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Muscle Fiber Typing and Race: Redux

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JP Rushton

Richard Lynn

L:inda Gottfredson


I recently blogged on Muscle Fiber Typing, HBD, and Sports. I showed that differences in which race wins at what competition comes down to ancestry, which then correlates with muscle fiber typing. I came across this paper, Black and White race differences in aerobic capacity, muscle fiber type, and their influence on metabolic processes, today which, of course, proved my point on muscle fiber typing.

The authors say that obesity is a known risk factor of cardiometabolic disease (though Blüher 2012 says that up to 30 percent of obese patients are metabolically healthy with insulin sensitivity on the same level as thin individuals) and that cardio can reduce excess adipose tissue (this isn’t true either), maintains weight (maybe) and reduces the risk of obesity (it doesn’t) and cardiometabolic disease (this is true). The two major determinants of aerobic capacity are muscle fiber typing and “the capacity of the cardiorespiratory system to deliver nutrient-rich content to the muscle”. As I said in my previous article on muscle fiber typing, depending on which fibers an individual has determines whether or not they are predisposed to being good at endurance sports (Type I fibers) or being good at explosive sports (Type II fibers). Recent research has shown that blacks fiber typing predisposes them to a lower overall VO2 max.

VO2 max comes down to a strong oxygen support system and the capacity to contract a large number of muscle fibers at once, both of which are largely genetic. Lactic acid makes us tired, the best way to train is to minimize lactic acid production and maximize lactic acid removal during exercise. High-Intensity Interval Training, or HIIT, achieves this. The more O2 consumed during exercise, the less of a reliance there will be on the anaerobic breakdown of CHO to lactic acid.

Along with inadequate exercise, these variables place blacks at an increased risk for obesity as well as other negative metabolic factors in comparison to other races/ethnic groups. The author’s purpose of the review was to show how skeletal muscle fiber typing contributes to obesity in non-“Hispanic” black populations.

The review indicates that the metabolic properties of Type II fibers (reduced oxidative capacity, capillary density, which is a physiological measure that takes a cross-section of muscle and counts the number of blood vessels within. The measurement can be considered an indicator of physical health and is also related to the ability to do strenuous activity) are related to various cardiometabolic diseases.

Since non-“Hispanic” blacks have more Type II fibers on average, they have a lower maximal aerobic capacity. Combined with low Resting Energy Expidenture (REE) and reduced hemoglobin concentration (hemoglobin is a protein in the red blood cells that shuttles oxygen to your tissues and organs and transports carbon dioxide from your organs and tissues back to your lungs), non-“Hispanic” blacks may be predisposed (they are when you look at what the differing skeletal muscle fibers do in the body and if you have a basic understanding of physiology) to a lower maximal aerobic capacity, which contributes to obesity and metabolic disease in the non-“Hispanic” black population.

I have written on ethnicity and obesity last year. In the two racial groups that were tested, American non-“Hispanic” whites and American non-“Hispanic” blacks, what the researchers say holds true.

On the other hand, Kenyans have an average BMI of 21.5. Since we know that a high VO2 max and low BMI are correlated, this is why Kenyans succeed in distance running (along with VO2 max training, which only enhances the genetic effects that are already there).

Moreover, I wrote an article on how Black American Men with More African Ancestry Less Likely to Be Obese. How do we reconcile this with the data I have just written about?

Simple. The population in the study I’m discussing in this article must have had more non-African ancestry than the population that was gathered showing that black American men with more African ancestry are less likely to be obese. The researchers in that study looked at  3,314 genetic markers. They then tested whether sex modifies the association of West African genetic ancestry and body mass index, waist circumference, and waist to hip ratio. Also, they adjusted for income and education as well as examined associations of ancestry with the phenotypes of males and females separately. They conclude that their results suggest that a combination of male gender and West African ancestry is correlated with protection against central obesity and suggests that a portion of the difference in obesity (13.2 percent difference) may be due, in part to genetic factors. The study also suggests that there are specific genetic and physiologic differences in African and European Americans (take that, race-denialists =^) ).

Since both black men and women in America share the same environment, some genetic factors are at play in the differences in obesity rates between the two sexes with more African ancestry for black American men being the main reason.

Finally, I wrote an article on BPA consumption and obesity. The sample was on blacks and Dominicans (they’re black as well) in NYC. It was discovered that babes who were exposed to BPA more in childhood and in the womb had higher chances of being obese. This goes with what the authors of the study I’m citing in this article say. There are numerous environmental factors that pertain to obesity that’s not kcal in/out (which the First Law of Thermodynamics is irrelevant to human physiology). BPA consumption is one of them (as well as a cause for the current and ongoing cucking of Europe). Whites at all age groups drink more tap water. Blacks and ‘Hispanics’ were pretty much even in consumption of bottled water. Bottled water has BPA in the plastic, and since they drink more bottled water, they run the risk of their children being more prone to obesity due to the negative effects of BPA in the human body.

In sum, blacks are more likely to be faster due to their fiber typing, but are also more likely to be obese (in this sample, anyway which I assume was a mix of men and women. I will update this article when I find and read the full paper). They also run a higher risk of having related diseases, most notably due to a lower REE (showing they don’t walk around as much, since too much sitting increases mortality EVEN WITH EXERCISE. So if you have a desk job and don’t do any other physical activity and enjoy living, do more LISS, low-intensity steady-state cardio). These factors also, in part, explain why blacks have higher rates of hypertension (with Sickle Cell Anemia being another cause since when the blood is sickle-shaped, they crowd in the blood vessels causing blockage in the veins which leads to strokes and other diseases). The more the genetic factors that predispose people to obesity are understood (let’s be real here, there ARE genetic correlates with obesity), the better we can help those who suffer from the condition.


1 Comment

  1. […] this: Molly Norris. Piousislamophilia. Economics. Lost Souls. Race and fiber. Liberals are bigots. USA = Globalism. […]


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