Why should not asanas be practiced outdoors?

While practicing asanas the body becomes extra-sensitive and attuned to subtle inner currents. The body may catch a cold if it is exposed to sudden changes in temperature due to wind, cold weather, or even contact with cold ground. If it is too hot, the body may overheat, which may be worse for a yogin than catching a cold.

Furthermore, asanas help activate and maintain the ethereal and astral (luminous) layers of our body. After a practice of asanas, our aura, weakened and scattered during the normal activities of the day, becomes more organized and healthy. Additionally, pores open throughout both the physical and subtle bodies, which helps rejuvenate our aura. Yet, during this period, all layers of the human body, particularly the subtle ones, are very sensitive and vulnerable to external influence. If we do asanas outdoors, the energetic fields of trees, grass and even earth will interfere with the subtle systems of our body. If the foreign field is pure and harmonious to ours, this may have a positive effect. Yet, as we cannot be sure (due to our underdeveloped intuition), it is safer to do asanas indoors.

If you have gained sufficient knowledge of your body and asanas through experience, you may make an exception and experiment with asana practice outdoors, if the weather is warm. Generally, however, such experimentation is adventurous and, thus, risky and ill advised.

—Anatole & Shantatma