Water makes up 50-65% of total body weight and is essential for life. It performs many critical functions in the body like regulating temperature, aiding digestion, and transporting nutrients. The average adult loses 1,750-3,000 mL of water daily through the skin, lungs, urine, and feces. Proper hydration is important to prevent heat-related illnesses and impaired physical and mental performance. While most health experts recommend around 8 glasses of water per day, individual needs vary based on activity level and environmental conditions. Both overhydration and dehydration can be dangerous, so monitoring urine color is a good way to assess hydration status.
2. Water
2
50-65% of total body weight
Survive 6 weeks or longer without food
Survive only days without water
(approx. 6 days)
WATER IS ESSENTIAL!
3. Functions of Water
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Provide shape and structure to cells
Regulate body temperature
Aids in digestion and absorption
Transports nutrients and oxygen into cells
Eliminate waste products
INVOLVED IN VIRTUALLY EVERY BODY
FUNCTION
4. Water losses
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On average, adults lose approximately 1750 to 3000
mL of water daily
Insensible water losses from the skin and expirations
account for approximately ½ of the total water lost
Extreme environmental temperatures, high altitude,
low humidity, and strenuous exercise increase
insensible losses
Water evaporation from the skin is also increased by
prolonged exposure to heated or recirculated air such
as during long airplane flights
5. Water and Fluoride
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Water is a major source of fluoride
Fluoride - formation and maintenance of enamel
and resistance to tooth decay
Added to 70% of all municipal water supplies in US
Not removed by filters
6. Water losses
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Sensible water losses from urine and feces make
up the remaining water loss
Because the body needs to excrete a minimum of
500 mL of urine daily to rid itself of metabolic
wastes, the minimum daily total fluid output is
approximately 1500 mL
7. Water Intake
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35-55% consumed comes from tap/bottled water
49-63% comes from other beverages
19-25% comes from food
8. Water in Food
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Fruits and vegetables
- made up of 70-90% water
Meats
- made up of 50-70% water
Most beverages
- made up of more than 85% water
9. Foods with High water content
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Lettuce
Watermelon
Broccoli
Carrots
Grapes
Tomatoes
Oranges
10. Bottled vs. Tap Water
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Both are regulated by the FDA
25% of bottled water is actually tap water
“Enhanced” waters are more commercial than
nutritional
11. Plastic Bottles and BPA
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Certain types of plastics contain BPA (bisphenol A)
Softening compound that makes plastic flexible
Released when plastic is heated
Similar shape to estrogen
May be linked to increased risk :
- reproductive problems
- heart disease
- diabetes
- behavior changes
12. How much do we need?
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Men AI = 3.7 L per day (approx. 15 cups)
- 3 L coming from water and beverages
Women AI = 2.7 per day (approx. 11 cups)
- 2.2 L coming from water and beverages
8 glasses a day???
- most do not consume this amount
- no scientific evidence that increased intake increases
health
13. How do we know if we’re getting enough?
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Thirst – poor indicator of hydration status – may be
2-3% dehydrated before you feel it
Urine color – pale yellow – like lemonade
14. Fluids That Don’t Hydrate
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Fluids with >8% carbohydrates can increase
dehydration
- can also draw water in the stomach, causing
fullness and cramping
Alcoholic beverages are not hydrating
- diuretic
- *Beer is used after some marathons for CHO
In a sodium-depleted person, water is not hydrating
16. Estimating Fluid Needs During
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Exercise
Sweat rate
- Fluid loss per hour of exercise
- Sum of body weight loss plus fluid intake
Calculate sweat rate:
- Weigh yourself 1 hour before/after workout
- Subtract post-workout weight from pre-
- 1 pound lost = 16 oz
17. Inadequate Intake of Water
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Dehydration
Impaired mental function
Impaired motor control
Increased HR
Unresolved dehydration can lead to kidney failure
and even death
18. Consequences of Dehydration
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Dehydration:
- Loss of more than 2% of body weight (2-4 pounds)
during an event
- Impairs performance
- Can lead to heat exhaustion or heat stroke
19. Heat Exhaustion
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Caused by body H2O & Na due to
excessive loss of water through sweat
in hot weather
Symptoms:
- intense thirst - weakness
- paleness - dizziness
- nausea - fainting
- confusion
Remedy: fluids w/ electrolytes & rest in
a cool place
20. Heat Stroke
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Requires emergency Body temp. > 105° F
medical care - breakdown of
Characterized by: mechanisms that regulate
- hot, dry skin body temp.
- labored, rapid breathing
- rapid pulse AKA sunstroke
- nausea
- blurred vision Caused by prolonged
- irrational behavior exposure to environ. heat
- coma or strenuous activity
21. Signs of Dehydration
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Thirst
Lightheadedness or fatigue
Headache or inability to concentrate
Feeling cold or chills in hot weather
Collapse due to heat exhaustion or heat stroke
Producing small amounts of dark-colored urine
22. Hyponatremia and Athletes
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Hyponatremia
- Low blood sodium
- Life-threatening condition in marathon runners
- Caused by consuming large amounts of water
without sodium during an endurance event
- Causes difficulty breathing, bloating, confusion,
nausea, vomiting, swelling around brain
23. Water Intoxication
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Too much water – hyponatremia
– dilute constituents in blood
- causes imbalances of water
and electrolytes
– rare
Symptoms:
- confusion - headache
- vomiting - seizure
- coma - death
24. Water Intoxication
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Can lead to death
Jennifer Strange
“Hold your wee for a wii”
Drank 2 gallons of water
Died 6 hours later
Video
Radio station was held
accountable for her death