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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.

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


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.

[Indexed for MEDLINE]

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