WATER

WATER Essential nutrient – NO calories Essential nutrient – NO calories Part of every cell Part of every cell muscle  75% muscle  75% bones  25% bones  25% teeth  10% teeth  10% fat tissue  20-33% fat tissue  20-33% Higher body fat = Less H2O Higher body fat = Less H2O Higher lean = Higher H2O Higher lean = Higher H2O

WATER COMPARTMENTS

WATER Do not store water Do not store water How long can we survive without water? How long can we survive without water? Water varies by: Water varies by: Age – caused by loss of extracellular fluid Age – caused by loss of extracellular fluid embryo = ~97% embryo = ~97% newborn = ~75% newborn = ~75% adult = ~60% adult = ~60% elderly = ~<60% (~50%) elderly = ~<60% (~50%) Gender- because of LBM relationship Gender- because of LBM relationship Men = 60% of body weight Men = 60% of body weight Women = 50% of body weight Women = 50% of body weight

WATER ESTIMATES

FUNCTIONS Building material – part of every cell Building material – part of every cell Medium for chemical reactions – chemicals (enzymes, hormones, coenzymes) dissolve and act on metabolites Medium for chemical reactions – chemicals (enzymes, hormones, coenzymes) dissolve and act on metabolites Hydolysis – digestion Hydolysis – digestion Transport medium – solvent for waste products Transport medium – solvent for waste products Lubricant – water filled sacs around joints Lubricant – water filled sacs around joints Shock absorber – around brain and spinal cord Shock absorber – around brain and spinal cord Temperature control – cools skin, excess heat from metabolic reactions Temperature control – cools skin, excess heat from metabolic reactions Blood volume Blood volume

FLUID BALANCE Fluid loss  Fluid loss  Concentration of electrolytes  Concentration of electrolytes  Water absorbed from saliva  Water absorbed from saliva  Dry mouth, thirst stimulated Dry mouth, thirst stimulated Children, elderly, athletes Children, elderly, athletes

WATER REGULATION

WATER LOSSES Normal 2-3 liters/day Normal 2-3 liters/day Urine = ml Urine = ml Skin = ml Skin = ml Lungs = 350 ml Lungs = 350 ml Feces = 150 ml Feces = 150 ml Insensible losses (skin, lungs, feces) Insensible losses (skin, lungs, feces) GI tract 8 liters/day secreted as digestive juices  reabsorbed in colon GI tract 8 liters/day secreted as digestive juices  reabsorbed in colon

WATER OUTPUT

LOSSES INCREASED Alcohol Alcohol Caffeine Caffeine Diuretics Diuretics

OUTPUT DEPENDS ON Total intake Total intake Metabolic disturbances Metabolic disturbances Altered dietary intake: protein, NaCl, CHO increase urine output for urea, ketones, and Na Altered dietary intake: protein, NaCl, CHO increase urine output for urea, ketones, and Na Output of 1 liter/day = concentrated urine  increased risk of stones in susceptible people Output of 1 liter/day = concentrated urine  increased risk of stones in susceptible people

WATER SOURCES Fluids = ml Fluids = ml Solid food = ml Solid food = ml Metabolic water = ml Metabolic water = ml Needs = losses Needs = losses Input and output normally in equilibrium Input and output normally in equilibrium Obligatory waste excretion – need at least 500 ml to excrete metabolic wastes Obligatory waste excretion – need at least 500 ml to excrete metabolic wastes

WATER INPUT

DEHYDRATION – LOW WATER LEVELS Physical causes: Physical causes: Vomiting Vomiting Diarrhea Diarrhea Blood loss Blood loss Fever Fever Weight loss Weight loss Work in high temperatures/hot climates Work in high temperatures/hot climates Strenuous physical exercise Strenuous physical exercise

SYMPTOMS Thirst – not always reliable Thirst – not always reliable Loss of appetite Loss of appetite Decreased blood volume Decreased blood volume Impaired physical performance Impaired physical performance Impaired temperature regulation Impaired temperature regulation Muscle spasms Muscle spasms General debilitation General debilitation

LAB TESTS TO DIAGNOSE Increased hematocrit Increased hematocrit Increased serum sodium Increased serum sodium Increased albumin Increased albumin Increased BUN Increased BUN

WATER LOSSES 3% of body weight  decreased physical performance 3% of body weight  decreased physical performance 4-5% body weight  impaired mental function 4-5% body weight  impaired mental function 10% of body weight  life threatening 10% of body weight  life threatening 20% body weight  fatal 20% body weight  fatal

DEHYDRATION CHART

REHYDRATION Drinking enough fluid? Drinking enough fluid? color of urine color of urine volume of urine volume of urine weight loss weight loss For every pound lost drink 2 cups of fluid For every pound lost drink 2 cups of fluid During exercise – 1 quart fluid for every 1000 cal spent During exercise – 1 quart fluid for every 1000 cal spent drink 8-10 ounces every min. of strenuous exercise – may sweat 3 times that much drink 8-10 ounces every min. of strenuous exercise – may sweat 3 times that much At risk for Na depletion if longer than 4 hour workout – athletes acclimate, sweat less salty as become more conditioned At risk for Na depletion if longer than 4 hour workout – athletes acclimate, sweat less salty as become more conditioned

WHAT TO DRINK ? Caffeine - increases urination ? Caffeine - increases urination ? Soft drinks - empty calories ? Soft drinks - empty calories ? Gatorade, Allsport, Powerade - little nutritional value ? Gatorade, Allsport, Powerade - little nutritional value ? Beer - ETOH dehydrating effect, increase urination ? Beer - ETOH dehydrating effect, increase urination ? Juice ? Juice Vit C and K Vit C and K ? Water ? Water ? Glucose polymers & CHO powders – can provide energy value with less sweetness ? Glucose polymers & CHO powders – can provide energy value with less sweetness ? Salt tablets – increase dehydration ? Salt tablets – increase dehydration

WATER INTOXICATION Kidneys are overwhelmed – can’t excrete fast enough Kidneys are overwhelmed – can’t excrete fast enough Caused by Caused by Greatly increased water intake Greatly increased water intake Increased secretion of antidiuretic hormone Increased secretion of antidiuretic hormone Acute weight gain Acute weight gain  Physical symptoms Headaches Headaches Blurred vision Blurred vision Cramps Cramps Eventually convulsions Eventually convulsions

LABORATORY SIGNS Decreased hematocrit Decreased hematocrit Decreased serum sodium Decreased serum sodium Decreased albumin Decreased albumin Decreased BUN Decreased BUN Excess water dilutes Na  decreases Na concentration in ECF  water enters cells and upsets balance Excess water dilutes Na  decreases Na concentration in ECF  water enters cells and upsets balance