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Int J Sports Med. 2014 Sep;35(10):809-16. doi: 10.1055/s-0034-1367012. Epub 2014 Feb 27.

Greater performance impairment of black runners than white runners when running in hypoxia.

Author information

1
UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, South Africa.
2
Stellenbosch University, Department of Physiological Sciences, Stellenbosch, South Africa.
3
Swedish University of Agricultural Sciences, Department of Large Animal Clinical Sciences, Uppsala, Sweden.

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 HRmax 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.

PMID:
24577858
DOI:
10.1055/s-0034-1367012
[Indexed for MEDLINE]

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