|With only one female power lifter and fewer female athletes for all sports, I didn't copy the hardly legible data for them, as well.|
The research question M.J. Healy and colleagues from the St James’s Hospital, the Tallaght Hospital and the University of Exeter in Ireland and the UK tried to answer is thus: "What's actually normal for someone who's voluntarily exposing his body to hardships with profound endocrine side effects."
It goes without sayin' that the answer to this question is of particular interest for the WADA, the World Anti Doping Association. Whether it's also relevant for the average gymbro, on the other hand, is something I want to discuss in the bottom line of this article and thus after we've taken a closer look at the main results, of which the extremely low testosterone : estrogen ratio in powerlifters I already mentioned in the previously cited Facebook post is just one out of several curiosities.
|Figure 1: Endocrine parameters relative to minimum (% above the bars) and maximum of reference range (bars) for men; the data is based on a barely legible table from the manuscript version and subject to correction (Healy. 2014)|
In a totally different context, Maïmoun et al. (2014) have only recently been able to show that the endocrine profile of female swimmers "was characterized by significantly increased serum T levels (0.56 ng/mL, vs 0.39 ng/mL for controls) - to be precise, "[s]eventy-two percent of these swimmers presented T values higher than 0.5 ng/mL, characterizing this population as hyperandrogenic" (Mïmoun. 2014). A percentage that's high enough for the French researchers to conclude that...
"[...] in these female athletes is perhaps not coincidental (16). A predisposition to hyperandrogenism might orient girls toward sports like swimming, where strength is a performance criterion." (Maïmoun. 2014)Whether a similar explanation could be given for the extremely low testosterone levels of the powerlifters is highly questionable. There is after all no sex-difference in respect to the impact and importance of testosterone in strength sports that would dictate that women need abnormally high testosterone and abnormally low estrogen levels, while men need low testosterone and high estrogen levels for maximal strength performance.
Apropos men and women: There are similar extremes
If we stick to the analysis of abnormal testosterone levels, it appears as if excursions to both extremes are about equally likely in men and women, with...
- 16.5% of the male athletes suffering (?) from serum testosterone levels below 8.4 nmol/l, the lower limit of the normal reference range (Bayer. 2013), and
- 13.7% of the female athletes exposing testosterone levels greater than 2.7 nmol/l, the upper limit of the normal reference range (Bayer. 2013)
Doping excluded: With one exception, all athletes with low testosterone levels had normal luteinizing hormone (LH) levels - a clear indicator that they were not using performance enhancing drugs like trenbolone, or nandrolone, which would obviously crush both, the T- and LH-levels.For the women with testosterone levels above the normal range (> 8.3nmol/l) the scientists observed significant differences in fat mass, height, estradiol fT3, fT4, %body fat, BP2, Osteocalcin and IGF-I. Specifically, the women with elevated testosterone levels were...
- taller and thinner,
- had lower estradiol, IGF-1 and osteocalcin levels, but
- increased free T3, free T4 an IGFBP2 levels
Sport is not just one, it's the most significant determinant of endocrine disturbances
Irrespective of the fact that we have to be similarly cautious on the other end of the high vs. low testosterone level divide, the mere age-difference between the oldest athletes, the power lifters, and the youngest, the swimmers, is similarly unsuited to explain the differences I plotted in Figures 1-2 (note: I decided against plotting the data for the female athletes, because (a) the table was even harder to read and (b) the number of athletes in many sports was very low), as the height (basketball players were the tallest and the power lifters the shortest) and weight differences (contact sports like ice hockey, handball and basketball had the highest BMI while cross-country skiing the lowest). In fact, Healy et al. found only two instances where age alone could account for the differences between sports (IGF-BP2 and IGF-BP3 in women).
|Figure 2: Power lifters don't even have the lowest testosterone : estrogen ratio, track & field athletes are - assuming that I deciphered their estrogen levels correctly, even worse off (Healy. 2014)|
"For example, there was the inevitable relationship between height, weight, body fat, lean body mass (LBM) and BMI. Weight correlated very closely with BMI which in turn correlated less closely with LBM, body-fat and height. For LBM and body-fat the relationship with BMI is distinctly different between the sexes reflecting the increased body fat in women at all levels of BMI." (Healy. 2014)And while I know that you would probably like to hear more about the underlying mechanisms, an observational study like the one at hand simply doesn't allow for a detailed analysis of the general mechanism behind this complex network of changes.
- Aakvaag, A., et al. "Hormonal changes in serum in young men during prolonged physical strain." European journal of applied physiology and occupational physiology 39.4 (1978): 283-291.
- Bayer Diagnostics. Total (Serum) Testosterone by Advia Centaur System (2013). Ref Type: Online Source: labmed.ucsf.edu/labmanual/db/resource/Centaur_Testosterone.pdf
- Bennell, Kim L., Peter D. Brukner, and Susan A. Malcolm. "Effect of altered reproductive function and lowered testosterone levels on bone density in male endurance athletes." British journal of sports medicine 30.3 (1996): 205-208.
- Healy, M. L., et al. "Endocrine Profiles in 693 Elite Athletes in the Post‐Competition Setting." Clinical endocrinology (2014).
- IOC Regulations on Female Hyperandrogenism (2012). Ref Type: Internet Communication: www.olympic.org/Documents/Commissions_PDFfiles/Medical_commission/2012-06-22-IOC-Regulations-on-Female-Hyperandrogenism-eng.pdf
- Maïmoun, Laurent, Neoklis A. Georgopoulos, and Charles Sultan. "Endocrine Disorders in Adolescent and Young Female Athletes: Impact on Growth, Menstrual Cycles, and Bone Mass Acquisition." The Journal of Clinical Endocrinology & Metabolism (2014).