Although the dangers of dehydration and heat illness among children who are active in the heat have been documented, until recently no one knew the incidence of these conditions. The results of a study we conducted at the University of Connecticut reported a surprisingly high prevalence with two thirds of children being significantly dehydrated before practice. In addition, during the 4- to 6-hour practice, some of these children were unable to recover a normal hydration status even though water was available. Being dehydrated not only impacts the way children feel and perform but also can jeopardize their health and safety by putting them at an increased risk for heat illness.
Active children are more susceptible to dehydration than adults when exposed to hot weather (1). Although the reasons why children are at a greater risk for dehydration are likely behavioral, there are physiological factors that contribute to young athletes heating up more quickly than adults.
When active, children actually produce more metabolic heat per pound of body weight than adults (1). Additionally, young athletes have a lower sweating capacity, which reduces their ability to lose heat through sweat evaporation (1). Less developed sweat mechanisms ultimately result in a cooling disadvantage for young athletes and can cause active children to be more likely to suffer from headaches, dry mouth, dizziness, cramps, and thirst, which are key symptoms of dehydration.
Like adults, children frequently lack the physiological drive to drink enough water to replenish fluid loss during exercise (2). The lack of a drive to drink, combined with social and environmental distractions, make it difficult for young athletes to maintain proper hydration during activity. Not surprisingly, fluid breaks often tend to be more of a social outlet than a time for drinking. It is important to note that children who may be dehydrated are more likely to experience more serious heat-related illnesses, such as heat exhaustion or heat stroke.
Now let's take a look at what we've learned in the past two summers. In July 2003, our research team tested the hydration status of 58 male and female "tweens" (average age 12 to 13 years old, with a range of 8 to 15 years old) at two Pennsylvania soccer camps. Each day, during two 4-day soccer camps, we measured their hydration status using urine specific gravity, urine color, and thirst before and after four to six hours of practice. The average temperature was 82°F, with an average relative humidity of 50%. During activity, kids were provided with fluid coolers (within 25 meters) and frequent rest breaks, and were encouraged by coaches to drink.
The results showed that two thirds of soccer camp study participants were at least significantly dehydrated (urine specific gravity (USG) greater than 1.025) before they started four to six hours of activity in the heat. Of those, an average of 29% were seriously dehydrated (USG of 1.030 or greater) over the four days of camp. After activity, 57% of kids were still significantly dehydrated (3). Terms regarding degrees of dehydration were adapted from the National Athletic Trainer's Association Position Statement: Fluid Replacement for Athletes. Additionally, none of the kids who were significantly dehydrated before practice were able to regain healthy hydration status during the practice. These results underscore the importance of young athletes drinking on a schedule before, during, and after practice and games.
Even with their reduced sweating capacity, children lose more fluid than one might expect. Research shows that children the age of those in our study can lose up to a quart of sweat during two hours of activity on a hot day (4, 5).
In 2004, we expanded our research to not only look at the incidence of dehydration, but also at young athletes' attitudes toward the importance of hydration. In addition to looking at male and female tween soccer players, we increased the research population to include youth and teen male football players. Whereas the young athletes' incidence of dehydration was similar to or higher than the levels reported in past studies, we discovered some very interesting findings about the tween and teen athletes' hydration attitudes and how these attitudes impacted their behavior.
To learn more about the results of the 2004 study, look for these abstracts in the June 2005 supplement of ACSM's Medicine & Science in Sports & Exercise® and NATA's Journal of Athletic Training:
- Incidence and Degree of Dehydration and Attitudes Regarding Hydration In Adolescents At Summer Football Camp, lead author: Douglas J. Casa, Ph.D., ATC, FACSM
- Incidence and Degree of Dehydration and Attitudes Regarding Hydration In Children Participating in Summer Football Camps, lead author: Susan W. Yeargin, M.S., ATC
- Attitudes Towards Hydration and Incidence of Dehydration in Youths At Summer Soccer Camp, lead author: Nora R. Decher
- Thirst is Not a Valid Indicator of Hydration Status in Youth Athletes, lead author: Susan W. Yeargin, M.S., ATC.
The good news is, unlike many sports injuries, dehydration can easily be prevented. Following are some practical tips for parents, coaches, and athletic trainers to practice for prevention.
Drink Enough Fluids, On a Schedule
The key to prevention is to have young athletes drink enough of the right kinds of fluids, on a schedule, to replenish the fluid and electrolytes they lose through sweat. Drinking before, during, and after activity ensures children consume enough fluids to stay hydrated without overdrinking.
Weighing young athletes before and after activity is a simple way to ensure that fluids are fully replenished. If the child shows a weight loss, try gradually increasing fluid intake during practice and following the recommended guidelines shown in the Table to ensure that the child properly replaces fluids lost through sweat. The National Athletic Trainers' Association (NATA) and the American Academy of Pediatrics (AAP) recommend that active children follow these guidelines for drinking (6, 7).
Drink the Right Kinds of Fluids
Children's ability to drink enough, and thus prevent dehydration, may not only depend upon frequency of fluid breaks and coach encouragement, but also upon what's in the cooler. Research shows that kids drank 90% more sports drink than water when offered plain water, flavored water, and a sports drink (8). That's because the flavor and sodium in sports drinks encourage kids to drink more when active. Additionally, a scientifically formulated sports drink, like Gatorade, offers other benefits for active kids including the following:
- Replaces electrolytes that children lose through sweat (5)
- Helps to maintain the right balance of fluids in the body (2)
- Contains flavor to encourage drinking (1)
- Provides energy to refuel during activity.
Individual drinking containers also encourage drinking because parents can fill them with their child's favorite beverage. We suggest that parents and athletic professionals mark squeeze bottles with indicators of how much children should drink on each activity break.
Adjust Hydration Habits for the Weather
The heat index is another useful tool for parents, athletic trainers, and coaches to determine when to take special hydration precautions. The Figure recommends adequate fluid and activity breaks for young athletes according to the heat index (a combination of the temperature and relative humidity) (9).
Know the Warning Signs
Although preventing dehydration is the goal, it's also important to recognize when dehydration and heat illness strike children. Anyone who is responsible for children's health and safety on the field, including parents, athletic trainers, and coaches, should be able to identify these symptoms of dehydration (10, 11):
- muscle cramps.
Although thirst was formerly included in the list of common dehydration warning signs, 2004 youth hydration research suggests that thirst is not a good indicator of hydration status.
Defeat the Heat is a public safety campaign designed to educate parents and coaches about the dangers of dehydration and to provide tips for prevention. As a part of this mission, Defeat the Heat commissioned the youth hydration research we conducted to help quantify the scope of dehydration among youth athletes and to find solutions for decreasing their risk of suffering from dehydration and other heat-related illnesses. Defeat the Heat is a partnership between the National Athletic Trainers' Association and the Gatorade Sports Science Institute.
Condensed Version and Bottom Line
Approximately two thirds of young athletes are significantly dehydrated before practice. Dehydration not only impacts the way kids feel and perform, but it also can jeopardize their health and safety by putting them at an increased risk for heat illness. Parents, coaches, and athletic trainers need to be able to identify the common symptoms of dehydration: headache, dizziness, weakness, irritability, fatigue, nausea, and muscle cramps. Ensuring young athletes have plenty to drink before, during, and after physical activity is the best way to prevent dehydration.
1. Bar-Or, O. Temperature regulation during exercise in children and adolescents. Perspectives in Exercise and Sports Medicine, II. Youth, Exercise and Sport
. Gisolfi, C., and D.R. Lamb (Editors), Indianapolis: Benchmark Press, 1989, pp. 335-367.
2. Rivera-Brown, A., et al. Drink composition, voluntary drinking and fluid balance in exercising, trained, heat-acclimatized boys. Journal of Applied Physiology
3. Walker, S.M., D.J. Casa, M. Levreault, et al. Children participating in summer soccer camps are chronically dehydrated. Medicine & Science in Sports & Exercise®
4. Juliano, S., et al. Evaluation of the self-selected fluid intake practices by junior athletes during a simulated duathlon event. International Journal of Sport Nutrition & Metabolism
5. Meyer, F., et al. Sweat electrolyte loss during exercise in the heat: effects of gender & maturation. Medicine & Science in Sports & Exercise®
6. Casa, D.J., L.E. Armstrong, S. K. Hillman, et al. National Athletic Trainer's Association Position Statement: Fluid Replacement
for Athletes. Journal of Athletic Training
7.Adapted from the American Academy of Pediatrics Position Statement. Pediatrics
8. Passe, D.H., M. Horn, and R. Murray. Palatability and voluntary intake of sports beverages, diluted fruit juice, and water during exercise. Medicine & Science in Sports & Exercise®
9. Kulka, J., and W.L. Kenney. Heat balance limits in football uniforms: how different uniform ensembles alter the equation. Physician Sports Medicine
10. Epstein, Y. Exertional heatstroke: lessons we tend to forget. American Journal of Sports Medicine
11. Watts, S. Prevention
and treatment of dehydration
in athletes. American Journal of Sports Medicine
12. Casa, D.J., J. Almquist, S. Anderson, et al. Inter-Association Task Force on Exertional Heat Illness Consensus Statement. NATA News
24-29, June 2003.