lunes, 30 de agosto de 2010

Cardiac adaptation in elite female athletes

A study conducted in the UK has established the extent of cardiac adaptation amongst female athletes competing in a number of sports. Previous studies of cardiac adaptation have been conducted only on male athletes, yet a growing number of females participate at elite level in many sports, nowadays including some such as rugby and boxing that were traditionally undertaken only by males. The results show evidence of changes to the heart, particularly to ventricle wall thickness and cavity size. In addition, the study considered whether ethnicity was a factor in the degree of measured cardiac adaptation.
The study was led by Professor Sanjay Sharma, of St. Georges University, London where he is Professor of Cardiology. He is also a member of the ESC’s European Association for Cardiovascular Prevention and Rehabilitation (EACPR), and Medical Director of the London Marathon. “Female athletes do not exhibit the same extent of cardiac adaptation as males. This is because they tend to be smaller and leaner with a lower body mass, and do not reach the same levels of exercise intensity,” he says. “Also, due to the physical differences in chest wall morphology, the typical QRS complexes of females measured on a 12-lead ECG are much less pronounced. The purpose of this study was to determine what changes do occur in elite female athletes that undertake an intensive training regime.”

The study has resulted in four findings:

-Females that engage in regular sport show modest increases in left ventricular wall thickness and cavity size when compared to sedentary females
-The magnitude of left ventricular wall thickness and cavity size is a function of many demographic factors including age and size, as well as the sport undertaken

-In absolute terms, the realistic limits tend to be <11mm>
In order to extend the relevance of the findings to other ethnic groups, the study examined and investigated existing research but discovered that there is limited published data available. One report that compared Caucasian male athletes with African and Afro-Caribbean male athletes suggests that Caucasians have lower left ventricular hypertrophy (LVH) and a lesser prevalence of re-polarisation for very similar group demographics and sporting disciplines.
This finding was confirmed in very important work¹ that was recently published which compared around 200 nationally ranked female athletes from each of these two ethnic groups. Researchers established that black females selected from across 10 sporting disciplines exhibited a greater magnitude of LVH than their white counterparts. 3% of them showed a left ventricle wall thickness of >11mm (typically 12 to 13mm) whereas none of the white athletes exceeded 11mm. 15% of black athletes demonstrated re-polarisation changes compared with just 2% of the white athletes. The study concluded that standardised criteria derived from white athletes could unfairly discriminate against black athletes by leading to unnecessary investigation or even disqualification.