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Howard G. Smith, M.D. is a former radio medical editor and talk show host in the Boston Metro area.  His "Medical Minute" of health and wellness news and commentary was a regular weekday feature on WBZ-AM, WRKO-AM, and WMRE-AM.   His popular two-way talk show, Dr. Howard Smith OnCall, was regularly heard Sunday morning and middays on WBZ.

Trained at Harvard Medical School and a long-time faculty member at Boston Children’s Hospital, he practiced Pediatric Otolaryngology for 40 years in Boston, Southern California, and in central Connecticut.

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Please note that the news, views, commentary, and opinions that Dr. Smith provides are for informational purposes only.  Any changes that you or members of your family contemplate making to lifestyle, diet, medications, or medical therapy should always be discussed beforehand with personal physicians who have been supervising your care.

Aug 2, 2019

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When you exercise for stronger muscles and increase your numbers of muscle strength fibers, you produce a neurotransmitter called Brain-Derived Neurotrophic Factor or BDNF.  This messenger then drives atrophy of your endurance muscle fibers.  


This Yin-Yang relationship is newly described in a study from  Switzerland’s University of Basel.  This BDNF chemical is produced by the muscle itself in response to strengthening exercises.  It triggers remodeling of muscle from slow-twitch endurance fibers into fast-twitch strength fibers.


The investigators also showed that lower levels of BDNF in the muscles of seniors was associated with less decline of muscle bulk with aging.  That would suggest strength training is contraindicated for our elders.


Julien Delezie, Martin Weihrauch, Geraldine Maier, Rocío Tejero, Daniel J. Ham, Jonathan F. Gill, Bettina Karrer-Cardel, Markus A. Rüegg, Lucía Tabares, Christoph Handschin. BDNF is a mediator of glycolytic fiber-type specification in mouse skeletal muscle. Proceedings of the National Academy of Sciences, 2019; 201900544 DOI: 10.1073/pnas.1900544116


#Strength #endurance #BDNF #muscleatrophy