The secret of Kenyan success: it’s not the hemoglobin



- Alex Hutchinson (@sweatscience)


April’s issue of Medicine & Science in Sports & Exercise brings another in the long line of studies trying to figure out why Kenyan runners are so much better than the rest of the world (other than some of their East African neighbours). As researchers from the universities of Bayreuth and Tubingen in Germany write:

Possible reasons for this performance superiority range from the physiological to the biomechanical, social, and economic, but none of them appears to be exclusively responsible.

Earlier studies have found that elite Kenyan runners have better running economy than elite Caucasian runners — in other words, they require less oxygen to run at a given level of effort. One theory is that Kenyan muscles somehow use oxygen more efficiently, but studies of muscle morphology and function haven’t been able to pick up any significant differences. Another possibility is that, thanks to adaptations from having ancestors living at altitude for 100,000 years, Kenyans are able to transport more oxygen in their blood to fuel the muscles.

To investigate this possibility, the new study measures total hemoglobin mass (tHb-mass) and blood volume (BV), the two factors that predominantly determine oxygen transport. They compared 10 Kenyans with an average 10K time of 28:29 who were staying in Germany for six weeks with a group of 11 German runners with average 10K time of 30:39. Cutting straight to the chase: when the Kenyans arrived in Germany from altitude, their total hemoglobin mass and blood volume per kilogram of body weight were essentially identical to the Germans. As the six weeks in Germany progressed, the Kenyans got fatter (added 3 kg of bodyweight, including 1 kg of fat), and their hemoglobin and blood measures got worse. The conclusion:

The oxygen transport of the blood, that is, tHb-mass and BV, cannot explain the superior endurance performance of Kenyan runners. All of these parameters are in the same range when compared with those of elite German runners, and tHb-mass even deteriorated after adaptation to near sea level.

3 Replies to “The secret of Kenyan success: it’s not the hemoglobin”

  1. Thanks for this post. This science confirms my unshaking believe that the Kenyan phenomenon is much less genetic than people think. I truly believe it is a result of childhood lifestyle and even more culture as those two go hand in hand. They way they live and grow up is perfect for maintaining a razor sharp running economy I believe that even their running form is developed from their childhood activities. Most of the runners have such naturally developed balanced core and back muscles which allows them to float along the ground in a great position. Where as we who build those up after childhood are at a disadvantage. Hence why there are so many young kenyan phenoms. Sometimes Kenyan runners get slower in what is supposed to be their peak with lifestyle change because the above factors deteriorate. The western world is 10 steps behind in all these things and that is not going to change anytime soon unless Kenya becomes a fully developed country. However these conclusions are not scientific just derived from gathered info and living there and paying attention for logical cause and effect. I have tons more specific activity related theories but that would end up being a small book. Most of thes above observations arent new at all and have been preached, but in the end most people still seem to say genetics as a cop out.

  2. Steve, I thought the weight thing was funny too. The paper was pretty casual about it, as if packing on almost seven pounds is barely worth mentioning! They claim the training volume didn’t change between Kenya and Germany. What they do say is:

    “The increase in renal water retention due to the inhibition of atrial natriuretic factor secretion (8) and stimulation of aldosterone release (32) is also reflected by the augmentation in body mass (Fig. 1). The total increase in lean body mass of 2.0 T 1.0 kg is presumably due mainly to an augmentation in body water content. The increase in fat mass could be related to the unfamiliar and higher caloric German food that the athletes were forced to adapt to by their Kenyan trainer and manager.”

    Lots of fancy words there. Of course, I’ve heard lots of anecdotes over the years of guys packing on pounds as soon as they get to Europe or NA because they’re suddenly in an unfamiliar dietary environment — both different foods, and unlimited quantities available. It doesn’t change anything about this study, but it does tell us that there are some pretty major differences between what Kenyans typically eat and what Germans eat!

    Francis, thanks for the comments. I’m really uncertain what to think about this question. On the one hand, I agree with you about the overwhelming number of non-genetic factors that can explain the differences. On the other hand, the excellence is so concentrated — not just in one country or one region, but primarily in one or two subgroups of one tribal group — that I can’t help but wonder. I’m reading up right now (for other reasons) on Noakes’ central governor theory, which would argue that the limits of performance have a far greater neural component than we’ve recognized so far. It makes me more open to the powerful role that cultural reinforcement can make — not just on encouraging runners to train, but in allowing them to run closer to their physical limits because they’ve internalized that such things are possible.

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