Cortisol, testosterone, dehydroepiandrosterone (DHEA), and aldosterone were measured in the blood serum of healthy subjects who adopted the cobra posture (bhujangasana), a key posture of hatha yoga. The subjects were trained in yoga; blood samples were taken before and after the exercise at an interval of no more than 5 min. As revealed with a new confidence interval–evaluating method developed by A.I. Ivanov, cortisol decreased by 11% with a reliability of 0.99 in all subjects, while testosterone increased by 16% with a reliability of 0.95. Changes in DHEA and aldosterone varied. Proceeding from ideas about motor–visceral interactions, the authors hypothesize that, when the subjects adopted the cobra posture, the production of steroid hormones was controlled by neural mechanisms.