Greater Performance Impairment of Black Runners than White Runners when Running in Hypoxia

Abstract

This study aimed to compare the response of performance-matched black and white runners during maximal and sub-maximal running in normoxic and hypoxic conditions. 14 well-trained runners (8 black, 6 white) performed 2 incremental maximal exercise tests and 2 fatigue resistance tests at 21% O₂ (normoxia) or 14% O₂ (hypoxia). Respiratory parameters, heart rate (HR), lactate concentration ([La^-]) as well as arterial saturation (SpO₂) were measured. Enzyme activities and myosin heavy chain content (MHC) were also measured. White runners reached a significantly greater peak treadmill speed and a higher HR_max than black runners in hypoxia (p<0.05). Additionally, White runners achieved a greater time to fatigue than black runners (p<0.05), with black runners displaying a greater decline in performance in hypoxia compared to normoxia (20.3% vs. 13.4%, black vs. white, respectively). However, black runners presented lower [La^-] and higher SpO₂ than white runners in hypoxia (p<0.05). Black runners had a higher proportion of MHC IIa and higher lactate dehydrogenase activity (p<0.05). The greater performance impairment observed in black runners in hypoxia suggests a greater performance sensitivity to this condition, despite the maintenance of physiological variables such as SpO₂ and [La ⁻ ] within a smaller range than white runners.

Key words

arterial saturation - time to fatigue - enzyme activity - ethnicity - lactate

• References

• 1 Baker J, Horton S. East African running dominance revisited: a role for stereotype threat?. Br J Sports Med 2003; 37: 553-555
• 2 Bosch AN, Goslin BR, Noakes TD, Dennis SC. Physiological differences between black and white runners during a treadmill marathon. Eur J Appl Physiol 1990; 61: 68-72
• 3 Bright W. International Encyclopaedia of Linguistics. New York: Oxford University Press; 1992
• 4 Calbet JA. Oxygen tension and content in the regulation of limb blood flow. Acta Physiol Scand 2000; 168: 465-472
• 5 Carrillo AE, Koutedakis Y, Flouris AD. Early life mammalian biology and later life physical performance: maximizing physiological adaptation. Br J Sports Med 2011; 45: 1000-1001
• 6 Clerbaux T, Gustin P, Detry B, Cao ML, Frans A. Comparative study of the oxyhaemoglobin dissociation curve of four mammals: man, dog, horse and cattle. Comp Biochem Physiol Comp Physiol 1993; 106: 687-694
• 7 Coetzer P, Noakes TD, Sanders B, Lambert MI, Bosch AN, Wiggins T, Dennis SC. Superior fatigue resistance of elite black South African distance runners. J Appl Physiol 1993; 75: 1822-1827
• 8 Cohen J. Statistical power analysis for the behavioral sciences. Hillsdale, NJ: Editorial Lawrence Erlbaum Associates; 1988
• 9 Donnelly P. Kenyan runners from the Rift Valley (2,000 metres above sea level) have dominated world middle and endurance events for thirty years. J Sci Med Sport 2000; 3: 5-6
• 10 Evans WJ, Phinney SD, Young VR. Suction applied to a muscle biopsy maximizes sample size. Med Sci Sports Exerc 1982; 14: 101-102
• 11 Gladden LB. Lactate metabolism: a new paradigm for the third millennium. J Physiol 2004; 558: 5-30
• 12 Harley YX, Kohn TA, St Clair Gibson A, Noakes TD, Collins M. Skeletal muscle monocarboxylate transporter content is not different between black and white runners. Eur J Appl Physiol 2009; 105: 623-632
• 13 Harms CA, McClaran SR, Nickele GA, Pegelow DF, Nelson WB, Dempsey JA. Effect of exercise-induced arterial O2 desaturation on VO2max in women. Med Sci Sports Exerc 2000; 32: 1101-1108
• 14 Harriss DJ, Atkinson G. Ethical standards in sport and exercise science research: 2014 update. Int J Sports Med 2013; 34: 1025-1028
• 15 Hopkins WG, Marshall SW, Batterham AM, Hanin J. Progressive statistics for studies in sports medicine and exercise science. Med Sci Sports Exerc 2009; 41: 3-13
• 16 Kohn TA, Essén-Gustavsson B, Myburgh KH. Do skeletal muscle phenotypic characteristics of Xhosa and Caucasian endurance runners differ when matched for training and racing distances?. J Appl Physiol 2007; 103: 932-940
• 17 Kohn TA, Myburgh KH. Electrophoretic separation of human skeletal muscle myosin heavy chain isoforms: the importance of reducing agents. J Physiol Sci 2006; 56: 355-360
• 18 Koskolou MD, McKenzie DC. Arterial hypoxemia and performance during intense exercise. Eur J Appl Physiol 1994; 68: 80-86
• 19 Lane AB, Soodyall H, Arndt S, Ratshikhopha ME, Jonker E, Freeman C, Young L, Morar B, Toffie L. Genetic substructure in South African Bantu-speakers: evidence from autosomal DNA and Y-chromosome studies. Am J Phys Anthropol 2002; 119: 175-185
• 20 Larsen HB. Kenyan dominance in distance running. Comp Biochem Physiol Mol Integr Physiol 2003; 136: 161-170
• 21 Lucía A, Esteve-Lanao J, Oliván J, Gómez-Gallego F, San Juan AF, Santiago C, Pérez M, Chamorro-Viña C, Foster C. Physiological characteristics of the best Eritrean runners-exceptional running economy. Appl Physiol Nutr Met 2006; 31: 530-540
• 22 Marino F, Lambert MI, Noakes TD. Superior performance of African runners in warm humid but not in cool environmental conditions. J Appl Physiol 2004; 96: 124-130
• 23 Noakes TD, St Clair Gibson A, Lambert EV. From catastrophe to complexity: a novel model of integrative central neural regulation of effort and fatigue during exercise in humans. Br J Sports Med 2004; 38: 511-514
• 24 Nielsen HB. Arterial desaturation during exercise in man: implication for O2 uptake and work capacity. Scand J Med Sci Sports 2003; 13: 339-358
• 25 Onywera VO, Scott RA, Boit MK, Pitsiladis YP. Demographic characteristics of elite Kenyan endurance runners. J Sports Sci 2006; 24: 415-422
• 26 Powers SK, Dodd S, Lawler J, Landry G, Kirtley M, McKnight T, Grinton S. Incidence of exercise induced hypoxemia in elite endurance athletes at sea level. Eur J Appl Physiol 1988; 58: 298-302
• 27 Rasmussen J, Hanel B, Diamant B, Secher NH. Muscle mass effect on arterial desaturation after maximal exercise. Med Sci Sports Exerc 1991; 23: 1349-1352
• 28 Romer LM, Haverkamp HC, Lovering AT, Pegelow DF, Dempsey JA. Effect of exercise-induced arterial hypoxemia on quadriceps muscle fatigue in healthy humans. Am J Physiol 2006; 290: R365-R375
• 29 Saltin B, Kim CK, Terrados N, Larsen H, Svedenhag J, Rolf CJ. Morphology, enzyme activities and buffer capacity in leg muscles of Kenyan and Scandinavian runners. Scand J Med Sci Sports 1995; 5: 222-230
• 30 Scott RA, Georgiades E, Wilson RH, Goodwin WH, Wolde B, Pitsiladis YP. Demographic characteristics of elite Ethiopian endurance runners. Med Sci Sports Exerc 2003; 35: 1727-1732
• 31 Scott RA, Wilson RH, Goodwin WH, Moran CN, Georgiades E, Wolde B, Pitsiladis YP. Mitochondrial DNA lineages of elite Ethiopian athletes. Comp Biochem Physiol Biochem Mol Bio 2005; 140: 497-503
• 32 Staab JS, Agnew JW, Siconolfi SS. Metabolic and performance responses to uphill and downhill running in distance runners. Med Sci Sports Exerc 2003; 24: 124-127
• 33 Talmadge RJ, Roy RR. Electrophoretic separation of rat skeletal muscle myosin heavy-chain isoforms. J Appl Physiol 1993; 75: 2337-2340
• 34 Tam E, Rossi H, Moia C, Berardelli C, Rosa G, Capelli C, Ferretti G. Energetics of running in top-level marathon runners from Kenya. Eur J Appl Physiol 2012; 112: 3797-3806
• 35 Tucker R, Santos-Concejero J, Collins M. Genetic basis for elite running performance. Br J Sports Med 2013; 47: 545-549
• 36 Weston AR, Karamizrak O, Smith A, Noakes TD, Myburgh KH. African runners exhibit greater fatigue resistance, lower lactate accumulation, and higher oxidative enzyme activity. J Appl Physiol 1999; 86: 915-923
• 37 Weston AR, Mbambo Z, Myburgh KH. Running economy of African and Caucasian distance runners. Med Sci Sports Exerc 2000; 32: 1130-1134
• 38 Wilber RL, Pitsiladis YP. Kenyan and Ethiopian distance runners: what makes them so good?. Int J Sports Physiol Perform 2012; 7: 92-102