, selflessness, faith, courage, patience, discipline, and dedication, the practices of hatha Yoga can cause much harm.
Wise Yoga teachers train and test their students for such qualities over time before they will teach them even the simplest practices of Yoga. This is the traditional way which is still practiced in India. In this way, the knowledge of Yoga is transferred from master to student. And only when the student gains mastery over his or her own mind and body (and mastery over nature) is he or she given the blessing by the Guru to teach others. Those who cannot play a musical instrument do not teach others to play. But in the West we have many who are still learning to meditate teaching others to meditate. Jesus warned about this saying something like "when the blind lead the blind, they will both fall into a pit." This trend will cause great suffering but, in time, wisdom will grow and people will begin to gain faith in the power of Yoga. Sometimes people learn best through their mistakes. So few have the wisdom to listen to the traditional wisdom of the Sages and Saints. So many want to buy a quick and easy path to liberation. There are many opportunities for the unscrupulous to make a few dollars. We must learn we cannot dominate nature. We must develop wisdom and discrimination. Then we will come into harmony with nature.
There are no quick or easy paths to enlightenment. Students must be extremely cautious of teachers and practices which offer or seem to bestow instantaneous results. There is no practice which gives instant awakening, realization, awareness, or enlightenment. There are no quick practices for inner attainments, which can only come after many months or years of dedicated practice. They say if things seem too good to be true, they are. But people have very little patience today to go through the traditional preparations for spiritual practice and they have little time for practice. It is natural that they seek instant results, but just because a practice seems to do something does not mean that it is benefiting a person. Many practices now are designed so people will feel something. They hurt the body and mind, but it is noticeable. It is alarmingly common for the students of certain types of Yoga to experience long-lasting injuries. It is becoming commonplace for Yoga teachers to say and for people to believe that if they do not feel some pain that they are not getting any results from practice. Yoga practice should not hurt. It is not and cannot replace physical exercise. It is not a competition or a performance, though it is often practiced this way now.
Yoga is a silent, inner science of self-discovery. It works when people are prepared to face what is within and when they practice with discipline and dedication under the guidance of a qualified teacher. It is not popular for people to criticize the spiritual practices of others in this world of new-age philosophy and universalism. But, for their own happiness and safety, people must understand that the ways Yoga are being taught and practiced are not traditional and they are very dangerous. Only when people's patience to learn the traditional practices of Yoga has increased will they be able to embark upon the vast study of this great subject which has the power to reveal the ultimate Truth sought by every person on Earth; the nature of the eternal soul.