Hemoglobin is responsible for carrying oxygen around to active tissues. On average, hemoglobin levels are 12% higher in males than females, which is thought to be due to the effect of testosterone.
pubmed.ncbi.nlm.nih.gov/19494706/
New research paints a clearer picture that trans women do lose significant performance in just a few short months of commencing HRT.
lboro.ac.uk/departments/ss…
Since 2019, Joana Harper has been based at Loughborough University in the U.K. as part of a project using science and research to aid policy making.
The university’s latest research, looks at how the protein in our red blood cells that helps oxygen flow to our muscles for aerobic activity is affected by hormone replacement therapy in trans women.
lboro.ac.uk/departments/ss…
Loughborough University’s findings show the hemoglobin level in transgender women falls to levels in line with cisgender women in the space of three to four months on average.
That is a huge change and it affects all endurance sports, and, in fact, any sport where you were being active for more than a few minutes.
The hemoglobin level in your blood is important for taking up and using oxygen in your muscles heart& lungs. It’s perhaps the single most important reason that men outperform women in endurance events, because of the higher hemoglobin level.
For those who suggest trans women have advantages: we allow advantages in sport, but what we don’t allow is overwhelming advantages.
Trans women also have disadvantages in sport. Our larger sometimes larger bodies are being powered by reduced muscle mass and reduced aerobic capacity, and can lead to disadvantages in quickness, recovery and a number of other factors.
The bottom line is, we can have meaningful competition between trans women and cis women. From my point of the view, the data looks favorable toward trans women being allowed to compete in women’s sports.
bjsm.bmj.com/content/early/…

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More from @KirstiMiller30

9 Jun
Former elite athlete Kristen Worley, a New Zealander based in Canada, has been working with the International Olympic Committee on its transgender guidelines for the past 18 months and is considered an expert in trans experience in sport.
stuff.co.nz/sport/women-in…
She said the reduction of hormones and “sex reassignment” can have a “catastrophic impact” on the body of transgender people.

@PaulSimon1971 this is what others argued with me ✊
“Under the current rules ... this is just above the level [of testosterone] where the body starts to fail. It’s like taking the gas out of the car,” she told Stuff.

@CydZeigler, @CarolineLayt what we were discussing & what I have advocated for years now with very few listening
Read 26 tweets
9 Jun
@Quizical15 @AnnaVolodova @madina_wane @DrJoGrady @XineYaoPhD Despite the many assumptions about the relationship between testosterone and athletic advantage, there is no evidence showing that successful athletes have higher testosterone levels than less successful athletes.
@Quizical15 @AnnaVolodova @madina_wane @DrJoGrady @XineYaoPhD Still, the IAAF continues to use testosterone levels to determine who is eligible for the women’s division. In the recent case between the IAAF & Caster Semenya, the IAAF produced data suggesting that women with testosterone levels in the highest tertile (one third...
@Quizical15 @AnnaVolodova @madina_wane @DrJoGrady @XineYaoPhD had a competitive advantage compared to women competitors with testosterone levels in the lowest tertile.
Read 26 tweets
9 Jun
There are biological differences between men and women.

Height:

Muscle Mass:

Strength:

Power:

Body Fat:

Hemoglobin

Testosterone:
Height: On average, men tend to be 10-15 cm taller than women. It is thought that testosterone release during puberty is responsible for the average greater height in men.
Courant 2010
Muscle Mass: On average, men tend to carry 30-40% more lean body mass than women (this includes muscle, organ, bone, water, and all other non-fat mass).Janssen 2000
Read 52 tweets
9 Jun
A paper by Wiik et al, looked at strength and muscle mass levels in 11 MTF (trans women) and 12 FTM (trans men) individuals over 1 year of transitioning.
As seen in Figure 8, the authors compared the transgender individuals’ muscle torque and muscle volume to cisgender controls.
It is not clear if these controls had similar activity levels, dietary intakes, and/or completed the same strength testing protocols as the transgender subjects.
Read 11 tweets
8 Jun
Despite the many assumptions about the relationship between testosterone and athletic advantage, there is no evidence showing that successful athletes have higher testosterone levels than less successful athletes.
Still, the @WorldAthletics continues to use testosterone levels to determine who the women’s division. It must be noted the @WorldAthletics does not regulate the testosterone levels of any XX women even though their own evidence showed XX women are more sensitive to androgens.
In the case between the IAAF & Semenya, the IAAF produced data suggesting that women with testosterone levels in the highest tertile (one third) had a competitive advantage compared to women competitors with testosterone levels in the lowest tertile.
Read 13 tweets
8 Jun
Australia under Morrison now gaols adults at the highest rate since the convict days.
The return to mass incarceration in Australian prison population does not due to crime rates, which have mostly declined over the past generation.
Instead, failing to implement the majority of the RC recommendations for 30yrs, higher reporting rates, stricter policing practices, tougher sentencing laws, and more stringent bail laws appear to be the main drivers of Australia’s growing prison population.
Read 9 tweets

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