How elite Kenyan athletes succeed in marathons found

London: Elite Kenyan athletes have greater brain oxygenation during periods of maximum physical effort, which contributes to their success in long-distance races, a new pioneering study has found.

Researchers analysed the response of cerebral oxygenation at maximum and progressive rhythms among elite Kenyan runners from the Kalenjin tribe. A sample of 15 elite Kenyan runners was selected, each with achievements in the Half Marathon of between 1.01 and 1.03.

The cerebral oxygenation was studied during the exercise (basically changes in oxyhaemoglobin, deoxyhaemoglobin, blood flow, arterial saturation, and so on) using NiRS (Near-infrared Spectroscopy) and oximetry readings during a maximum trial of 5 kilometres and a maximum incremental test.

"We can see that the Kenyans were capable of maintaining their oxygenation in a stable manner during the 5 kilometre trial, with implications for the athletes' performance," said Jordan Santos-Concejero from the University of the Basque Country, Spain.

It has been observed that, when cerebral oxygenation in the prefrontal lobule falls, the neural activity in this zone also drops. This zone is closely linked to the control of movement and to decision-making, and it has thus been put forward that this reduction in neuronal activity may explain the drop in performance observed amongst European athletes, on cerebral oxygenation reducing.

Given that, with the Kenyan athletes, this reduction does not occur, "we believe that the neuronal activation in the prefrontal lobule is not compromised and perhaps this capacity of maintaining their cerebral oxygenation in a stable way may contribute to their great performance in long-distance trials," said Santos-Concejero.

The research also focused on the possible causes of this particularity of African athletes, attributing their stable cerebral oxygenation during maximum effort to early lifestyle factors such as the prenatal exposure to high altitudes and the high levels of physical activity during childhood.

"The prenatal exposure to high altitudes has protector effects on the foetus, greater blood flow to the uterine artery, which may involve greater cardiopulmonary capacity in adulthood and, consequently, less incidence of arterial desaturation during high-intensity exercises," researchers said.

Also, the undertaking of physical exercise regularly during childhood implies benefits such as increase in ventricular mass and motor coordination, lower levels of cytokines and, most importantly, greater neural growth as a consequence of the greater vascularisation of the encephalus.

"This last point may partially explain why their cerebral oxygenation is maintained during periods of maximum effort," said Santos-Concejero.

The study was published in the Journal of Applied Physiology.