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Finish First Insider, Issue #50
March 23, 2009
Please enjoy another issue packed with evidence-based information about sports performance training and news about current events at Finish First Sports Performance. If you find value in this e-newsletter, please forward this message to your teammates, coaches, or other parents of hard working athletes.
Hydration and Heat: Current RecommendationsBy Coach J. Hoy, CSCS, USAW, Jump Stretch, Inc. Certified,
Elite Performance Scientist
This week I want to talk about two issues that are similar: hydration and exercise in a hot environment, and exercise associated hyponatremia (over-hydration with sodium deficiencies). I was recently approached by several parents with questions about fluid intake and exercise, and, additionally, were asking what I knew about sodium and exercise. (I think the sodium questions were specific to Gatorade). Also, there were several local marathon runners inquiring about my thoughts on sodium intake and hyponatremia.
Prior to these questions, I knew that sodium was an important electrolyte that needed to be replaced after exercise, and often during prolonged bouts of intense exercise or endurance activity. The majority of the athletes that I coach/train are wrestlers, soccer players, football players and ice hockey players, so most of my knowledge pertaining to sodium, hydration (pre-activity, during activity, and post activity), and heat was mostly associated with these sports (competition and preparation/practice).
I was much less familiar with the term hyponatremia and the prevalence of this condition in marathon runners, triathletes, and ultra-distance /endurance athletes.
Of the sports I coach, the one that poses the biggest challenge (regarding hydration and exercise) is wrestling, especially in wrestlers that are attempting to lose weight, yet maintain hydration status for NCAA or PIAA regulations, and still be able to perform optimally (conditioned appropriately)ó(and unfortunately, many of these athletes AND coaches still think that itís ok to put a plastic or rubber suit on to sweat out the extra weight--talk about increases in core temp!).
As a general rule, it has always been my recommendation (based on research that I did several years ago and discussions with Finish First Sports Nutrition advisor Heather Mangieri) that athletes should consume 4-6 ounces of fluid every 15 minutes of activity. This has been shown to allow for gastric emptying and intestinal absorption. Greater amounts of fluid intake result in excess fluid that is not absorbed for rehydration, which may lead to hyperhydration, or may present the need for the athlete to void via urination. I understand that this differs for each athlete, and according to the intensity of sport, plus the environmental conditions, but this has just been something I used as a general guideline. I typically never recommended a sports drink during activity, but only post activity, and that was mainly based on rehydration (first and foremost) and replacement of CHO, and had less to do with any understanding of sodium and exercise. So, Iíd have to say that, after looking more closely at this question, I was originally more familiar with hydration and heat, and less with the role of sodium.
So, I decided to take a closer look at research studies about sodium intake and exercise. After looking more closely at research about sodium, hydration, and exercise, it became apparent that discrepancies exist about recommendations for hydration in the heat.
While some research provides recommendations (5), contradictory research suggests that current guidelines on hydration and heat for athletes were based on studies conducted with no relevance to athletes or to extreme environmental conditions such as heat, or based on limited studies with poor research methods (2)(3). Additionally, it has been recommended that guidelines for hydration should be given by organizations that have no affiliation or influence, or relationship with the sports drink industry (3).
Research was found that recommends the consumption of a sodium containing beverage at concentrations 2-4 times greater than commercially available sports drinks, especially in warm training enviroments (6), another study reported that an electrolyte containing sports drink does not protect an athlete from hyponatremia (4), while another study suggests consuming a commercially available sports drink is necessary for complete rehydration and to prevent hyponatremia (8).
Interestingly, some research suggests that an athleteís bodyweight should be measured pre and post exercise to determine sweat loss and to more accurately prescribe a rehydration plan (8), while basic physiology shows that this may not be an entirely accurate method to determine sweat loss due to weight loss from utilization of additional metabolites during exercise. Additionally, it has been shown that recording weight changes pre and post activity can be useful in determining if a symptomatic athlete is suffering from dehydration or over-hydration (hyperhydration) following an event (7).
Research shows that to help regulate temperature during exercise in a hot environment, it is important to begin any physical activity in a euhydrated state to help prevent dehydration, combat the potential adverse effects of a hot, humid environment, and to help prevent exercise associated hyponatremia (1)(5).
More research is needed specific to athletes, sporting events, and specific environmental conditions to better form a guideline for hydration, sodium replacement, and exercise in heat. In the meantime, I have not changed my recommendations for hydration as a result of the inconclusive research that I found. However, I would like to point out that some research has shown that athletes participating in longer endurance activities may benefit from consuming a sodium/electrolyte sports drink--unfortunately this research was conducted via a relationship with a sports drink manufacturer so it is difficult to decipher if this relationship may have flawed the methods, results, or scientific model used to get to a specific conclusion.
1. Galloway SD. Dehydration, rehydration, and exercise in the heat: Rehydration strategies for athletic competition. Can J Appl Physiol. 1999;24(2):188-200.
2. Goulet E. Pre-exercise hyperhydration: Comments on the 2007 acsm position stand on exercise and fluid replacement. Journal of Exercise Physiology Online. 2008;11(2):64-74.
3. Noakes TD. Drinking guidelines for exercise: What evidence is there that athletes should drink ''as much as tolerable'', ''to replace the weight lost during exercise'' or ''ad libitum''? J Sports Sci. 2007;25(7):781-796.
4. Rosner MH, Kirven J. Exercise-associated hyponatremia. Clin J Am Soc Nephrol. 2007;2(1):151-161.
5. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American college of sports medicine position stand. exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377-390.
6. Sharp RL. Role of sodium in fluid homeostasis with exercise. J Am Coll Nutr. 2006;25(3):231S-239s.
7. Speedy DB, Rogers IR, Noakes TD, et al. Diagnosis and prevention of hyponatremia at an ultradistance triathlon. Clin J Sport Med. 2000;10(1):52-58.
8. Valentine V. The importance of salt in the athlete's diet. Curr Sports Med Rep. 2007;6(4):237-240.
Important!!! New Hours Effective March 30th, 2009Attention All:
Beginning March 30th, 2009, and continuing through April 24th, the world headquarters training facility will not open until 3pm, Monday through Friday.
There will be teams using the facility prior to 3pm on these days, so no one else will be permitted to use the facility during these times.
Again, beginning March 30th, 2009, regularly scheduled workouts will not begin until 3pm.
Normal hours will resume following the week of April 24th, and summer hours will begin mid-may. The new summer hours will be disclosed at a later date.
I apologize for any inconvenience and look forward to continuing to better serve your needs.
Scheduling for ALL WorkoutsEffective April 1, 2009, all athletes will need to be scheduled for ALL workouts.
By scheduling all workouts, we will be able to better plan to prevent overcrowding and allow for optimal training conditions.
If you have any questions, please call Jeremy (412-787-5070).
Motivational Quotes"Always look at what you have left.Never look at what you have lost."
-- Robert H. Schuller
"Minds are like parachutes - they only function when open."
"The greatest discovery of my generation is that human beings can alter their lives by altering their attitudes of mind."
"When you know what you want,and you want it badly enough,you'll find a way to get it."
Finish First Sports Performance CongratulationsCongrats to all the Finish First Sports Performance athletes (including former Finish First athletes like Seneca Valley coaches Denis Kirstein and John Dingle) that participated in the PIHL semi-final championships at Mellon Arena last week.
Best wishes to Seneca Valley and Montour High School in their championship games Monday night at Mellon!
Additional Congrats to the team Pittsburgh U14 and U16 Girls AAA Hockey teams in their Mid-Am District Championships. Keep up the great work and all the best in the upcoming national tournament!
WPIAL Wrestling Legends NightSaturday evening, April 4th, 2009, Chartiers Valley High School will host the 2nd Annual WPIAL Legends wrestling classic featuring some of the best WPIAL wrestlers ever assembled under one roof!!!
Finish First Sports Performance will be sponsoring a weight class and will be in attendance to cheer on our sports psychology advisor, Dr. Mark Marshall in his match.
Please join us for an evening of great wrestling and fun.
More information about the even can be found here.
Thank You for Your Support
Thanks again for subscribing to this free e-newsletter. I hope you enjoy reading it as much as I enjoy writing it. I look forward to your feedback as I continue to research to bring you the most current scientific training information available.
Should you have any specific article requests or questions, email me at firstname.lastname@example.org. Please visit www.finishfirstsports.com for detailed sports performance training information and programs offered exclusively by Finish First Sports Performance.
Yours In Training,
Coach Jeremy S. Hoy, CSCS, USAW, Jump Stretch, Inc. Certified,
For Finish First Insider backissues #1 - 29, click here
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