Neuroadrenergic abnormalities, including a predominant activity of parasympathetic nerve and blunted hormone secretion, are recognized in the overweight patients. This study aimed to examine whether the "Senobi" breathing method, a stretch-breathing exercise that we have developed, could activate or recover sympathetic nervous system activity that leads to the loss of body weight. Forty pre-menopausal women, aged 40 to 50 years, participated in this study. Twenty were healthy and the other 20 were overweight (body mass index>25 and body fat>30%). Sympathetic nerve activity was assessed using equipment that analyzes cardiac-beat variation, and several urinary hormone levels were examined before and 30 min after performing the "Senobi" breathing exercise. The average proportion of sympathetic nerve among healthy women during daytime hours (10:00 AM to 12:00 PM) was 62.6%±2.6%. On the other hand, that of overweight women was 33.5%±0.4%. After 1 min of the "Senobi" breathing, substantial up-regulation of sympathetic nerve activity and increased urinary hormone secretion were observed in the overweight women but not in the healthy controls. Moreover, after repeating the exercise for a month, the obese patients showed significant loss of body fat. The "Senobi" breathing exercise was found to be effective for weight loss in obesity possibly by regulating the autonomic nervous system and the hormone secretion.