{"id":7190,"date":"2017-03-26T02:29:04","date_gmt":"2017-03-26T01:29:04","guid":{"rendered":"http:\/\/stg-blogs.bmj.com\/bjsm\/?p=7190"},"modified":"2017-03-26T02:29:04","modified_gmt":"2017-03-26T01:29:04","slug":"optimal-health-including-female-athletes-part-1-bones","status":"publish","type":"post","link":"https:\/\/stg-blogs.bmj.com\/bjsm\/2017\/03\/26\/optimal-health-including-female-athletes-part-1-bones\/","title":{"rendered":"Optimal health: including female athletes! Part 1 Bones"},"content":{"rendered":"

Part-1 of the blog mini-series on RED-S<\/span><\/strong><\/p>\n

By Dr Nicky Keay<\/strong><\/p>\n

It is hard to dispute that\u00a0women are underrepresented in medical research and certainly there are not many studies that\u00a0include female athletes. Does this matter? After all whatever your gender, the same physiological and metabolic processes occur. However, the Endocrine system is where there are distinct differences in sex steroid production, which in turn have different\u00a0responses in multiple target cells.<\/p>\n

Although\u00a0studies on changes in exercise performance in response to various dietary interventions and training regimes are often very interesting and well described, I am left feeling slightly uneasy when\u00a0the subjects are all males.\u00a0The\u00a0cause for my concern is that the female hypothalamus-pituitary-ovarian axis is a particularly sensitive system with complex feedback loops and interacting networks.<\/p>\n

Menstrual disturbance is\u00a0not\u00a0unusual amongst women in sport\/dance where low body weight is an advantage. When a ballet dancer performs pointe work, putting full body weight through the big toe is hard enough, without extra load! Some women might consider it a convenience to be\u00a0spared the hassle of\u00a0menstruation. At age\u00a024<\/em>, I was\u00a0perfectly fine never having had a period (primary amenorrhoea), or so I thought, being no more tired than other hospital medical colleagues working full time, studying for postgraduate medical exams and also involved in exercise training.<\/p>\n

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While working as a SHO at Northwick Park Hospital, I volunteered to be included in a study at the British Olympic Medical Association. The study was of female lightweight rowers and ballet dancers to look at VO2 max, percentage body fat\u00a0and bone mineral density (BMD). I had been doing Ballet intensively (and obsessively) from\u00a0a very young age, together with restricted fat and carbohydrate intake. Sounds a\u00a0familiar scenario? Although I looked perfectly healthy (and I did not fit into a clinical condition requiring treatment), worked and danced well, my bone density was worryingly low. So if you are a female doing weight-bearing exercise or resistance training which\u00a0loads the skeleton, these activities promoting\u00a0osteogenesis will be negated if you are not ovulating and producing adequate oestrogens. The female athlete triad composed of disordered eating, amenorrhoea and low BMD was originally described by Drinkwater in 1984.\u00a0However, once pathological states causing amenorrhoea have been excluded, in medical terms the female athlete triad did not necessarily constitute a disease state\u00a0requiring intervention, rather subset of the “normal population”.<\/p>\n

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How significant is\u00a0having low BMD compared to the age-matched population during your 20s? Could this even be viewed as a reversible adaptation to training, reflected in\u00a0site specific\u00a0differences in BMD according to sport? After all, when female athletes retire with\u00a0decreased training “stress” and more “relaxed” diet, menses often resume and therefore does BMD also improve? This was the question I sought to answer in my study on 57 premenopausal retired professional dancers. Even with return of menses, if these athletes had experienced previous amenorrhoea of more than 6 month duration, then bone loss was irrecoverable. Current low BMD was also correlated\u00a0to lowest body weight (independent of amenorrhoea) during dance career and later age of menarche. There did not appear to be any protective effect of being on the oral contraceptive pill. Constructing a model of BMD using multiple regression 33.6% of total variation in z (age matched) score for BMD at lumbar spine was accounted for by duration of amenorrhea, age at menarche and lowest body weight during dance career. So “athletic” hypothalamic amenorrhea rather than being a reversible, adaptive response has long term, irreversible effects on BMD.<\/p>\n

Apart from bone metabolism, what other systems are impacted by mismatch of energy intake and expenditure in overtly healthy athletes?\u00a0Are\u00a0the\u00a0endocrine and metabolic systems in male athletes also affected by subtle imbalances in training energy expenditure\u00a0and dietary intake? What about young athletes? In my next blog I will explore the rationale behind the original female athlete triad now being described as part of Relative Energy Deficiency in sports (REDs). The implications for current\u00a0health and sports performance, as well as long term health in both adult men and women and young athletes.<\/p>\n

References<\/strong><\/p>\n

Keay N, Fogelman I, Blake G. Bone mineral density in professional female dancers. British Journal of Sports Medicine, vol 31 no2, 143-7, June 1997.<\/p>\n

Keay N. Bone mineral density in professional female dancers. IOC World Congress on Sports Sciences. October 1997.<\/p>\n

Keay N, Bone Mineral Density in Professional Female Dancers, Journal of Endocrinology, November 1996, volume 151, supplement p5.<\/p>\n

Keay N, Bone Mineral Density in Female Dancers, abstract Clinical Science, Volume 91, no1, July 1996, 20p.<\/p>\n

Keay N, Dancers, Periods and Osteoporosis, Dancing Times, September 1995, 1187-1189<\/p>\n

Keay N, A study of Dancers, Periods and Osteoporosis, Dance Gazette, Issue 3, 1996, 47<\/p>\n

Fit to Dance? Report of National inquiry into dancers\u2019 health<\/p>\n

Fit but fragile. National Osteoporosis Society<\/p>\n

Your body your risk. Dance UK<\/p>\n

From population based norms to personalised medicine: Health, Fitness, Sports Performance<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Part-1 of the blog mini-series on RED-S By Dr Nicky Keay It is hard to dispute that\u00a0women are underrepresented in medical research and certainly there are not many studies that\u00a0include female athletes. Does this matter? After all whatever your gender, the same physiological and metabolic processes occur. However, the Endocrine system is where there are […]<\/p>\n

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