Journal of Applied Physiology, Vol 76, Issue 2 610-615, Copyright © 1994 by American Physiological Society

ARTICLES

Beta-adrenergic blockade does not prevent the lactate response to exercise after acclimatization to high altitude

R. S. Mazzeo, G. A. Brooks, G. E. Butterfield, A. Cymerman, A. C. Roberts, M. Selland, E. E. Wolfel and J. T. Reeves
Department of Kinesiology, University of Colorado, Boulder 80309.

We examined the extent to which epinephrine influences blood lactate adjustments to exercise during both acute (AC) and chronic (CH) high-altitude exposure. Eleven male sea level residents were divided into a control group (n = 5) receiving a placebo or a drug group (n = 6) receiving 240 mg/day of propranolol. All subjects were studied at rest and during 45 min of submaximal exercise (approximately 50% of sea level maximal O2 uptake) at sea level (SL) and within 4 h of exposure to and after 3 wk residence at 4,300 m (summit of Pikes Peak). Blood samples were collected from the femoral artery for epinephrine and lactate concentration. Exercising blood lactate concentration was significantly different across all altitude conditions such that AC > CH > SL (P < 0.05). For a given arterial O2 saturation, mean exercising blood lactates were lower for the beta-blocked group compared with controls; however, both groups demonstrated similar patterns across all conditions. Epinephrine levels during exercise followed a similar pattern to that of lactate, averaging 0.67, 0.43, and 0.29 ng/ml for AC, CH, and SL, respectively. The correlation between lactate and epinephrine was 0.93 and 0.84 for control and beta-blocked subjects, respectively. Whereas during exercise epinephrine was consistently higher for the beta-blocked group than controls, this difference was only significant during CH exposure. The epinephrine response was related to the extent of hypoxia in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

This article has been cited by other articles:

				G. van Hall, C. Lundby, M. Araoz, J. A. L. Calbet, M. Sander, and B. Saltin The lactate paradox revisited in lowlanders during acclimatization to 4100 m and in high-altitude natives J. Physiol., March 1, 2009; 587(5): 1117 - 1129. [Abstract] [Full Text] [PDF]

				C. Lundby, R. Boushel, P. Robach, K. Moller, B. Saltin, and J. A. L. Calbet During hypoxic exercise some vasoconstriction is needed to match O2 delivery with O2 demand at the microcirculatory level J. Physiol., January 1, 2008; 586(1): 123 - 130. [Abstract] [Full Text] [PDF]

				G. van Hall COUNTERPOINT: THE LACTATE PARADOX DOES NOT OCCUR DURING EXERCISE AT HIGH ALTITUDE J Appl Physiol, June 1, 2007; 102(6): 2399 - 2401. [Full Text] [PDF]

				R. S. Mazzeo, N. H. Secher, P. Rasmussen, B. Kayser, P. D. Wagner, M. Samaja, M. Guazzi, B. Grassi, M. Marzorati, B. Kayser, et al. Comments on Point:Counterpoint: "The lactate paradox does/does not occur during exercise at high altitude" J Appl Physiol, June 1, 2007; 102(6): 2403 - 2405. [Full Text] [PDF]

				G van Hall, J A L Calbet, H Sondergaard, and B Saltin The re-establishment of the normal blood lactate response to exercise in humans after prolonged acclimatization to altitude J. Physiol., November 1, 2001; 536(3): 963 - 975. [Abstract] [Full Text] [PDF]

				R. S. Mazzeo, J. D. Carroll, Gail. E. Butterfield, B. Braun, P. B. Rock, E. E. Wolfel, S. Zamudio, and L. G. Moore Catecholamine responses to {alpha}-adrenergic blockade during exercise in women acutely exposed to altitude J Appl Physiol, January 1, 2001; 90(1): 121 - 126. [Abstract] [Full Text] [PDF]

				M. L. Parolin, L. L. Spriet, E. Hultman, M. G. Hollidge-Horvat, N. L. Jones, and G. J. F. Heigenhauser Regulation of glycogen phosphorylase and PDH during exercise in human skeletal muscle during hypoxia Am J Physiol Endocrinol Metab, March 1, 2000; 278(3): E522 - E534. [Abstract] [Full Text] [PDF]

				G. A. Brooks, E. E. Wolfel, G. E. Butterfield, A. Cymerman, A. C. Roberts, R. S. Mazzeo, and J. T. Reeves Poor relationship between arterial [lactate] and leg net release during exercise at 4,300 m altitude Am J Physiol Regulatory Integrative Comp Physiol, October 1, 1998; 275(4): R1192 - R1201. [Abstract] [Full Text] [PDF]

				E. E. Wolfel, M. A. Selland, A. Cymerman, G. A. Brooks, G. E. Butterfield, R. S. Mazzeo, R. F. Grover, and J. T. Reeves O2 extraction maintains O2 uptake during submaximal exercise with beta -adrenergic blockade at 4,300 m J Appl Physiol, September 1, 1998; 85(3): 1092 - 1102. [Abstract] [Full Text] [PDF]

				R. S. Richardson, E. A. Noyszewski, J. S. Leigh, and P. D. Wagner Lactate efflux from exercising human skeletal muscle: role of intracellular PO2 J Appl Physiol, August 1, 1998; 85(2): 627 - 634. [Abstract] [Full Text] [PDF]