TY - JOUR
T1 - Bicarbonate attenuates arterial desaturation during maximal exercise in humans.
AU - Nielsen, Henning B
AU - Bredmose, Per P
AU - Strømstad, Morten
AU - Volianitis, Stefanos
AU - Quistorff, Bjørn
AU - Secher, Niels H
N1 - Keywords: Acidosis; Adult; Carbon Dioxide; Exertion; Heart Rate; Humans; Hydrogen-Ion Concentration; Lactic Acid; Male; Muscle, Skeletal; Oxygen; Pulmonary Gas Exchange; Respiration; Sodium Bicarbonate; Spectroscopy, Near-Infrared
PY - 2002
Y1 - 2002
N2 - The contribution of pH to exercise-induced arterial O2 desaturation was evaluated by intravenous infusion of sodium bicarbonate (Bic, 1 M; 200-350 ml) or an equal volume of saline (Sal; 1 M) at a constant infusion rate during a "2,000-m" maximal ergometer row in five male oarsmen. Blood-gas variables were corrected to the increase in blood temperature from 36.5 +/- 0.3 to 38.9 +/- 0.1 degrees C (P < 0.05; means +/- SE), which was established in a pilot study. During Sal exercise, pH decreased from 7.42 +/- 0.01 at rest to 7.07 +/- 0.02 but only to 7.34 +/- 0.02 (P < 0.05) during the Bic trial. Arterial PO2 was reduced from 103.1 +/- 0.7 to 88.2 +/- 1.3 Torr during exercise with Sal, and this reduction was not significantly affected by Bic. Arterial O2 saturation was 97.5 +/- 0.2% at rest and decreased to 89.0 +/- 0.7% during Sal exercise but only to 94.1 +/- 1% with Bic (P < 0.05). Arterial PCO2 was not significantly changed from resting values in the last minute of Sal exercise, but in the Bic trial it increased from 40.5 +/- 0.5 to 45.9 +/- 2.0 Torr (P < 0.05). Pulmonary ventilation was lowered during exercise with Bic (155 +/- 14 vs. 142 +/- 13 l/min; P < 0.05), but the exercise-induced increase in the difference between the end-tidal O2 pressure and arterial PO2 was similar in the two trials. Also, pulmonary O2 uptake and changes in muscle oxygenation as determined by near-infrared spectrophotometry during exercise were similar. The enlarged blood-buffering capacity after infusion of Bic attenuated acidosis and in turn arterial desaturation during maximal exercise.
AB - The contribution of pH to exercise-induced arterial O2 desaturation was evaluated by intravenous infusion of sodium bicarbonate (Bic, 1 M; 200-350 ml) or an equal volume of saline (Sal; 1 M) at a constant infusion rate during a "2,000-m" maximal ergometer row in five male oarsmen. Blood-gas variables were corrected to the increase in blood temperature from 36.5 +/- 0.3 to 38.9 +/- 0.1 degrees C (P < 0.05; means +/- SE), which was established in a pilot study. During Sal exercise, pH decreased from 7.42 +/- 0.01 at rest to 7.07 +/- 0.02 but only to 7.34 +/- 0.02 (P < 0.05) during the Bic trial. Arterial PO2 was reduced from 103.1 +/- 0.7 to 88.2 +/- 1.3 Torr during exercise with Sal, and this reduction was not significantly affected by Bic. Arterial O2 saturation was 97.5 +/- 0.2% at rest and decreased to 89.0 +/- 0.7% during Sal exercise but only to 94.1 +/- 1% with Bic (P < 0.05). Arterial PCO2 was not significantly changed from resting values in the last minute of Sal exercise, but in the Bic trial it increased from 40.5 +/- 0.5 to 45.9 +/- 2.0 Torr (P < 0.05). Pulmonary ventilation was lowered during exercise with Bic (155 +/- 14 vs. 142 +/- 13 l/min; P < 0.05), but the exercise-induced increase in the difference between the end-tidal O2 pressure and arterial PO2 was similar in the two trials. Also, pulmonary O2 uptake and changes in muscle oxygenation as determined by near-infrared spectrophotometry during exercise were similar. The enlarged blood-buffering capacity after infusion of Bic attenuated acidosis and in turn arterial desaturation during maximal exercise.
U2 - 10.1152/japplphysiol.00398.2000
DO - 10.1152/japplphysiol.00398.2000
M3 - Journal article
C2 - 12133884
SN - 8750-7587
VL - 93
SP - 724
EP - 731
JO - Journal of Applied Physiology
JF - Journal of Applied Physiology
IS - 2
ER -