Posts Tagged ‘dehydration’

Exercise Associated Muscle Cramps

Monday, March 6th, 2017

Posted March 6, 2017

By Michelle Snow, MA, AT, CSCS

Muscle cramps are often associated with heat and dehydration. A 2003 study looked at the number of heat related illnesses during a football season. Seventy-three percent of these illnesses were related to muscle cramping.1  Dehydration has long been blamed as the cause of exercise associated muscle cramps (EAMC). The most common theory places blame on salty sweat removing electrolytes from the body.

However, if EAMCs are heat and dehydration related, why do people experience cramping during cold weather events or while swimming in cold water? And, why does stretching almost immediately relieve the EAMC?

Unfortunately, to date, very little evidence and research has found a cause for EAMC. Two theories have been developed to help explain what may contribute to cramping, the dehydration and electrolyte imbalance theory and the altered neuromuscular control theory.

Initially, it was believed fluid and electrolyte disturbances may cause EAMC. This theory hypothesized that sweating caused a loss of fluid and electrolytes. This would lead to contraction of the interstitial space and a loss of interstitial volume. The increase in surrounding ionic concentrations and mechanical deformation of the nerve endings leads to a hyper-excitable motor nerve and a spontaneous contraction.

The theory was based on observation that athletes who experienced EAMC would often have significant fluid and electrolyte losses at the time of the cramp.4 However, it has been shown that losses in fluids and electrolytes, plasma, blood volume and body weight are similar in individuals who experience EAMC and those who do not experience cramping. Even when given a sports drink that reflected individual fluid losses, approximately seventy percent of participants still experienced EAMC.2

Due to these discrepancies, the second theory regarding a neuromuscular etiology has the strongest support from current research. This theory hypothesizes that neuromuscular fatigue alters the reflex control mechanisms of both the muscle spindle and golgi tendon organ, eliciting muscle cramping.4

The muscle spindle responds to length changes in the muscle. As length increases, the muscle spindle increases impulses to the agonist muscle to contract and decreases impulses to the antagonist muscle so it relaxes. The golgi tendon responds to length changes in the tendon and causes the agonist muscle to relax. Both work together to protect the muscle from over stretching. However, with fatigue, it has been noted that the muscle spindle activity increases while the golgi tendon activity decreases.2 This may explain why muscle cramps occur later in activity once the muscle has fatigued.

In most studies, fatigue has been the most common contributing factor to muscle cramping. This may be caused by an increase in exercise intensity and/or duration. It has also been found that those who have a history of EAMC are more likely to cramp again during other bouts of exercise. Current injury or previous history of injury may also play a role in EAMC. And, it has been found that male athletes are more likely to cramp than female athletes due to the greater proportion of fast-twitch fibers4.

The most effective treatment for acute fatigue-induced muscle cramps is static stretching of the affected muscle. It is thought that static stretching activates the golgi tendon organ by increasing tension in the tendon, causing increased afferent reflex inhibition.4  While the old method of using pickle juice may not change the blood plasma concentrations of electrolytes, it has been found that the acetic acid in pickle juice may trigger a reflex that increases neurotransmitter inhibition to cramping muscles.3 This has been found to effectively shorten the duration of EAMC.

However, it may not be an effective treatment for athletes who develop stomach duress or acid reflux after consumption. Even though there is little evidence to support the dehydration-electrolyte theory, it is still recommended that athletes remain hydrated to prevent heat illness. It is important to continue to recommend athletes to consume enough fluid so that not more than two percent of body weight loss occurs due to perspiration.

Other treatments have been recommended, however, little research has been completed to determine how effective they may be. Plyometric exercises and eccentric exercise may be incorporated for athletes who chronically experience muscle cramps. One study looked at strengthening the gluteus medius to help an athlete who struggled with hamstring muscle cramping. With the agonistic relationship of the hamstring and the gluteus medius, it was proposed that the weak glut might increase the amount of work the hamstring needed to do,  fatiguing the hamstring more quickly. The athlete targeted in this study was able to complete 3 triathlons without EAMC following 3 weeks of the targeted strengthening.4

Further research is needed to explain what causes exercise associated muscle cramps. Fatigue plays a significant role in muscle cramping. However, it does not explain how some athletes experience cramps, while others do not. The most effective treatment is static stretching of the affected muscle.

Resources

1. Cooper, E. R., Ferrara, M. S., Broglio, S. P. (2006). Exertional Heat Illness and Environmental Conditions during a Single Football Season in the Southeast. Journal of Athletic Training, vol. 41, 332-336.

2. Miller, Kevin. The Neurological Evidence for Muscle Cramping. NATA Symposium, June 2011, New Orleans Convention Center, New Orleans, LA. Conference Presentation.

3. Miller, K. C., Mack, G. W., Knight, K. L., Hopkins, J. T., Draper, D. O., Fields, P. J., Hunter, I. (2010). Reflex Inhibition of Electrically Induced Muscle Cramps in Hypohydrated Humans. Medicine and Science in Sports and Exercise, vol. 42, no. 5, 953-961.

4. Nelson, N. L., Churilla, J. R. (2016). A Narrative Review of Exercise-Associated Muscle Cramps: Factors that Contribute to Neuromuscular Fatigue and Management Implications. Muscle and Nerve, vol. 54, no. 2, 177-185.

 

Save

Save

Save

Sodium’s Role in the Hydration Practices of an Active and Healthy Population

Thursday, March 31st, 2016

Posted March 31, 2016

Mike McKenney
MS, ATC

By Mike McKenney, MS, ATC

In a previous blog post, I briefly mentioned sodium ingestion plays a significant role in the application of hydration strategies. This is a topic often met with some confusion as there are many different recommendations available to healthcare providers. These recommendations can have a direct effect on the fluid balance of an athlete, such as those from the CDC1 and the FDA.2 With that said, this post is not intended to refute the CDC and FDA recommendations, or downplay potential health risks of excessive sodium ingestion, but rather provide a more refined context on the role sodium plays in the hydration practices of an active and healthy population.

Sodium should not be actively avoided by athletes. It is the primary electrolyte that helps drive thirst and maintain appropriate fluid balance in the extracellular fluid space.3 Repetitive bouts of exercise with insufficient sodium replacement can lead to decreases in plasma volume due to an athlete's inability to retain water. This further reduces an athlete's performance as well as the ability to tolerate exercise in hot environments.4 Exercise-associated muscle cramping (EAMC) is a condition commonly assumed to be the result of decreased sodium levels. However, recent investigations indicate there is no reliable, scientific link between EAMC and sodium loss.5 But if athletes should be ingesting sodium, how much is appropriate to ingest?

According to the CDC1,consuming excessive amounts of sodium will have negative effects on the human body to include increased risk of heart disease and high blood pressure. However, similar to general hydration recommendations, sodium recommendations are made to be broadly applied to the general population. The FDA2 agrees with the aforementioned statement, but adds a caveat to their recommendation (added emphasis is mine): "Sodium is an essential nutrient and is needed by the body in relatively small amounts (provided that substantial sweating does not occur)." As Athletic Trainers (ATs), we often find ourselves in settings where substantial sweating is not only a normal occurrence for our patients, but a daily one, which places them in a population who have different needs.

It should not be assumed that a typical diet will be sufficient to replace sodium in athletes. Sweat sodium concentrations and sweat rates can vary widely6, resulting in the need for individual replacement plans. In situations where fluid loss is great, sodium losses can far exceed standard nutritional recommendations. Currently, it is recommended adults 14 and older should consume about 2.3g of sodium per day.7 However, it has been demonstrated athletes can easily exceed this recommendation in a single training session or game:

- Ice-hockey players can lose 5.7g in a single game8

- Soccer players can lose 2.4g in a single training session9

- Football players can lose up to 17.5g following a two-a-day practice6

Likewise, due to large variations in sweat rate and sweat sodium concentrations, some athletes are perfectly fine with their diet alone. Knowing how much an athlete needs is necessary in order to make an appropriate recommendation, and this can be accomplished with minimally invasive sweat testing services offered by a number of companies. Additionally, replacement can be achieved with the sodium consumed as part of a meal, such as chicken noodle soup,10 or with a number of commercially available products. However, care needs to be taken to understand an athlete’s medical history prior to making any sodium supplementation recommendations in order to account for medical conditions where this practice is potentially contraindicated.

Resources

1. http://www.cdc.gov/salt/

2. http://www.fda.gov/Food/ResourcesForYou/Consumers/ucm315393.htm (Know Your Numbers)

3. Shirreffs S, Maughan R. Volume repletion after exercise-induced volume depletion in humans: replacement of water and sodium losses. Am J Physiol. 1998;274(5 pt2):F868-875.

4. Shirreffs SM, Sawka MN. Fluid and electrolyte needs for training, competition, and recovery. J Sports Sci. 2011;29(S1):S39-S46.

5. Murray D, Miller KC, Edwards JE. Does a reduction in serum sodium concentration or serum potassium concentration increase the prevalence of exercise-associated muscle cramps? J Sport Rehabil. 2015 [Epub ahead of print]. 

6. Fowkes-Godek S, Peduzzi C, Burkholder R, Condon S, Dorshimer G, Bartolozzi AR. Sweat rates, sweat sodium concentrations, and sodium losses in 3 groups of professional football players. J Athl Train. 2010;45(4):364-371.

7. http://health.gov/dietaryguidelines/2015/guidelines/

8. Godek, S.F., Godek, J.J., McCrossin, J., and Bartolozzi, A.R. 2006. Sweat and sodium losses in professional ice hockey players during a pre-season practice and a game. Med Sci Sports Exerc. 38: S218–S219.

9. Maughan R, Merson S, Broad N, Shirreffs S. Fluid and electrolyte intake and loss in elite soccer players during training. Int J Sport Nutr Exerc Metab. 2004;14(3):333-346

10. Ray ML, Bryan MW, Ruden TM, Baier SM, Sharp RL, King DS. Effect of sodium in a rehydration beverage when consumed as a fluid or meal. J Appl Physiol. 1998;85(4):1329–1336.

About the Author

Mike McKenney is an Athletic Trainer (AT) at Northeastern University in Boston, Massachusetts, where he is the Medical Coordinator for their Division I men’s ice hockey program.  Prior to Northeastern University, he served as an AT in multiple settings including secondary schools, Division I athletics and professional cycling; additionally, he worked as an AT who extends the services of a physician for a large orthopedic group.  He has also provided services for many organizations to include the Boston Marathon, USA Cycling and USA Volleyball.

McKenney is a hydration and electrolyte replacement consultant for the Atlanta Hawks of the NBA.  His professional interests include hydration, electrolyte replacement, thermoregulation in sport and postural restoration.  McKenney completed his athletic training education at Gustavus Adolphus College in Saint Peter, Minnesota and master’s degree at North Dakota State University in Fargo, North Dakota.  His graduate research was published in the February 2015 edition of the Journal of Athletic Training.

Water: The Elixir of Life

Wednesday, November 11th, 2015

Desi Rotenberg, MS, LAT, ATC

Dehydration is a normal process of life that arises when biological beings do not replenish their water sources.  Dehydration can compromise athletic performance as well as normal activities of daily living.  It can also increase the risk of exertional heat illness.  Semantics will tell us dehydration is the “act or process of becoming hypo-hydrated” (dictionary.com).  The key concept of hydration is our body must maintain a stable, homeostatic environment and cannot do so without the regular intake of water.

As an anatomy teacher at the high school level, one of the first presentations I give covers basic human needs.  The most important concept we discuss is water and replenishment.  Rather than just teaching the concepts, I make it a rule in the classroom that students will not bring any beverages to class other than water.  Furthermore, I encourage my students on a regular basis to bring a water bottle to school and refill it several times throughout the day.  It is recommended we drink eight, 8-ounce glasses per day.  Most of the high school students and athletes I have been around do not even reach half that number.

It amazes me that a basic human need can elude so many young individuals.  As Athletic Trainers, we ensure our athletes are well hydrated and know how much water to drink and when.  However, I believe we tend to overlook the non-athletes.

Working with 190 students at the public school level, I administered a survey that revealed only 70 of the 190 (36%) students carried a water bottle with them to school.  Of the other 120 students who did not carry a bottle with them, only 50 students stated they drank water regularly (more than twice) throughout the course of the school day.   The results of the survey showed nearly 36% of my students did not have a daily water-replenishment routine.

My tentative plan for intervention:

Every student will be required to bring a water bottle to my class.  Some of them will forget, but if I keep reminding them, eventually, persistence will beat resistance.  This is my attempt to help students overcome the long term negative symptoms of chronic dehydration.

Drinking water regularly can lead to better immune function, better cognitive and mental capacity, better memory, more energy and better digestion.  Globally, water is essential to survival because every cell in our body is made up of about 70-75% water.

Preventing the negative effects of dehydration is about education and creating a constant awareness.  We must continue to take our knowledge and help as many people as we can beyond our athletic teams, clinics, high schools and gyms.

Resources

NATA Position Statement: Fluid Replacement for Athletes

Dehydration Precautions in Winter Weather

Friday, November 15th, 2013

Frostbite and hypothermia are not the only health hazards associated with frigidly cold temperatures. People lose a great deal of water from the body in the winter due to respiratory fluid loss through breathing. The body is also working harder under the weight of extra clothing and sweat evaporates quickly in cold, dry air.

Dehydration can occur when athletes don’t take in enough water to compensate for the water lost during routine processes or exercise. Awareness, recognition and education are the ways to help prevent dehydration during cold weather training. The goal is to replace 100% of sweat and electrolytes lost during exercise outdoors. Read more about dehydration and performance and cold weather nutrition and hydration from Jeffrey A. Kline, ATC, NASM-PES.

During warmer weather we are very aware of water loss because of the sweating mechanism our body uses to keep cool, but it is harder to recognize when there is cold weather. Shifting temperatures and not having enough water can cause cramping and increases injuries.

Drinking water or sports drinks before, during and after sports is especially important for children and pre-teens because they have special fluid needs compared to adults, or even teenagers. A good way to monitor proper hydration is to examine urine output - the color should be nearly clear.

As a parent or coach, make sure you take precautions to prevent heat illnesses in children and that they follow recommended sports hydration guidelines. Review the Youth Sports Hydration Guidelines reviewed by Susan Yeargin, PhD, ATC, on www.Momsteam.com.

Written By:
Brittney Ryba
brittneyr@bocatc.org

Hydration and Nutritional Considerations in Cold Weather

Wednesday, October 17th, 2012

The leaves are changing colors and the temps are beginning to drop. In fluctuating temperatures, staying hydrated is still important. Water is an essential component for all processes the body completes each day. The human body is made up of 70% water; most of the water is found in and around tissues like skin and within the tiny individual cells that make up our body parts like organs. Dehydration can occur when we don’t take in enough water to compensate for the water lost during routine processes or exercise.  

Awareness, recognition and education are the ways to help prevent dehydration during cold weather training. The goal is to replace 100% of sweat and electrolytes lost during exercise outdoors. Read more about dehydration and performance and cold weather nutrition and hydration from Jeffrey A. Kline, ATC, NASM-PES.

During warmer weather we are very aware of water loss because of the sweating mechanism our body uses to keep cool, but it is harder to recognize when there is cold weather. Shifting temperatures and not having enough water can cause cramping and increases injuries. Read more about hydration and cramping at www.Livestrong.com.

Drinking water or sports drinks before, during and after sports is especially important for children and pre-teens because they have special fluid needs compared to adults, or even teenagers. As a parent or coach, make sure you take precautions to prevent heat illnesses in children and that they follow recommended sports hydration guidelines. Review the Youth Sports Hydration Guidelines reviewed by Susan Yeargin, PhD, ATC on www.Momsteam.com.

Written By: Brittney Ryba
brittneyr@bocatc.org