BLOOD OXYGEN SATURATION AND HEART RATE DURING EXERCISE A MONTH AFTER A HIGH-ALTITUDE ALPINIST EXPEDITION

Some alterations, reached during acclimatization on a high-altitude alpinist expedition, return towards pre-altitude levels at different rates during the deacclimatization phase after returning to normoxia. The aim of the study was to ascertain whether three specific adaptation characteristics-alterations in body weight (BW), arterial blood oxygen saturation (SaO(2)) and heart rate (HR), showed that deacclimatization was completed a month after having reached the summit of Gasherbrum II. Four experienced alpinists (age 45 +/- 8 years, BW 75 +/- 5 kg and body height 171 +/- 9 cm) were tested in the conditions of normoxia and normobaric hypoxia prior to and following a month of deacclimatization after a high-altitude climbing expedition. The results showed that BW was still decreased by about 8 kg (p<.05) a month after reaching the summit. Data obtained during exercise with similar absolute intensity of 202 +/- 28 W showed that SaO(2) rose from 89 +/- 1 to 91 +/- 1% (p<.05) during testing in conditions of hypoxia after the high-altitude expedition. When the data were analysed at the same relative intensity of 2.7 +/- .2 W/kg, the SaO(2) showed an even higher increase to 92 +/- 1% during testing in conditions of hypoxia (p<.05). HR remained similar during testing at a similar absolute intensity in conditions of normoxia (153 +/- 19 min(-1) pre- vs 154 +/- 15 min(-1) post-expedition) and hypoxia (155 +/- 21 min(-1) pre- vs 158 +/- 20 min(-1) post-expedition), however, at the reduced BW during post-expedition testing. HR decreased significantly (p<.05) during similar relative intensity in conditions of hypoxia (155 +/- 21 min(-1) pre- vs 145 +/- 19 post-expedition). HR decreased systematically in all subjects in spite of the fact that it was not significantly different during testing in normoxic conditions. The results showed that deacclimatization, which was observed during submaximal intensity exercise in normoxic conditions and hypoxia, was not completed even a month after the high-altitude alpinist expedition.