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ASEPnewsletter 

 

July 2007 Vol. 11 No. 7   
 
 Editor: Dr. Lonnie Lowery

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Editor's Corner
ASEP-Newsletter Technical Issue
Lowery, L.



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JEPonline      Ask the EP...
 
Dietary Fat Intake is not Associated with High Levels of Circulating Lipoproteins or Total Cholesterol (second on page)
Brahler, C., et al.

  This month: Temperature Regulation!
Mike, J.



PEPonline      Why join ASEP?  



Reflections of an Editor: Peer Review and Professionalism
Boone, T.



  View the new web page! You'll be glad you did!
The ASEP Board of Directors


         






Editor's Corner
Lonnie Lowery, PhD, MA, MS, RD, LD
ASEPnewsletter Editor, ASEP Board of Directors


ASEP-Newsletter Technical Issue

Ironically, after reviewing this Newsletter's progress last month, we experienced a technical issue with our mailing list while transferring to our new mass email software.

So, this month, as Editor, I am going to politely ask that anyone no longer wishing
to receive this Newsletter simply unsubscribe
. Of course, I would prefer that you
remain with us as ASEP "stays the course" in championing the rights of
Exercise Physiologists throughout the United States - and abroad. Indeed, invite a
friend to subscribe. Other professions benefit from a unified voice. So should we.



Your Inside Scoop on Tough Questions

Ask the Exercise Physiologist (EP) is intended for informational purposes only. It is
not to be taken as healthcare advice. Please do not submit questions of a personal nature (e.g., fitness programs and nutrition advice solicitation). Thanks.

QUESTION:  In general, how does temperature regulation work and what are some considerations governing fluid intake?  

The EP Answer
by Jonathan Mike, MS, CSCS,
NSCA-CPT

Studies have demonstrated that athletes experience a degree of voluntary dehydration, even in the presence of available fluids, that lowers blood volume and negatively affects performance. Given the tremendous amount of heat that must be dissipated during exercise through sweat evaporation, athletes must pursue strategies that will sustain the hydration state. Failure to do so will result in poor performance and may also lead to heat illness.

Temperature regulation represents the balance between heat produced or received (heat-in) and heat removed (heat-out). When the body's temperature regulation system is working correctly, heat-in and heat-out are in perfect balance, and body temperature is maintained. The two primary systems for dissipating, or losing, heat while at rest are (1) moving more blood to the skin to allow heat dissipation through radiation and (2) increasing the rate of sweat production. These two systems account for about 85 percent of the heat lost when a person is at rest, but during exercise virtually all heat loss occurs from the evaporation of sweat.

 

Working muscles demand more blood flow to deliver nutrients and to remove the metabolic by-products of burned fuel, but at the very same time there is a need to shift blood away from the muscles and toward the skin to increase the sweat rate. With low blood volume, one or both of these systems fail, with a resultant decrease in athletic performance.

 

Heavy exercise can produce heat that is 20 times greater than the heat produced at rest. Without an efficient means of removing this excess heat, body temperature will rise quickly. The upper limit for human survival is about 110 degrees Fahrenheit (43.3 degrees Celsius), or only 11.4 degrees Fahrenheit (or 6.3 degrees Celsius) higher than normal body temperature. With the potential for body temperature to rise at the rate of about 1 degree Fahrenheit every 5 minutes, it is conceivable that under-hydrated athletes could be at heatstroke risk only 57 minutes after the initiation of exercise.

 

Athletes working hard for 30 minutes would create 450 kilocalories of excess heat that need to be dissipated to maintain body temperature. Since 1 milliliter of sweat can dissipate approximately .5 calories, athletes would lose about 900 milliliters (almost 1 liter) of sweat. In 1 hour of high-intensity activity, approximately 1.8 liters of water would be lost. On sunny and hot days when the heat of the sun is added to the heat produced from muscular work, athletes would need to produce even more sweat to remove more heat. Sweat doesn't evaporate off the skin as easily when it is humid, so even more sweat must be produced in hot and humid weather. Well-trained athletes exercising in a hot and humid environment may lose more than 3 liters of fluid per hour.

 

No level of low body water is acceptable for achieving optimal athletic performance and endurance, so athletes should have a strategy for maintaining optimal body water during exercise. The problem is that athletes often rely on thirst as the marker of when to drink. Since the thirst sensation occurs only after a loss of 1 to 2 liters of body water, thirst is an inappropriate indicator of when to drink. Instead, the athlete should strategize on how to never get thirsty. Ideally, this strategy should involve helping athletes determine how much fluid is lost during typical bouts of physical activity and developing a fixed fluid-consumption schedule from that information (typically 3 to 8 ounces every 10 to 15 minutes of a sodium-containing 6 to 8 percent carbohydrate solution).



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Opportunities Related to Exercise Physiology
 
Sports Medicine Coordinator
At PeaceHealth Lower Columbia Region in Longview, Washington, we recognize the simple truth that organizations do not achieve outcomes - people do. By nurturing relationships with the people around us, we're able to achieve the best possible outcomes for our patients, their families and our staff of caring professionals. Our Lower Columbia Region includes St. John Medical Center, a 200-bed acute care and Level III Trauma Center community hospital, and PeaceHealth Medical Group, a multi-physician practice. Currently, our In-motion Clinic is seeking a Certified Athletic Trainer for our Sports Medicine Coordinator opening.
 
As the primary point of contact, provide services to the hospital, the community, and area high schools, and community college sports programs. This is a full-time position with variable hours so flexibility is essential. Requires a Bachelor's degree in exercise science, medical based program, or related discipline, 2+ years' related experience, and 1+ years' supervisory/management experience. Must have current NATA and BAC, and a MS and/or Physical Therapy degree is preferred. We offer a salary range of $43,000 to $65,000, and a comprehensive benefits package.
 
The Longview area is an ideal location for the outdoor enthusiast with mild seasons offering year round outdoor activities. Our mountains, lakes, rivers, and the Pacific Ocean provide opportunities for snow skiing, water skiing, hiking, biking, camping, hunting, and fishing. With a population of approximately 35,000, Longview offers a quality of life with a unique combination of elegant residential areas, country living and the urban amenities of Portland, Oregon, and Seattle, Washington.
 
To view a complete job description and to apply, please visit our Web site at
PeachHealth   Lower Columbia Region.
 
 PeaceHealth is an AA/Equal Opportunity Employer.

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