August 25, 2014
By: Michelle Ripperger, PT, DPT
As the weather warms and students get back in to the swing of fall athletics, dehydration is a concern that should be addressed. Dehydration occurs when more water exits the human system than is taken in. Since nearly 75% of the human body’s weight is made up of water, it is important to maintain the appropriate balance of water to allow to the body systems to function correctly. Below is a chart that depicts the approximate daily required intake of water based on body weight (http://www.medicinenet.com/dehydration/article.htm).
Body weight Daily fluid requirements (approximate)
10 pounds 15 ounces
20 pounds 30 ounces
30 pounds 40 ounces
40 pounds 45 ounces
50 pounds 50 ounces
75 pounds 55 ounces
100 pounds 50 ounces
150 pounds 65 ounces
200 pounds 70 ounces
Additional intake of water is required if the amount of water exiting the system increases. Excessive water depletion can occur with sweating (due to exercise or fever), diarrhea, vomiting, or increased urine output. Increased water output also occurs in individuals with diabetes or skin burns. Hyperglycemia with diabetes causes increased sugar to enter the urine, water follows the sugar in to the urine. Frequent urination and increased thirst are common signs of diabetes. Individuals with skin burns are not able to regulate the amount of fluid lost at the area of the burn.
Initial symptoms of dehydration are thirst and decreased urine output. The urine is more concentrated and presents as a darker color. As the condition worsens additional symptoms can occur: dry mouth, decreased sweating, light-headedness, nausea, vomiting, weakness, and muscle cramps. If the condition persists long enough, confusion and organ failure will occur. Below is a table that shows the amount of fluid loss associated with the different severities of dehydration (http://emedicine.medscape.com/article/906999-clinical#a0217).
Severity Infants (weight < 10 kg) Children (weight >10 kg)
Mild dehydration 5% or 50 mL/kg 3% or 30 mL/kg
Moderate dehydration 10% or 100 mL/kg 6% or 60 mL/kg
Severe dehydration 15% or 150 mL/kg 9% or 90 mL/kg
Prevention is key to avoiding dehydration. It is important for individuals to control conditions which may lead to dehydration, such as diarrhea, vomiting, fever, and diabetes. It is also important to take in more clear liquids when excessive fluid loss occurs and to avoid activities outside in the heat of the day. If practices are scheduled during hot times of the day, more frequent rest breaks should be given and more fluids should be consumed. The elderly and very young children should be watched more closely in the heat because their body systems are less effective at regulating temperature.
http://www.medicinenet.com/dehydration/article.htm, Benjamin Wedro, MD, FACEP, FAAEM
http://emedicine.medscape.com/article/906999-overview, Lennox H Huang, MD, FAAP