Maintained cerebral oxygenation during maximal self-paced exercise in elite Kenyan runners

J. Santos-Concejero, F. Billaut, L. Grobler, J. Oliván, T. D. Noakes, R. Tucker
2015 Journal of applied physiology  
The purpose of this study was to analyze the cerebral oxygenation response to maximal self-paced and incremental exercise in elite Kenyan runners from the Kalenjin tribe. On two separate occasions, 15 elite Kenyan distance runners completed a 5-km time trial (TT) and a peak treadmill speed test (PTS). Changes in cerebral oxygenation were monitored via near-infrared spectroscopy through concentration changes in oxy-and deoxyhemoglobin (⌬[O2Hb] and ⌬[HHb]), tissue oxygenation index (TOI), and
more » ... l hemoglobin index (nTHI). During the 5-km TT (15.2 Ϯ 0.2 min), cerebral oxygenation increased over the first half (increased ⌬[O2Hb] and ⌬[HHb]) and, thereafter, ⌬[O2Hb] remained constant (effect size, ES ϭ 0.33, small effect), whereas ⌬[HHb] increased until the end of the trial (P Ͻ 0.05, ES ϭ 3.13, large effect). In contrast, during the PTS, from the speed corresponding to the second ventilatory threshold, ⌬[O2Hb] decreased (P Ͻ 0.05, ES ϭ 1.51, large effect), whereas ⌬[HHb] continued to increase progressively until exhaustion (P Ͻ 0.05, ES ϭ 1.22, large effect). Last, the TOI was higher during the PTS than during the 5-km TT (P Ͻ 0.001, ES ϭ 3.08; very large effect), whereas nTHI values were lower (P Ͻ 0.001, ES ϭ 2.36, large effect). This study shows that Kenyan runners from the Kalenjin tribe are able to maintain their cerebral oxygenation within a stable range during a self-paced maximal 5-km time trial, but not during an incremental maximal test. This may contribute to their long-distance running success.
doi:10.1152/japplphysiol.00909.2014 pmid:25414248 fatcat:yijaptg2n5gtncdtasvzthtxwe