Course:KIN366/ConceptLibrary/SportDehydration

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Movement Experiences for Children
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KIN 366
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Instructor: Dr. Shannon S.D. Bredin
Email: shannon.bredin@ubc.ca
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What is Sport Dehydration?

Dehydration can happen when children do not have adequate amount of fluids in their body (Dehydration in children, 2014). A loss in fluids could potentially cause electrolyte loss, such as sodium, which can happen in sports, with loss of fluid when an individual sweats (Dehydration in children, 2014).

How does it happen?

It is known that body fluid balance influences performance in sport and maintenance of health, which includes body electrolyte concentration, absorption, and body water content. (Meyer, Volterman, Timmons, & Boguslaw, 2012). With regard to body electrolyte balance, the amount of sweat you perspire is dependent on exercise intensity, duration of activity, ambient temperature, and humidity conditions (Rowland, 2011).

Water Loss

The measure of exercise-induced fluid losses is largely determined by sweat volume and composition. When assessing someone for dehydration, you want to know approximately the individual’s sweating characteristics as they can range from child to child as well as the environment (Meyer, Volterman, Timmons, & Boguslaw, 2012).

Electrolyte Loss

The major electrolytes lost in sweat are chloride and sodium and to a lesser degree potassium, calcium, and magnesium (Meyer, Volterman, Timmons, & Boguslaw, 2012).

Who is at risk and what are the risks?

Children put their body fluid balance at risk by training hard and/or under humid environmental conditions. (Meyer, Volterman, Timmons, & Boguslaw, 2012).

Children who show more than one of these symptoms are likely dehydrated and could be increased following exercise:

  • Dry mouth
  • Very sleepy
  • Restless, tired or fussy
  • Crying without any tears or sunken eyes
  • Urinating little or none, or having a urine colour of dark yellow
  • Cold, pale feet and hands

(Dehydration in children, 2014).

The risks of dehydration include cognitive function being impaired, lower level of concentration, decreased physical performance, fatigue, headaches, emotions of anger, constipation, and/or developing a urinary tract infection (Gibson-Moore, 2013).

What barriers prevent adequate fluid intake for children?

In school, most children do not drink water because it is not believed to be ‘cool’ by their classmates and peers (Gibson-Moore, 2013). In addition, barriers could also be due to the fact that increased water fountain/bathroom trips may be troublesome and disturb the learning of other classmates (Gibson-Moore, 2013). As well, children aren’t taught about the importance of hydration and may actually forget to drink because they were preoccupied (Gibson-Moore, 2013).

Physiological Responses to Dehydration

  • Decreased gastric emptying thereby preventing the rehydration rate
  • Increased likelihood of gastrointestinal irritation, which may cause the body to feel bloated and experience nausea
  • Vasopressin and angiotensin plasma levels rise in order to sustain sodium levels and decrease creation of urine
  • Splanchinic and renal blood flow declines as another way to maintain body fluids
  • Increased heart rate, to keep up with the stroke volume decrease in an attempt to sustain cardiac output
  • Decreased cardiac output which means that the heart rate cannot keep up with the drop in stroke volume and so cardiac output decreases
  • Declined sweat rate and blood flow in an attempt to maintain body fluids

(Murray, 1992).

Exercising in the Heat

The stress of heat exposure and exercise together places adverse challenges on the body (Murray, 1992).

When the body warms up to a specific temperature, many sweat glands in the skin are triggered to create sweat (Murray, 1992). Meanwhile the skin blood flow also increases by reacting to rising local skin temperature (Murray, 1992). Ultimately, the decrease in plasma volume and rise in plasma osmolarity signal the body that the fluid volume is decreasing and becoming alarmingly low (Murray, 1992). Therefore, the rise in skin blood volume and sweating display a fluid “loss” from the central blood volume (Murray, 1992).

Children are at a higher risk for dehydration when they exercise in the heat compared to adults because children have a larger surface area to body mass (Bar-David, Urkin, & Kozminsky, 2005).

Sweating Rates of Adults and Children

Children have smaller sweat losses during exercise than adults, and there is evidence that the rate of sweating increases with age and maturation of the human body (Meyer, Volterman, Timmons, & Boguslaw, 2012).

The water lost by a male adult while performing an intense physical workout is usually 0.5-2.0L/h, and can be even higher in the heat (Rowland, 2011). Sweating in boys reaches similar adult sweating levels by the time they hit puberty. Evidence as to why the prepubertal boys do not sweat as much as the adult males is due to the shortage of androgenic hormonal stimulation (Rowland, 2011). As well, it is recognized that adult men have more sweat responses than compared to adult women, and it is found the sweating rates of adult women are similar to premenarcheal girls (Rowland, 2011).

Since the sweating rates are determined based on differences in body mass, it was discovered that children and adults have complementary water losses during exercise after considerations for variations in weight (Rowland, 2011).

How much and what should children drink?

The rate of sweating varies from individual to individual so it would be hard to determine a specific amount they should be drinking (Rowland, 2011).

However, evidence suggests that if a child ingests liquids through ad libitum drinking, that is sufficient to avoid dehydration and the ad libitum guidelines can be utilized conservatively (Rowland, 2011). For instance, the approved fluid intake while exercising is 13mL/kg for every hour of activity. For example a 27kg child, it means they should be having 90 mL every 15 minutes or 360mL per hour (Rowland, 2011). A general guideline is to have 6-8 glasses per day (Gibson-Moore, 2013). The fluid that children drink should be according their preference and what tastes best to them because it is most important to ensure they receive the required volume of fluids rather than what is in the fluid (Rowland, 2011).

Since children aren’t as driven to regulate their appropriate fluid intake behaviour, the jobs of parents, guardians, and coaches are important to make sure the child athletes are properly hydrated before, during, and after exercise (Rowland, 2011).

However, it is noted that children should avoid juices and carbonated beverages (Rowland, 2011). The recommended beverage is water, followed with milk that they should be consuming regularly (Gibson-Moore, 2013). Fruit juices should be consumed in moderation and can be thinned out with water as it is acidic and sugary and could lead to tooth decay or tooth erosion if consumed in excess (Gibson-Moore, 2013). Smoothies can also be beneficial but only once per day and be taken with meals to also assist in maintaining healthy teeth (Gibson-Moore, 2013). The high acidity and sugary drinks should both be consumed at meals and preferably through a straw can decrease the surface exposure to the teeth (Gibson-Moore, 2013). Lastly, low calorie soft drinks, soft drinks with sugar, tea, and coffee should only be consumed occasionally in a child’s diet (Gibson-Moore, 2013). If they desire to drink coffee or tea, it should be decaffeinated and without any extra sugar (Gibson-Moore, 2013).

As well, children should be having fluids after their exercise. The exact amount can be determined from the difference of the weights pre and post exercise. For each 0.5 kg lost the child should be consuming 480mL of fluids (Rowland, 2011). However, if the weights are not available, for every hour of exercise, the child should consume 4mL/kg beyond their regular drinking amount (Rowland, 2011).


Please Note: These strategies are applicable to the bulk of active children; some of them may need more fluids and may need to talk to a physician about an individualized approach to determine how much fluid he or she should be consuming (Rowland, 2011).

Prevention

Tips for avoiding dehydration in children 4-13 years old:

  1. Drink 6-8 glasses of fluid per day, for younger children one drink would be 150mL serving and older children would be equal a 250-300 mL serving (Gibson-Moore, 2013).
  2. Prior to exercising, going to school, a game, or a workout, make sure they have a drink, preferably water (Gibson-Moore, 2013).
  3. Guardians, parents, and coaches should offer fluids to children often (Gibson-Moore, 2013).
  4. Assure that healthy drinks are readily available to the child (Gibson-Moore, 2013).
  5. Add a water bottle in their school lunch, gym bag, backpack or when the child is going on school outings (Gibson-Moore, 2013).
  6. Children who are smaller are at a higher risk for heat exhaustion and should be drinking 3-6 ounces of fluids every 15-20 minutes while exercising (Taylor & Francis, 2002).

References

Bar-David, Y., Urkin, J., & Kozminsky, E. (2005). The effect of voluntary dehydration on cognitive functions of elementary school children. Acta Poediatrica, 94, 1667-1673. doi: 10.1080/08035250500254670

Dehydration in children. (2014). In CareNotes. Truven Health Analytics Inc. Retrieved from http://go.galegroup.com.ezproxy.library.ubc.ca/ps/i.do?id=GALE%7CA385798299&v=2.1&u=ubcolumbia&it=r&p=HRCA&sw=w&asid=3fa9f418f9ca504cbd4c2bbf4470e439

Gibson-Moore, H. (2013) Improving hydration in children: A sensible guide. Nutrition Bulletin, 38, 236-242. doi: 10.1111/nbu.12028

Murray, R. (1992). Nutrition for the marathon and other endurance sports: Environmental stress and dehydration. Medicine & Science in Sports & Exercise, 24, 319-323. doi:10.1249/00005768-199209001-00003

Meyer, F., Volterman, K. A., Timmons, B. W., & Boguslaw, W. (2012). Fluid Balance and Dehydration in the Youth Athlete: Assessment Consideration and Effects on Health and Performance. American Journal of Lifestyle Medicine, 6, 489-501. doi:10.1177/1559827612444525

Rowland, T., (2011). Fluid Replacement Requirements for Child Athletes. Sports Medicine Journal, 41, 279-288. doi:10.2165/11584320-000000000-00000

Taylor & Francis (2002). 10 Essentials for Avoiding Dehydration. Strategies: A Journal for Physical and Sport Educators, 16, 18-18, doi:10.1080/08924562.2002.10590988