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Is the new professionalism and ACP's new ethics really just about following guidelines?

The Charter ( Medical Professionalism in the New Millennium.A Physician's Charter) did not deal with just the important relationship of ...

Tuesday, March 06, 2018

What does reduced ejection fraction in elete athletes mean?

Some NBA  and  professional European cyclists (1) have been shown to have reduced cardiac ejection fractions (EF) and some NFL players(2 )have EFs in the lower range of normal. In regard to the cyclists this observation has , at least in one review, been used to bolster the argument that "too much exercise" is harmful , i.e. support for the  "U-Shaped" curve theory."Too much " exercise certainty can be harmful  (maybe that is what "too much" means) but reduced resting EF in elite . athletes is not proof of that contention.

The wisdom of the body may dictate that maintenance  of stroke volume a priority and not EF. These athlete have large preloads ( aka end diastolic volumes) so that a smaller percentage can be ejected to maintain the resting stroke volume. These basket ball players had a normal increase in stroke volume  and EF with exercise as did the NFL players.I believe the exercise EF was not measured in the cyclists.

1.Abergel, E. Serial left ventricular adaptations in world -class professional cyclists.J AM Coll Cardiology July 2004.
2. Abernethy,WB Echocardiographic characteristics of professional football players.JACC Jan 2003 p 280
3)Engel,D Athletic cardiac remodeling in U.S. professional basket ball players. JAMA Cardiol 2016, (1) 80-87 

Monday, March 05, 2018

Reversing cardiac aging-maybe some but it isn't easy

More about cardiac aging and aerobic exercise  from the Institute for Exercise and  Environmental Medicine  is found  the January 2018 issue of Circulation. Howden et al(1) report the results of a two year trial of a vigorous exercise program on various physiological measurements.

They were able to show some improvement in cardiac compliance ( i.e. a decrease in myocardial stiffness) in a group of middle aged,otherwise healthy subjects over a 2 year period but the exercise required was considerably more than frequent brisk walks or slow jogs around the park.Rather , part of the exercise program involved a vigorous high intensity interval program using the "4 by 4 " Norwegian Skier technique twice a week and later in program only once a week.

Dr. Ben Levine, the Director of the Institute, and his team seemed to be able to recruit subjects who would persevere in a demanding exercise program over a 2 year program  and   to also permit right heart catheterizations which were done to give the investigators a index of compliance of the left ventricle.The bottom line is that they were able to demonstrate a reduction in cardiac stiffness with their exercise program .

This study is the most recent in a series of publications which have demonstrated that there is some level of prolonged endurance exercise that can at least to some degree mitigate the age related loss of cardiac compliance . Previously they had attempted to improve cardiac compliance in older subjects (in their 70's) and were unsuccessful. In this study they hoped they could find a "sweet spot", a time frame in which it was not loo late to reverse the age driven stiffness and they seemed to have , at least to some measurable degree succeeded .

Levine characterizes the sedentary heart as a "small, stiff heart" versus the endurance athlete's heart as larger,slightly thicker and more compliant.

Levine describes the stages in the aging of the heart :1) loss of relaxation ,2) stiffening ( beginning in middle age), and finally 3) remodeling. The hope is that adequate exercise might mitigate  or significantly delay stage 2 which may be the precursor or  a prerequisite for heart failure with preserved diastolic function. Years of endurance exercise does not seem to prevent the first phase but Levine's data suggest that exercise may counteract the stiffening and remodeling.

1) Howden EJ et al Reversing the cardiac effects of sedentary aging.A randomized trial.Circulation,2018 137; (full text available on line without firewall)