Reduced hypoxic ventilatory response with preserved blood oxygenation in yoga trainees and Himalayan Buddhist monks at altitude: evidence of a different adaptive strategy?

Yoga induces long-term changes in respiratory function and control. We tested whether it represents a successful strategy for high-altitude adaptation. We compared ventilatory, cardiovascular and hematological parameters in: 12 Caucasian yoga trainees and 12 control sea-level residents, at baseline and after 2-week exposure to high altitude (Pyramid Laboratory, Nepal, 5,050 m), 38 active lifestyle high-altitude natives (Sherpas) and 13 contemplative lifestyle high-altitude natives with practice of yoga-like respiratory exercises (Buddhist monks) studied at 5,050 m. At baseline, hypoxic ventilatory response (HVR), red blood cell count and hematocrit were lower in Caucasian yoga trainees than in controls. After 14 days at altitude, yoga trainees showed similar oxygen saturation, blood pressure, RR interval compared to controls, but lower HVR (-0.44 +/- 0.08 vs. -0.98 +/- 0.21 l/min/m/%SaO(2), P < 0.05), minute ventilation (8.3 +/- 0.9 vs. 10.8 +/- 1.6 l/min, P < 0.05), breathing rate (indicating higher ventilatory efficiency), and lower red blood cell count, hemoglobin, hematocrit, albumin, erythropoietin and soluble transferrin receptors. Hypoxic ventilatory response in monks was lower than in Sherpas (-0.23 +/- 0.05 vs. -0.63 +/- 0.09 l/min/m/%SaO(2), P < 0.05); values were similar to baseline data of yoga trainees and Caucasian controls, respectively. Red blood cell count and hematocrit were lower in monks as compared to Sherpas. In conclusion, Caucasian subjects practicing yoga maintain a satisfactory oxygen transport at high altitude, with minimal increase in ventilation and with reduced hematological changes, resembling Himalayan natives. Respiratory adaptations induced by the practice of yoga may represent an efficient strategy to cope with altitude-induced hypoxia.

Vasovagal syncope in emergency room patients: analysis of a metropolitan area registry.

The aim of this study was to assess the epidemiology of syncope in unselected patients referred to an emergency room and eventually admitted to the clinical wards to perform a complete work-up, and to analyze the costs of hospitalization. The clinical charts of all patients referred for all causes to the emergency rooms of three hospitals in the Florence area during the year 2000 and of all patients admitted from the emergency rooms to the clinical wards with a diagnosis of lone-related (vasovagal) or disease-related syncope were revised. A total of 1,290 (3.36%) cases of syncope out of 38,330 presentations were registered; among these, 702 cases (1.83% of all presentations, 54% of all syncopes) were directly discharged, and 443 cases (1.14% of all presentations, 34% of all syncopes) were hospitalized. The remaining 149 cases (12% of all syncopes) refused admission. Following admission, 500 patients were discharged with the diagnosis of syncope: 115 lone-related (23%) and 385 disease-related syncopes (77%). A cost-benefit analysis of the hospitalized patients showed that admitting patients with lone syncope leads to an economical loss to the hospital.