Acute exposure to 4,300 m increased exercise lactate appearance rate to 18.6 mg/kg/min compared to 3.24 at sea level, which decreased to 9.2 mg/kg/min after 3 weeks of acclimatization.
Does acute exposure and acclimatization to high altitude alter blood lactate flux during rest and exercise in healthy men?
The increased arterial lactate concentration during exercise upon acute high-altitude exposure and its subsequent decrease with acclimatization are driven by changes in blood lactate appearance rate.
Absolute Event Rate: 18.6% vs 3.24%
We hypothesized that the increased exercise arterial lactate concentration on arrival at high altitude and the subsequent decrease with acclimatization were caused by changes in blood lactate flux. Seven healthy men age 23 +/- 2 (SE) yr, wt 72.2 +/- 1.6 kg on a controlled diet were studied in the postabsorptive condition at sea level, on acute exposure to 4,300 m, and after 3 wk of acclimatization to 4,300 m. Subjects received a primed-continuous infusion of 6,6-2Dglucose (Brooks et al. J. Appl. Physiol. 70:919-927, 1991) and 3-13Clactate and rested for a minimum of 90 min followed immediately by 45 min of exercise at 101 +/- 3 W, which elicited 51.1 +/- 1% of the sea level peak O2 consumption (VO2peak; 65 +/- 2% of both acute altitude and acclimatization). During rest at sea level, lactate appearance rate (Ra) was 0.52 +/- 0.03 mg.kg-1.min-1; this increased sixfold during exercise to 3.24 +/- 0.19 mg.kg-1.min-1. On acute exposure, resting lactate Ra rose from sea level values to 2.2 +/- 0.2 mg.kg-1.min-1. During exercise on acute exposure, lactate Ra rose to 18.6 +/- 2.9 mg.kg-1.min-1. Resting lactate Ra after acclimatization (1.77 +/- 0.25 mg.kg-1.min-1) was intermediate between sea level and acute exposure values. During exercise after acclimatization, lactate Ra (9.2 +/- 0.7 mg.kg-1.min-1) rose from resting values but was intermediate between sea level and acute exposure values. The increased exercise arterial lactate concentration response on arrival at high altitude and subsequent decrease with acclimatization are due to changes in blood lactate appearance.(ABSTRACT TRUNCATED AT 250 WORDS)
Brooks et al. (Mon,) conducted a other in Healthy (n=7). Acute exposure and acclimatization to 4,300 m altitude vs. Sea level was evaluated on Lactate appearance rate (Ra) during exercise. Acute exposure to 4,300 m increased exercise lactate appearance rate to 18.6 mg/kg/min compared to 3.24 at sea level, which decreased to 9.2 mg/kg/min after 3 weeks of acclimatization.