menstrual problems

The physiological and aesthetic demands of synchronised swimming are similar to those of gymnastics and dancing. But do synchronised swimmers suffer menstrual disturbance to the same extent as female gymnasts and dancers - or do they have more in common with conventional swimmers, who are relatively protected from the 'female athletic triad' of disordered eating, amenorrhoea (absent periods) and osteoporosis?

These are the questions a pair of researchers from the British Olympic Medical Centre set out to answer with a study of the Great Britain synchronised swimming squads. Seven members of the senior squad and 16 of the junior squad filled in a questionnaire designed to assess the normality of their menstrual cycles and also underwent a range of physiological tests.
Analysis revealed that only three of the subjects were oligomenorrhoeic (with menstrual cycles longer than 35 days) and none were amenorrhoeic. The mean age of menarche (onset of menstruation) was 13.7 years. Mean estimated body fat percentage was 23% and mean VO2max was 47.2ml/kg/min.

'Synchronised swimmers share certain physiological characteristics with gymnasts and dancers, who have a high incidence of amenorrhoea,' the authors point out. 'However, they also share other features with conventional swimmers, who have a low incidence.

'Furthermore, the mean age of the menarche in this group (13.7 years) is midway between the age seen in non-athletes (12.8 years) and in other Olympic athletes (14.8 years). There is therefore little evidence from this study that synchronised swimming training significantly increases the risk of menstrual abnormalities.'

Why then are synchronised swimmers and swimmers in general apparently protected from menstrual abnormalities? The researchers point to three main theories:

1. immersion in cool water during exercise may allow swimmers to control their core temperature in such a way as to prevent disruption to the intricate physiological systems which control menstruation;

2. both conventional and synchronised swimmers have relatively high levels of body fat, which is known to protect against amenorrhoea;

3. swimmers do not engage in the combination of disordered eating and intensive training to the same extent as other athletes with menstrual disturbances.

Synchronised swimming, then, does not compromise bone density. However, as the researchers point out, since training for this sport is mainly non-weight bearing, it doesn't build stronger bones either.

Br J Sports Med 2001 Aug 35(4), pp242-244

Isabel Walker