Dehydration These slides address the problems of dehydration and math exercises related to dehydration. This slide show is meant to be an activity for the Dark Poison

Dehydration Dehydration can be defined as when the loss of water and salts is more than is replenished. The average person loses about 2.5 liters of water every day. So to stay properly hydrated you must replenish this water in order to keep from being dehydrated.

Dangers of Dehydration Dehydration can lead to any of the following problems: Cramps Headaches Diarrhea Fever Vomiting Hallucinations Death In fact, dehydration is the leading cause in deaths of infants.

Water in the Body Water makes up approximately 60% of the male body mass, and 50% of the female body mass. Water makes up 75% of muscle mass, but only 25% of fat mass. So the lower a person’s body fat percent is, the higher their water percent will be.

Body Mass Water makes up 60% of a man’s body mass. How much water is in a man who weighs 215 lbs? Assume that the previous man has 24 lbs of fat and the water in his body due to fat and muscle is 100 lbs. Using the fact that fat is 25% weight by mass and muscle is 75% weight by mass, how much muscle mass does the man have? 215 lbs weight x (0.60 lbs water / 1 lb weight) = 129 lbs of water 24 lbs of fat x (0.25 lbs water / 1 lb fat) = 6 lbs of water from fat 100 lbs of water – 6 lbs of water from fat = 94 lbs water from muscle 94 lbs water from muscle x (1 lb muscle / 0.75 lbs of water) = 125 lbs muscle

Dangerous Dehydration There are three types of dehydration Mild – Less than 5% weight loss Moderate – 5-10% weight loss Severe – 10-15% weight loss Severe dehydration requires immediate medical attention and can lead to death.

Dehydration Problems Now we are going to do some math problems related to dehydration.

Diagnosing Dehydration Determine whether each of the following people are severely, moderately, or mildly dehydrated. (a) A woman who normally weighs 120 lbs and has lost 5 lbs (b) A woman who normally weighs 140 lbs and has lost 20 lbs (c) A man who normally weighs 190 lbs and has lost 15 lbs (a) (5 lbs / 120 lbs) * 100% = 4.2% Mildly Dehydrated (b) (20 lbs / 140 lbs) * 100% = 14.3% Severely Dehydrated (c) (15 lbs / 190 lbs) * 100% = 7.9% Moderately Dehydrated

Loss of Water If a woman weighs 125 lbs, how much water would she have to lose to become (a) mildly dehydrated (0-5%) (b) moderately dehydrated (5-10%) (c) severely dehydrated (10-15%) How many gallons would that be? (1 gal = 8.3370 lbs of water) 125 lbs x 0% = 0 lbs 125 lbs x 5% = 6 lbs 125 lbs x 10% = 12 lbs 125 lbs x 15% = 18 lbs (a) 0 – 6 lbs of water (b) 6 – 12 lbs of water (c) 12 – 18 lbs of water 0 lbs of water x (1 gal / 8.3370 lbs of water) = 0 gal 6 lbs of water x (1 gal / 8.3370 lbs of water) = 0.72 gal 12 lbs of water x (1 gal / 8.3370 lbs of water) = 1.44 gal 18 lbs of water x (1 gal / 8.3370 lbs of water) = 2.16 gal (a) 0 – 0.72 gal (b) 0.72 – 1.44 gal (c) 1.44 – 2.16 gal

How about you? Kids between 10-12 need about half their body weight in ounces of water to remain adequately hydrated. Use a scale to determine how much you weigh, and how many ounces of water you would need. Have each student determine how much they weigh then determine how many mL of water they need each day. When the students measure themselves they will find their weight in pounds. To convert that to mL of water follow this formula: (Weight of student) x ( 1 ounce of water / 2 lbs of weight) = ounces of water required by student For example, a student who weighs 100 lbs need 50 ounces of water.

Glasses of Water Every glass contains 8 fluid ounces. Calculate how many glasses of water you need each day based on the number of ounces you previously calculated. For students to calculate the number of glasses of water they need each day have them follow this formula: (Number of ounces required per day) x (1 glass of water / 8 ounces of water) = Number of glasses of water required per day For example with the student in the previous example who weigh 100 lbs. That student would need to drink 6.25 glasses of water each day.

Measuring Water Now measure out the water you calculated in the last step. Use different size measuring cups to add up to the amount of water you need each day. Does the amount you calculated seem like too much? Too little?