1. Please introduce yourself to the readers (how you started in the profession, education, credentials, experience, etc.).
My name is Jordan Santos Concejero (29 years old). I studied biology and got my PhD in Exercise Physiology at the University of the Basque Country UPV/EHU (Spain) a few years ago.
My PhD thesis was entitled “Physiological and biomechanical responses to exercise in runners of different ethnic origin, distance specialisation and athletic ability”. I am so interested in athletics and exercise physiology because I was a competitive international runner when I was younger (some of my personal best times: 3’43”46 in 1500m -2007- and 7’59”21 in 3000m indoor in 2011. I even reached the final -7º- in the European U23 championships in 2007 with the Spanish team), so my main goals have always been to know what makes some athletes faster than others.
After earning my PhD, I moved to Cape Town (South Africa) where I spent almost 3 years doing a Postdoc under Timothy Noakes’ supervision (one of the best exercise physiologists in the world). The goal of my Postdoc was to unravel the Kenyan running phenomenon and we are starting to publish our first findings now (on brain oxygenation for example, but there are more publications coming soon on 3D biomechanical variables, ground contact forces, neuromuscular activity etc.)
Currently, I work as a researcher and lecturer at the University of the Basque Country UPV/EHU (Spain). I just came back from South Africa a couple of months ago.
2. You recently published an article on cerebral oxygenation in Kenyan runners. First, what do we know about cerebral oxygenation and fatigue?
Well, many studies have shown that fatigue resulting from maximal exercise in healthy humans is associated with a decline in cerebral oxygenation and that athletes who can maintain their brain oxygenation within an stable range are likely to perform better. This happens because a drop in cerebral oxygenation seems to affect the cerebral cortex activity and muscle recruitment.
3. How is cerebral oxygenation (oxygen brain) measured?
We measured it using a continuous-wave, functional, near-infrared spectrometer (NIRO-200X, Hamamatsu, Japan) which allowed us to monitor changes in cerebral haemoglobin concentrations.
We calculated the changes of tissue oxy-haemoglobin and deoxy-haemoglobin (μmol/cm) using a modified form of the Beer-Lambert law and the tissue oxygenation index and the normalised total hemoglobin index using spatially-resolved spectroscopy (tissue oxygenation index represents the tissue saturation and normalised haemoglobin index is an absolute figure of the total haemoglobin).
4. What did your study look at?
In our study we looked at the cerebral oxygenation changes in elite Kenyan runners (from the Kalenjin tribe to be more specific) during a maximal self-paced exercise (5-km time trial) and a maximal incremental exercise (typical peak treadmill speed test).
5. What were the results of your study?
We found that changes in cerebral oxy-haemoglobin and deoxy-haemoglobin in elite Kalenjin runners are similar to what has been reported in well-trained European runners during maximal incremental exercise to volitional exhaustion. However, the novel finding of our study was that their cerebral oxygenation response differed from that previously observed during self-paced 5-km time trials, and therefore this study offers, another possible physiological mechanism for their unparalled, multifactorial sporting success. That is, we found that Kalenjin runners are able to maintain the oxygenation of their prefrontal lobe through a 5-km time trial within an stable range. This may contribute to the attenuation of the development of central fatigue and a subsequent decline in performance.
6. What were the practical implications for coaches and elite athletes from your study?
Unfortunately… not many. We explain their maintained cerebral oxygenation because of early life factors such as prenatal exposure to high altitude or high physical activity levels during childhood. Nowadays, we don’t know how brain oxygenation can be improved through training. This is something that you are born with (or at least, that is acquired during your early years).
7. Can you explain more about the possible mechanisms for higher cerebral oxygenation in the Kenyan runners?
As I said above, because of the influence of early-life factors, such as prenatal exposure to high altitude and high physical activity levels during childhood. Prenatal exposure to high altitude triggers cerebral vasodilator responses at muscle and endothelium level by stimulating extensive cerebrovascular remodeling that increases wall thickness but decreases overall contractility. With regards to the high physical activity levels during childhood, they may cause, among other adaptations, the stimulation of trophic factors and neuronal growth as well as augmented cerebral circulation through increased vascularisation of the brain.
Another potential explanation is that Kenyan runners may have an attenuated reduction in PaCO2, which would delay the cerebral vasoconstriction that has been demonstrated at high intensities. In fact, African runners display an increased oxidative enzyme activity and a subsequent lower lactate production. The consequences of this more efficient aerobic metabolism would be that Kenyan runners are able to exercise at higher intensities, relying more on aerobic sources of energy and producing less CO2 through the bicarbonate breakdown to compensate for acidosis. This would ultimately attenuate hyperventilation, hypocapnia and, finally, vasoconstriction
8. In swimming, there are brief periods of hypoxia. Do you think more frequent breathing would help prevent central fatigue?
I would say that in swimming (at least when swimming long distances), the more you breathe the better as long as this more frequent breathing does not slow you down (because of the impairment in the biomechanical efficiency) [something Bruce Gemmell and I spoke about in the Swimming Science Podcast].
9. What are some other contributors to central fatigue?
Maybe the most important one is motivation. Psychology plays a huge role; even if for a pure physiologist like me is hard to admit.
10. Who is doing the most interesting research currently in your field? What are they doing?
The group lead by Samuele Marcora. They are trying to understand how our mind can regulate performance. They have even proposed a new fatigue model called the psychobiological model.
11. What makes your research different from others?
That for the first time we have studied how their brain works. Everybody has tried to find the Kenyan secret in their legs and we, for the first time, have looked at their brains.
12. Which teachers have most influenced your research?
Prof Timothy Noakes and Dr Ross Tucker were my mentors in South Africa and some of the most intelligent people I have ever known. Apart from them, Dr Jon Irazusta (world leader in physiology) taught how to be a good scientist and I still learn from him every day.
13. What research or projects are you currently working on or should we look from you in the future?
How to improve running economy is something that I find particularly interesting (for example, we have an article under review on how barefoot running can help). However, for at least the following 1-2 years I plan to keep analysing the data I collected during my Postdoc in South Africa and I will try to add new possible explanations for the multifactorial Kenyan phenomenon.
The post Effects of Oxygen Levels on the Brain appeared first on Swimming Science.