To study whether controlled breathing, known to ameliorate motion sickness, speeds habituation to nauseogenic motion when used in a novel accelerated training regime, 30 participants (13 men, 17 women, ages 18-51 years) were randomized to either a Breathing group or a Control group. Randomization was balanced for rotation tolerance measured during a first exposure to off-vertical axis rotation (OVAR 72Â°sec.-1). Participants subsequently received four exposures to OVAR in 1-hr. (accelerated training). The Breathing group followed taped instructions to control their breathing during training and when retested the next day. There was overall habituation with stimulus repetition, shown by an increase in tolerance for motion, a reduction in symptoms, and speeded recovery times on retesting. There was a tendency for greater habituation with controlled breathing.