Water

Water essential essential 60% body weight: influenced by body composition 60% body weight: influenced by body composition – 75% of lean tissue is water – < 25% of fat is water Fluid between the cells (intercellular or interstitial) Fluid within the cell (intracellular)

Water carries nutrients and wastes carries nutrients and wastes maintains molecule structure maintains molecule structure involved in metabolism involved in metabolism solvent solvent lubricant lubricant aids in regulation of body temp aids in regulation of body temp blood volume blood volume

Water Intake thirst and satiety thirst and satiety – blood becomes concentrated – mouth becomes dry – hypothalamus initiates drinking – stomach and heart receptors indicate fullness fullness OK blood volume OK blood volume

Water Intake thirst lags behind the bodys needs thirst lags behind the bodys needs dehydration dehydration – water output exceeds water input

Water Sources water water fruits/vegetables = up to 90% water fruits/vegetables = up to 90% water meats and cheeses = 50% water meats and cheeses = 50% water generated during metabolism generated during metabolism – breakdown of C and H combine with O CO 2 and H 2 0 CO 2 and H 2 0

Water Losses 500 ml a day for urine 500 ml a day for urine any more is adjusted by the kidney to maintain balance any more is adjusted by the kidney to maintain balance water is also lost from water is also lost from – lungs – sweat – feces amount varies dependent on environment and physical condition amount varies dependent on environment and physical condition

Water Recommendations Adequate Intake Adequate Intake – men L/day – women L/day 2000 kcal/day – 2-3 L/day (7-11 cups) 2000 kcal/day – 2-3 L/day (7-11 cups) – drinking water, other beverages and food

Water Recommendations change depending on environment and physical condition change depending on environment and physical condition need to be replenished daily need to be replenished daily

Water soft water soft water – salt – easily dissolves contaminant minerals hard water hard water – calcium

Water blood volume blood volume – hormones and enzymes are key players in the retention or release of substances or water from the body

Electrolytes a mineral salt dissolves in water a mineral salt dissolves in water separates into ions separates into ions – positive (cation) and negative (anion) – electrolytes remains balanced remains balanced

Electrolytes attract water salt are dissolved in the water salt are dissolved in the water – moves fluids into cells and outside of cells (water follows the electrolytes) maintains water balance maintains water balance maintains acid-base balance maintains acid-base balance

Fluid Imbalance body can easily regulate body can easily regulate extreme situations require intervention extreme situations require intervention – heavy sweating – burns – severe and prolonged vomiting and diarrhea

Acid-Base Balance metabolism generates hydrogen ions (H+) metabolism generates hydrogen ions (H+) – acidic – must be neutralized blood buffers blood buffers respiration in the lungs respiration in the lungs excretion in the kidneys excretion in the kidneys