In Light on Yoga, BKS Iyengar wrote: “The ancient books have called Sirsasana the king of all asanas and the reasons are not hard to find. When we are born, normally the head comes out first and then the limbs. The skull encases the the brain, which controls the nervous system and the organs of sense. The brain is the seat of intelligence, knowledge, discrimination, wisdom and power. It is the seat of Brahman, the soul.” (p. 189)
Iyengar recommended the pose “for those with brains that tire easily” because it sent blood flow to the pituitary and pineal glands of the brain needed for “growth, health, and vitality.”(p.190) “Regular and precise practice of Sirsasana develops the body, disciplines the mind and widens the horizons of the spirit. One becomes balanced and self-reliant in pain and pleasure, loss and gain, shame and fame and defeat and victory.” (p. 190)
Yoga Journal lists some of the benefits of headstand as “calms the brain…; stimulates the pituitary and pineal glands; strengthens arms, legs, and spine; strengthens lungs; tones abdominal organs; improves digestion; relieves menopause; and therapeutic for asthma, infertility, insomnia, and sinusitis.”
The website mindbodygreen.com provides 10 Reasons To Do a Headstand Everyday.