35th AMAA Medical Symposium at the Boston Marathon[R].
Ever since Dr. Ron Lawrence got this group going, we have been running Boston--and while there, sharing our experiences caring for runners and other athletes. The AMAA Medical Symposium has grown into a nationally recognized and sponsored meeting. Each year, AMAA members have gathered to listen, question, and debate the latest advances in medicine as they relate to running and endurance sports. The tradition continues with this year's symposium.
In presentations and panels, speakers explore how endurance running and other sporting activities affect the body. Topics range from "Obesity and Diabetes" to "Effects of Exercise on the Brain." For the third straight year, a distinguished panel presents the latest findings on the troubling problem of hyponatremia in marathon runners. This year's panel ("Disorders of Hydration: Acute Exertional Dysnatremias, from Kona to Boston") looks at two sides of the over-hydration story. The 35th symposium also looks at medical issues unique to women runners--including Dr. Richard Mayerchak's discussion on running during pregnancy and postpartum.
AMAA is proud of its heritage at the Boston Marathon. Thanks to the leadership of Dr. Ron Lawrence, marathons and other endurance events now offer state-of-the-art medical triage and treatment onsite. Gone are the days when road races and endurance events had to rely on EMT crews as first responders to medical emergencies. This year, as in years past, the Boston Symposium draws medical professionals committed to bettering care for runners and other endurance athletes. For those of you who can't make it to Boston, we share here some of the topics from this year's symposium.
--Dave Watt, Executive Director, AMAA
Physical Exercise and the Brain
Patrick J. Hogan, DO
Puget Sound Neurology
The role of the brain in athletic performance has often been relegated to motivation and the static mechanical generation of muscular activity--while conditioning, strength, speed, and fatigue were considered roles of muscle physiology. It is now recognized that the brain is a dynamic organ that changes in response to conditioning exercise to enhance athletic performance and is largely responsible for fatigue that limits exercise capacity.
Exercise that challenges the brain increases neurochemicals including BDNF (Brain Derived Neurotrophic Factor), serotonin, and dopamine. This leads to increased neuronal development and synaptic activity that enhances brain function, and it serves to improve athletic performance as well as to symptomatically improve, forestall the progression of, and possibly prevent many disease states.
That exercise induces synaptic plasticity of the brain to promote recovery from stroke and trauma has long been accepted as the basis of rehabilitation medicine. Recent evidence has demonstrated that physical activity induces a plasticity of the brain that has a large positive impact on other disorders such as Alzheimer's, Parkinson's, migraine, depression, chronic pain, and fibromyalgia.
The changes in the brain occurring in response to exercise plays an integral role in what is experienced as physical fitness. Muscular strength and speed improve with exertion on a neuronal basis even before changes occur at the muscle level. Fatigue from sustained exertion that was once thought as being only a metabolic muscular process is now recognized as occurring primarily at the level of the brain as a protective mechanism.
Physical exercise as medicine for the brain is one of the foundation principles behind the formation of CHAMP (Coalition for Health Active Medical Professionals) to promote fitness in daily medical practice.
Hydration and Its Disorders: New Understandings, New Treatments
Arthur J. Siegel, MD
Director, Internal Medicine
McLean Hospital, Belmont, MA
Assistant Professor of Medicine,
Harvard Medical School, Boston, MA
In this panel, experts will provide an update on determinants of body fluid homeostasis during endurance exercise. Scott Montain, MD, will present strategies for optimal fluid replacement during marathon running with an emphasis on the dual benefit of sports drinks over water for decreasing the risks of both dehydration and hyponatremia (EAH). The latter condition may occur when the net intake of all hypotonic fluids exceeds losses leading to acute water intoxication. Based on mathematical models to assess variables including body mass index, race pace, weather conditions, and sweat rates, the risks of both dehydration and EAH can be reduced.
Next, Hawaii Ironman Triathlon Medical Director, P.Z. Pearce, MD, will relate his experience in diagnosis and treatment of these disorders in collapsed Ironman-triathlon triathletes including trends since the availability of new sports drinks at these events.
Finally, I will review Boston Marathon studies on the pathogenesis of EAH in collapsed runners including fatal cases. The findings indicate that this condition is caused by a decrease in urine production due to inappropriate secretion of arginine vasopressin (AVP). Understanding EAH as a variant of the syndrome of SIADH means that life-threatening cases require treatment according to well established interventions based on this paradigm. Intravenous hypertonic (3%) NaCl to reverse acute cerebral edema has been used safely and with excellent clinical outcomes in such cases at the 2004-05 Boston and Marine Corps marathons.
Fluid Replacement for Marathon Races
Scott J. Montain, MD
U.S. Army Research Institute of Environmental Medicine, Natick, MA
Reports of marathoners developing symptomatic hyponatremia either during or the initial hours after racing have prompted reevaluation of fluid replacement guidance and event implementation. The purpose of this presentation is to provide practical fluid replacement guidance for marathoners and event organizers. This will include a review of the physiological consequences of under- and over-drinking during exercise and the impact of hydration imbalance on race performance.
A mathematical model will be used to demonstrate the interactive effects of body mass, body composition, running speed, and weather on sweating rate and sweat electrolyte losses; to consider the impact of carbohydrate and electrolyte replacement; and to evaluate the adequacy of newly proposed fluid replacement recommendations for sustaining appropriate hydration during marathon competition.
The outcome will be an appreciation of individuality of sweating rates in runners and the necessity of individual responsibility in managing personal hydration.
Obesity and Type 2 Diabetes in Youngsters: Fighting the Epidemic with Exercise
Jeffrey A. Ross, DPM, MD
Associate Clinical Professor
Baylor College of Medicine
The prevalence of obesity nationwide is increasing among children. In information gathered by the National Center for Health Statistics over four decades, the prevalence of obesity among U.S. children and adolescents aged six to 19 has grown from 4% in 1963 to 15% in 2000. Overweight adolescents have a 70% chance of becoming overweight or obese as adults. If one parent is overweight or obese it increases to 80%.
Additionally, diabetes has reached epidemic proportions nationwide. Not only are the personal and economic tolls rising, but the onset of type 2 diabetes is accelerating. In the coming years, the number of youth expected to be diagnosed with type 2 diabetes stands to triple over the next 25 years. The epidemic of type 2 diabetes amongst these youngsters will be devastating. The economic as well as disabling complications combined with have a serious and deleterious impact on our population if we do not make a concerted effort to stem this "tsunami." It has been estimated at 25% of obese children have impaired glucose tolerance (Sinha et al. NEJM, 2002; 346). In the state of Texas 21.1% of Texas children are obese. Therefore if we calculate this correctly, 5.5% of all Texas children are at risk for developing type 2 diabetes. The moral of the story: one in three U.S. children born in the year 2000 will become diabetic in their lifetime, unless we begin to encourage them to start eating less and exercising more. For young Black and Hispanic children, nearly half are likely to develop the disease.
If CDC predictions are accurate, 40-50 million U.S. residents could have diabetes by the year 2050. Regular physical activity is imperative. Mandatory physical education in the schools is a priority. With a school program of physical activity of 30 minutes/day, it has been shown to decrease obesity by 5%. A 60-minute/day program will help decrease obesity by 10%. By walking, doing housework, jogging, or engaging in any physical activity 30 minutes/day, one can lose 5-7% bodyweight or 15 pounds. This can help to reduce type 2 diabetes by as much as 58%.
The physical impact is multi-systemic. Co-morbidities due to early type 2 diabetes such as heart disease, early kidney disease, stoke, hypertension, skeletal deformities genu valgum, stress fractures, Charcot arthropathy, increase incidence of cancer, staetohepatitis (fatty liver), and others will result in a society of young disabled individuals. We can't afford to see this occur on our watch.
Diabetes will have a detrimental impact on our children's health. A recent review of mortality and survival from type 2 diabetes revealed a reduction of life expectancy in a child who developed this disease before age 15 of up to 27 years. If the disease was developed between age 15 and 19, the reduction in life expectancy was 23 years. If nothing is done to stop this epidemic of obesity, many children of this generation are unlikely to live as long as their parents.
It has been shown that 43% of adolescents watch more than two hours of TV a day. Combined with school as well as home computer screen time, and with videos and games, that figure is more likely to be much greater. We have to set an example to our children and to our society that daily exercise and proper nutrition selection are the right things to do. Otherwise, we all will suffer.
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|Title Annotation:||American Medical Athletic Association|
|Date:||Mar 22, 2006|
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