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

Area of Science:

• Exercise Physiology
• Neuroscience
• Sports Science

Background:

• Elite Kenyan runners, particularly from the Kalenjin tribe, exhibit exceptional endurance.
• Understanding the physiological adaptations underlying their performance is crucial for sports science.
• Cerebral oxygenation plays a vital role in cognitive function and sustained physical exertion.

Purpose of the Study:

• To investigate the cerebral oxygenation response in elite Kenyan runners during maximal self-paced and incremental exercise.
• To compare brain oxygenation dynamics between a 5-km time trial and a peak treadmill speed test.

Main Methods:

• Near-infrared spectroscopy (NIRS) was used to monitor cerebral oxygenation.
• Measurements included changes in oxy- and deoxyhemoglobin (Δ[O2Hb], Δ[HHb]), tissue oxygenation index (TOI), and total hemoglobin index (nTHI).
• Fifteen elite Kenyan distance runners completed both a 5-km time trial and a peak treadmill speed test.

Main Results:

• During the 5-km time trial, Δ[O2Hb] remained stable after the initial phase, while Δ[HHb] increased.
• During the peak treadmill speed test, Δ[O2Hb] decreased significantly, and Δ[HHb] increased progressively.
• Tissue oxygenation index (TOI) was higher during the peak treadmill speed test compared to the 5-km time trial.

Conclusions:

• Elite Kenyan runners maintain cerebral oxygenation during self-paced maximal exercise but experience a decrease during incremental maximal exercise.
• These distinct cerebral oxygenation responses may be a contributing factor to their remarkable long-distance running capabilities.
• Further research could explore the neural mechanisms behind these observed differences.