Christine lamberto – academia.edu anoxic brain injury

Eight men performed three series of 5-min exercise on a cycle ergometer at 65% of normoxic maxima… More eight men performed three series of 5-min exercise on a cycle ergometer at 65% of normoxic maximal O 2 consumption in four conditions: (1) voluntary hypo-ventilation (VH) in normoxia (VH 0.21), (2) VH in hyper-oxia (inducing hypercapnia) (inspired oxygen fraction [F I O 2 ] = 0.29; VH 0.29), (3) normal breathing (NB) in hypoxia (F I O 2 = 0.157; NB 0.157), (4) NB in normoxia (NB 0.21). Using near-infrared spectroscopy, changes in concentration of oxy-(D[O 2 hb]) and deoxyhemoglobin (D[hhb]) were measured in the vastus lateralis muscle.


D[O 2 hb -hhb] and D[O 2 hb ? HHb] were calculated and used as oxygenation index and change in regional blood volume, respectively.Anoxic brain injury earlobe blood samples were taken throughout the exercise. Both VH 0.21 and NB 0.157 induced a severe and similar hypoxemia (arterial oxygen saturation [sao 2 ] \ 88%) whereas sao 2 remained above 94% and was not different between VH 0.29 and NB 0.21 . Arterialized O 2 and CO 2 pressures as well as P50 were higher and ph l…

This study aimed to determine the cardiovascular responses during a prolonged exercise with volun… More this study aimed to determine the cardiovascular responses during a prolonged exercise with voluntary hypoventilation (VH). 7 men performed 3 series of 5-min exercise at 65% of normoxic maximal O (2) uptake under 3 conditions: (1) normal breathing (NB) in normoxia (NB (0.21)), (2) VH in normoxia (VH (0.21)), (3) NB in hypoxia (NB (0.157), inspired oxygen fraction=0.157).Anoxic brain injury in both VH (0.21) and NB (0.157), there was a similar drop in arterial oxygen saturation and arterial O (2) content (cao (2)) which were lower than in NB (0.21). Heart rate (HR), stroke volume, and cardiac output (-) were higher in VH (0.21) than in NB (0.21) during most parts of exercise whereas there was no difference between NB (0.157) and VH (0.21) or NB (0.21). HR variability analysis suggested an increased sympathetic modulation in VH (0.21) only. O (2) transport and oxygen uptake were generally not different between interventions. Mixed venous O (2) content (C-O (2)) was lower in NB (0.157) than in both VH (0…

We aimed to evaluate 1) the altitude where maximal heart rate (HR (max)) decreases significantly …Anoxic brain injury more we aimed to evaluate 1) the altitude where maximal heart rate (HR (max)) decreases significantly in both trained and untrained subjects in moderate acute hypoxia, and 2) if the HR (max) decrease could partly explain the drop of V.O (2max). Seventeen healthy males, nine trained endurance athletes (TS) and eight untrained individuals (US) were studied. Subjects performed incremental exercise tests at sea level and at 5 simulated altitudes (1000, 1500, 2500, 3500, 4500 meters). Power output (PO), heart rate (HR), arterial oxygen saturation (sao (2)), oxygen uptake (V.O (2)), arterialized blood ph and lactate were measured. Both groups showed a progressive reduction in V.O (2max). The decrement in HR (max) (deltahr (max)) was significant from 1000 m for TS and 2500 m for US and more important in TS than US (at 1500 m and 3500 m).Anoxic brain injury at maximal exercise, TS had a greater reduction in sao (2) (deltasao (2)) at each altitude. DeltaHR (max) observed in TS was correlated with deltasao (2). When…

Eight men performed three series of 5-min exercise on a cycle ergometer at 65% of normoxic maxima… More eight men performed three series of 5-min exercise on a cycle ergometer at 65% of normoxic maximal O 2 consumption in four conditions: (1) voluntary hypo-ventilation (VH) in normoxia (VH 0.21), (2) VH in hyper-oxia (inducing hypercapnia) (inspired oxygen fraction [F I O 2 ] = 0.29; VH 0.29), (3) normal breathing (NB) in hypoxia (F I O 2 = 0.157; NB 0.157), (4) NB in normoxia (NB 0.21). Using near-infrared spectroscopy, changes in concentration of oxy-(D[O 2 hb]) and deoxyhemoglobin (D[hhb]) were measured in the vastus lateralis muscle.Anoxic brain injury D[O 2 hb -hhb] and D[O 2 hb ? HHb] were calculated and used as oxygenation index and change in regional blood volume, respectively. Earlobe blood samples were taken throughout the exercise. Both VH 0.21 and NB 0.157 induced a severe and similar hypoxemia (arterial oxygen saturation [sao 2 ] \ 88%) whereas sao 2 remained above 94% and was not different between VH 0.29 and NB 0.21 . Arterialized O 2 and CO 2 pressures as well as P50 were higher and ph l…

This study aimed to determine the cardiovascular responses during a prolonged exercise with volun… More this study aimed to determine the cardiovascular responses during a prolonged exercise with voluntary hypoventilation (VH). 7 men performed 3 series of 5-min exercise at 65% of normoxic maximal O (2) uptake under 3 conditions: (1) normal breathing (NB) in normoxia (NB (0.21)), (2) VH in normoxia (VH (0.21)), (3) NB in hypoxia (NB (0.157), inspired oxygen fraction=0.157).Anoxic brain injury in both VH (0.21) and NB (0.157), there was a similar drop in arterial oxygen saturation and arterial O (2) content (cao (2)) which were lower than in NB (0.21). Heart rate (HR), stroke volume, and cardiac output (-) were higher in VH (0.21) than in NB (0.21) during most parts of exercise whereas there was no difference between NB (0.157) and VH (0.21) or NB (0.21). HR variability analysis suggested an increased sympathetic modulation in VH (0.21) only. O (2) transport and oxygen uptake were generally not different between interventions. Mixed venous O (2) content (C-O (2)) was lower in NB (0.157) than in both VH (0…

We aimed to evaluate 1) the altitude where maximal heart rate (HR (max)) decreases significantly …Anoxic brain injury more we aimed to evaluate 1) the altitude where maximal heart rate (HR (max)) decreases significantly in both trained and untrained subjects in moderate acute hypoxia, and 2) if the HR (max) decrease could partly explain the drop of V.O (2max). Seventeen healthy males, nine trained endurance athletes (TS) and eight untrained individuals (US) were studied. Subjects performed incremental exercise tests at sea level and at 5 simulated altitudes (1000, 1500, 2500, 3500, 4500 meters). Power output (PO), heart rate (HR), arterial oxygen saturation (sao (2)), oxygen uptake (V.O (2)), arterialized blood ph and lactate were measured. Both groups showed a progressive reduction in V.O (2max). The decrement in HR (max) (deltahr (max)) was significant from 1000 m for TS and 2500 m for US and more important in TS than US (at 1500 m and 3500 m).Anoxic brain injury at maximal exercise, TS had a greater reduction in sao (2) (deltasao (2)) at each altitude. DeltaHR (max) observed in TS was correlated with deltasao (2). When…