Although scarce , the data available to date suggest that hyper and rogenism , such as that observed in PCOS , may likely be associated with oligomenorrhoea in exercising women , and may not always represent hypothalamic inhibition secondary to an energy deficiency .
To date , the predominant mechanism underlying  menstrual disturbances in exercising women supports an underlying energy deficiency-related aetiology , in which a failure to compensate dietary intake for the energy cost of exercise suppresses reproductive function .
Increasing evidence demonstrates that energy deficiency plays a causal role in the induction of amenorrhoea in  exercising women , and consistent with this mechanism are findings of glucoregulatory perturbations such as low triiodothyronine , reduced insulin secretion and elevated cortisol , growth hormone and ghrelin levels .
The menstrual disturbance that may differ in its energetic characteristics and , perhaps in its and rogenic and ovarian steroid environment , is oligomenorrhoea .
We conducted a systematic review of the literature to begin to underst and whether oligomenorrhoea in  exercising women is a mild sub clinical phenotype of polycystic ovarian syndrome ( PCOS ) in which exercise is conferring beneficial effects in protecting women from the classic PCOS phenotype , or whether oligomenorrhoea is part of the spectrum of menstrual disturbances caused by an energy deficiency that is often reported in exercising women with menstrual disturbances .
Structured exercise training programme versus hypocaloric hyperproteic diet in obese polycystic ovary syndrome patients with anovulatory infertility: a 24-week pilot study.
BACKGROUND Lifestyle modifications are successfully employed to treat obese and overweight women with polycystic ovary syndrome ( PCOS ) . The aims of the current pilot study were ( i ) to compare the efficacy on reproductive functions of a structured exercise training ( SET ) programme with a diet programme in obese PCOS patients and ( ii ) to study their clinical , hormonal and metabolic effects to eluci date potentially different mechanisms of action . METHODS Forty obese PCOS patients with anovulatory infertility underwent a  SET programme ( SET group , n = 20 ) and a hypocaloric hyperproteic diet ( diet group , n = 20 ) . Clinical , hormonal and metabolic data were assessed at baseline , and at 12- and 24-week follow-ups . Primary endpoint was cumulative pregnancy rate . RESULTS The two groups had similar demographic , anthropometric and biochemical parameters . After intervention , a significant improvement in menstrual cycles and fertility was noted in both groups , with no differences between groups . The frequency of menses and the ovulation rate were significantly ( P < 0.05 ) higher in the SET group than in diet group but the increased cumulative pregnancy rate was not significant . Body weight , body mass index , waist circumference , insulin resistance indexes and serum levels of sex hormone-binding globulin , and rostenedione and dehydroepi and rosterone sulphate changed significantly ( P < 0.05 ) from baseline and were significantly different ( P < 0.05 ) between the two groups . CONCLUSIONS Both SET and diet interventions  improve fertility in obese PCOS patients with anovulatory infertility . We hypothesize that in both interventions an improvement in insulin sensitivity is the pivotal factor involved in the restoration of ovarian function but potentially acting through different mechanisms
Although scarce , the data available to date suggest that hyper and rogenism , such as that observed in PCOS , may likely be associated with oligomenorrhoea in exercising women , and may not always represent hypothalamic inhibition secondary to an energy deficiency .
To date , the predominant mechanism underlying  menstrual disturbances in exercising women supports an underlying energy deficiency-related aetiology , in which a failure to compensate dietary intake for the energy cost of exercise suppresses reproductive function .
Increasing evidence demonstrates that energy deficiency plays a causal role in the induction of amenorrhoea in  exercising women , and consistent with this mechanism are findings of glucoregulatory perturbations such as low triiodothyronine , reduced insulin secretion and elevated cortisol , growth hormone and ghrelin levels .
The menstrual disturbance that may differ in its energetic characteristics and , perhaps in its and rogenic and ovarian steroid environment , is oligomenorrhoea .
We conducted a systematic review of the literature to begin to underst and whether oligomenorrhoea in  exercising women is a mild sub clinical phenotype of polycystic ovarian syndrome ( PCOS ) in which exercise is conferring beneficial effects in protecting women from the classic PCOS phenotype , or whether oligomenorrhoea is part of the spectrum of menstrual disturbances caused by an energy deficiency that is often reported in exercising women with menstrual disturbances .