A researcher in Sweden has discovered that a common congenital cause of menstrual disorder may help female athletes succeed by slightly raising their testosterone level.

The study was the doctoral thesis of Magnus Hagmar, a postgraduate with the Department of Woman and Child Health at the Swedish medical university Karolinska Institutet in Stockholm.

“What we’re dealing with is just a tiny increase in levels, which can make it easier for the women to build muscle mass and absorb oxygen,” said Hagmar.

“This means that they might have got quicker results from their training and therefore been encouraged to train harder and more often,” he added.

Hagmar said his finding could overturn old notions that strenuous physical activity such as in elite sports can damage women’s health.

The condition that causes menstrual disorder and slightly raises testosterone is called polycystic ovary syndrome (PCOS), and it is not uncommon. PCOS is a hormone irregularity and a leading cause of infertility among women.

During his research Hagmar found that not only is PCOS a common cause of menstrual disorders among elite Olympic athletes, but there was a higher incidence of polycystic ovaries among Olympic female athletes (37 per cent) compared with women in general (20 per cent).

Altogether Hagmar, who is assistant senior physician at the women’s clinic at Karolinska University Hospital, examined 233 men and women who had competed in the 2002 and 2004 Olympic Games, and 90 women who are training for the 2008 Games.

Even among female athletes, Hagmar found significant differences:

“It’s particularly interesting that the percentage of women with polycystic ovaries was higher in power sports like ice hockey and wrestling than in technical sports like archery and curling,” he said.

Hagmar said the results were not confounded by doping, since all 90 female athletes included in his study had taken regular drug tests that came up negative.

In detail, the studies that Hagmar conducted showed that:

  • Among the 223 Swedish athletes who took part in the 2002 and 2004 Olympic Games, those participating in sports that emphasize leanness showed less desirable weight control and more frequent illness than competitors in other disciplines, particularly the men.
  • Among 90 of the women, and especially the endurance athletes, menstrual dysfunction was frequent.
  • The most common cause of menstrual dysfunction was PCOS, rather than hypothalamic inhibition (inhibition of the hormone regulating gland in the brain).
  • No signs of chronic energy deficiency were observed, based on evaluation of body fat content and biomarkers of energy availability.
  • Bone mineral density (BMD) was generally high and none of the female athletes exhibited osteopenia or osteoporosis.
  • Among 20 postmenopausal former elite athletes there was enhanced endothelial function in those not using hormone therapy.
  • Among those who did use hormone therapy, this was linked with endothelial function similar to that of sedentary women (controls).
  • Blood levels of cholesterol and low-density lipoprotein (the “bad” cholesterol), body fat content were lower in former athletes compared with controls.
  • Exercise capacity, left and right cardiac ventricles, and left atrial and stroke volumes were all significantly greater among the former elite athletes than among the controls.

Hagmar concluded that:

“Our findings challenge the contemporary concept that reproductive dysfunction in sportswomen is typically a consequence of chronic energy deficiency.”

“Here, the single most frequent underlying cause of menstrual disturbances in Olympic athletes was the hyperandrogenic disorder PCOS. Long-term strenuous exercise is associated with minor changes in cardiac structure, but overall beneficial effects on exercise capacity, vascular function and cardiovascular risk factors,” added Hagmar.

For some time, there has been a belief among scientists that tough training, combined with low energy intake, is linked to menstrual disorder in elite female athletes, a phenomenon often referred to as the “female athlete triad”.

This idea was brought into popular awareness in Ridley Scott’s film GI Jane, where Demi Moore plays Lieutenant Jordan O’Neil, a communications officer who is chosen to be the first female member of the US Navy’s SEAL program, considered to be the most demanding military training in the world. In the film, O’Neil stops menstruating, which a medical officer who examines her during a check up explains is due to the hard physical training.

The female athlete triad has also been linked to low bone density (osteopenia), thought to be due to low levels of oestrogen. But Hagmar’s results showed that elite female athletes have very strong bones, despite having menstrual disorders.

Hagmar also concluded that where low body weight is an advantage, such as in certain sports, female athletes generally have a healthier way to control their weight, compared to their male colleagues.

While he could not completely rule out low energy intake as a factor in causing menstrual disorder in elite sportswomen (there was one case among the participants in his study), it is far from being the most common cause.

“The fact that not a single woman had low bone density takes away one of the factors of the female athlete triad.”

“Menstrual status and long-term cardiovascular effects of intense exercise in top elite athlete women.”
Magnus Hagmar.
Doctoral thesis, published online 18 April 2008.
ISBN: 978-91-7357-549-2

Click here for Abstract and download link to the full thesis.

Source: Karolinska Institutet.

Written by: Catharine Paddock, PhD