Index

A

Absorption, intestinal, 11-18;

see also Intestinal absorption

Acclimation to heat

affecting fluid intake, 199-201

salt consumption in, 41

sweat sodium losses in, 178-184

Acidity of beverages

examples of, 211-212

and quenching of thirst, 209

Aging

and body fluid responses to heat exposure, 218-225

thirst and rehydration in, 164, 223

and total body water, 195-197

Aldosterone secretion, in potassium deficiency from training in heat 120

Altitude affecting food intake, 207-208

Angiotensin II

atrial natriuretic factor affecting, 220

as thirst stimulus, 162, 172

Antidiuretic hormone

and plasma volume in heat exposure, 218

release of

cellular energy levels affecting, 188

plasma osmolality affecting, 172-173

secretion affected by aging, 219

Apple juice, composition of, 29

Arginine vasopressin;

see Antidiuretic hormone

Armyade in diarrheal disease, 113-114



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FLUID REPLACEMENT AND HEAT STRESS Index A Absorption, intestinal, 11-18; see also Intestinal absorption Acclimation to heat affecting fluid intake, 199-201 salt consumption in, 41 sweat sodium losses in, 178-184 Acidity of beverages examples of, 211-212 and quenching of thirst, 209 Aging and body fluid responses to heat exposure, 218-225 thirst and rehydration in, 164, 223 and total body water, 195-197 Aldosterone secretion, in potassium deficiency from training in heat 120 Altitude affecting food intake, 207-208 Angiotensin II atrial natriuretic factor affecting, 220 as thirst stimulus, 162, 172 Antidiuretic hormone and plasma volume in heat exposure, 218 release of cellular energy levels affecting, 188 plasma osmolality affecting, 172-173 secretion affected by aging, 219 Apple juice, composition of, 29 Arginine vasopressin; see Antidiuretic hormone Armyade in diarrheal disease, 113-114

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FLUID REPLACEMENT AND HEAT STRESS ATP levels, thirst related to, 188 Atrial natriuretic factor, plasma level changes in aging, 219-220 B Barometric pressure, and fluid intake, 207-208 Beer intake, effects during marching in heat, 210 Beverage composition acidity and osmotic concentrations in, 211-212 affecting thirst-quenching properties, 208-211 examples of, 29 Bicarbonate affecting water and sodium absorption, 16 in Armyade, 113 Blood flow muscle, in potassium deficiency, 121-123 to skin dehydration affecting, 25-26, 92 in heat exposure, 217 splanchnic aging affecting, 225 in heat exposure, 218 Blood volume ratio to plasma volume, 195 Body Fuel450, composition of, 29 C Caffeine as thirst stimulus, 209 Calcium in beverage formulations, with sodium, chloride, potassium, and sucrose 27 losses in sweat, 138 plasma levels in potassium deficiency from training in heat, 120 Carbohydrate intake; see also Glucose concentrations in beverages affecting performance, 31, 32-33 during exercise, 56-59 in continuous exercise, 56-58 in intermittent exercise, 58 and reversal of fatigue, 101-105 gastric emptying of supplements in; see Gastric emptying postexercise, 59-66 comparison of carbohydrates in, 64-66 glucose infusions in, 63-64 and glycogen storage rates, 60 multiple supplements and amounts of glucose polymer in, 62-63 timing of, 61-62 prior to fatigue, affecting exercise performance, 105-108 timing of affecting performance, 45, 59, 105-108 during exercise, 99-109 in exercise of mild to moderate intensities, 108-109 postexercise, 61-62 and value of carbohydrate-electrolyte solutions, 3-4, 7-8 Carbonated beverages, effects

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FLUID REPLACEMENT AND HEAT STRESS during marching in heat, 212 Carbonic acid in beverages affecting quenching of thirst, 209, 211 Cerebrospinal fluid, sodium levels in and antidiuretic hormone release, 172 hyperosmotic solutions affecting, 189 Chloride affecting water and sodium absorption, 16 in Armyade, 113 in beverage formulations, 8, 18 glucose and fructose with, 27 sodium, potassium, calcium, and sucrose with, 27 sodium, potassium, and glucose with, 27 losses in sweat and urine after dehydration, 131-132 plasma levels dehydration affecting, 133 in exercise without fluid replenishment, 26 rehydration affecting, 149-152 Citrus drinks, effects during marching in heat, 212 Cola drinks, composition of, 29 Cold exposure at high altitude, respiratory water loss in, 181 Contraindications to carbohydrate-electrolyte supplements, 45 Creatine excretion, in potassium deficiency from training in heat 120 D Dehydration cellular, and thirst production, 172, 189 circulatory strain in, 26 electrolyte distributions in, 26-27 exercise performance in, 89 fluid intake in, 197-201 beverage composition affecting, 209-211 and gastric emptying during exercise, 86-87 hypotonic water deficit in in hydrated heat-acclimatized state, 178-179 in hypohydrated heat-acclimatized state, 180-181 in nonacclimatized state, 177-178 involuntary, 199 plasma volume and osmolality in, 143-160 in nursing home patients, 218-219 osmolality of body fluid in, 25 physiological responses to, 89-93 plasma volume decrease in, 25 pure water deficit in in hydrated state, 174-175 in hypohydrated state, 176-177 shock in, 176 sensations associated with, 162-163 and shifts in body fluid compartments, 127-140 sweat rate in, 4, 26 voluntary, 164, 169, 199

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FLUID REPLACEMENT AND HEAT STRESS Diabetes insipidus, fluid intake in, 204 Diarrheal diseases, 3, 111-114 Armyade in, 113-114 etiology of, 112 prophylaxis in, 112-113 in travelers, 112 worldwide distribution of, 112 Drinking behavior, factors affecting, 155-157, 198-208; see also Fluid intake Drugs, thirst-quenching properties of, 209 E Electrolytes; see also specific electrolytes distribution in exercise with fluid replacement, 26-27 plasma levels in exercise without fluid replacement, 28 replacement in prolonged exertion, efficacy of, 28-29 Energy depletion, cellular, affecting thirst, 184-189 Exceed, composition of, 29 Exercise carbohydrate supplements in, 56-59 and effects of postexercise carbohydrate supplements, 59-66 effects of water and saline feedings in, 27-29 fatigue in blood glucose levels affecting, 100 delayed by carbohydrate intake, 105-108 reversal by carbohydrate intake, 101-105 gastric emptying in, 30-31 concentration of carbohydrate affecting, 70-74 intensity of exercise affecting, 75-76 military applications of, 80-82 source of carbohydrate affecting, 74 glycogen depletion in, 5 glycogen storage after, 60 in heat, 4-5 affecting fluid intake, 198, 205-207 beverage preferences in, 210-212 body water loss in, 86-88 potassium deficiency from, 117-124 hypohydration affecting performance in, 89 intestinal absorption in, 17, 30 thirst in, 169-189 timing of carbohydrate intake in, 99-109 without fluid intake, effects of, 24-27 Extracellular fluid dehydration affecting, 87, 134 osmolality affecting cellular volume, 186 osmotic solutes in, 171, 197 percentage of total body water in, 171 rehydration affecting, 154-155 volume of hyperosmotic solutions affecting, 202 in potassium deficiency from training in heat, 120 related to body weight, 195

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FLUID REPLACEMENT AND HEAT STRESS F Fatigue blood glucose levels affecting, 100 delayed by carbohydrate intake, 105-108 reversal by carbohydrate intake, 101-105 Fluid balance, 197 aging affecting, 218-220 kidneys affecting, 203 osmotic control of, 170-172, 197-198 during rehydration, 152-153 Fluid compartment changes in dehydration, 127-140 thirst and drinking behavior in, 161-162 in heat exposure, 217 in rehydration, 153-155 see also Extracellular fluid; Intracellular fluid Fluid intake after dehydration, 197-201 beverage composition affecting, 209-211 barometric pressure affecting, 207-208 and body water loss during exercise in heat, 86-88 composition of beverages affecting, 208 contraindications to carbohydrate-electrolyte supplements in, 45 in diabetes insipidus, 204 in diarrheal disease, 113 environmental temperature affecting, 205-207 factors affecting, 155-157, 195-212 food consumption affecting, 163, 202-203, 208 free access to water affecting, 163 gastrointestinal distension affecting, 156, 203 humidity affecting, 207 insufficient amounts to restore water deficit, 164, 175 maximal amount of, 204 minimal amount of, 204 osmotic factors in, 202-203 preferred beverages during marching in heat, 210-212 satiation in, 203 and sensations associated with dehydration, 162-163 taste of drinks affecting, 164-165, 211 temperature of drinks affecting, 165-166 thirst affecting, 86, 161-162 during exercise, 169-189 value of carbohydrate-electrolyte solutions, 3-4, 7-8 see also Rehydration Food consumption, fluid intake associated with, 163, 202-203, 208 Fructose in beverage formulations 18, 29 chloride and glucose with, 27 glucose with, 27 and gastric emptying rate, 70 intestinal absorption of, 16 postexercise, compared to glucose and sucrose, 64-66

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FLUID REPLACEMENT AND HEAT STRESS G Galactose affecting gastric emptying rate, 70 Gastric emptying of beverages consumed during exercise, 30-31 concentration of carbohydrate affecting during exercise, 70-74 at rest, 78 during exercise concentration of carbohydrate affecting, 70-74 intensity of exercise affecting, 75-76 military applications of, 80-82 source of carbohydrate affecting, 74 and glycogen storage after exercise, 63-64 hypohydration affecting, 86-87 individuality of, 76-78 saline solutions and distilled water affecting, 157 study methodology double sampling method, 73, 80 effects of, 79-80 serial feeding method, 79-80 serial recovery method, 73, 79, 80 volumes of ingestate affecting, 80 Gastrointestinal function; see Gastric emptying; Intestinal absorption Gatorade, composition of, 29 Glucopenia, intracellular, and antidiuretic hormone release, 184, 188 Glucose affecting water and sodium absorption, 13-16 in Armyade, 113 in beverage formulations, 8, 18, 29 chloride and fructose with, 27 fructose with, 27 sodium, chloride, and potassium with, 27 sodium and potassium with, 27 concentrations affecting gastric emptying, 70, 74 gastric emptying rate for, 30 after serial feeding during exercise, 79-80 hypoglycemia in exercise, carbohydrate supplements affecting, 56 in heat stroke, 184 intravenous infusions during exercise, 103-104 postexercise, 63-64 plasma levels affecting ATP levels, 188 and fatigue after carbohydrate intake, 104-105 and fatigue delay during exercise, 100, 104 glucose infusions affecting, during exercise, 103-104 postexercise carbohydrate supplements affecting, 62-66 postexercise compared to fructose and sucrose, 64-66 intravenous infusions of, 63-64 sodium with, affecting homeostasis and performance, 32

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FLUID REPLACEMENT AND HEAT STRESS Glucose-electrolyte solutions, 3 nausea from 12% glucose in, 165 and plasma volume recovery in rehydration, 157 and reduction of involuntary dehydration, 143 Glucose polymers concentrations affecting gastric emptying, 70-74 and endurance during exercise, 56-58 gastric emptying rate after serial feeding during exercise, 79-80 postexercise compared to intravenous glucose infusions, 63-64 timing of, 61-62 in rehydration beverages, 18 sodium with, affecting homeostasis and performance, 32 sucrose with, and reversal of fatigue, 104-105 Glycerol, and antidiuretic hormone secretion, 187 Glycine in super rehydration solutions, 113 Glycogen depletion of and blood glucose as energy source, 99-100 and effects of carbohydrate supplements, 58-66 in prolonged exercise, 5 resynthesis after hypohydration in exercise, 93 storage affected by postexercise carbohydrate supplements, 62-66 supercompensation phenomenon, 122 synthesis in muscle in potassium deficiency, 121-122 Gookinaid ERG, composition of, 29 H Heart rate in exercise fluid intake affecting, 24, 26 hypohydration affecting, in heat, 92 Heat acclimation to fluid intake in, 197-201 salt consumption in, 41 sweat sodium losses in, 178-184 aging affecting body fluid responses to, 218-225 and effects of hypohydration, 89-93 exercise in, 4-5 affecting fluid intake, 197, 205-207 and beverage preferences, 210-212 body water loss in, 86-88 hemodilution in, 215-216, 217 aging affecting, 224-225 plasma volume changes in, 215-225 potassium deficiency from training in, 117-124 vasodilation in, 215, 217 Heat illness hypoglycemia in, 184 intestinal water absorption in, 44 predisposing factors in, 41-43 prevention with replacement

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FLUID REPLACEMENT AND HEAT STRESS beverages, case reports of, 37-38, 49-54 total body water values in, 43-44 Hematocrit changes in rehydration, 148-149 dehydration affecting, 132 Hemodilution, heat-induced, 215-216, 217 aging affecting, 224-225 Hemoglobin levels changes in rehydration, 148-149 dehydration affecting, 132 Humidity, and fluid intake, 207 Hydration program in prevention of heat illness, 38 Hydrogen ion concentrations of various beverages, 212 Hyperosmotic solutions, affecting fluid intake, 172, 202 Hypertonic solutions saline, affecting thirst and water intake, 161-162 sugar, effects in prolonged exercise, 27-28 Hypoglycemia in exercise, carbohydrate supplements affecting, 56 in heat stroke, 184 Hypohydration; see Dehydration Hypothalamic temperature affecting fluid intake, 203 Hypotonic solutions effects in prolonged exercise, 27-28 saline and gastric emptying rate, 157 intestinal absorption of, 157 Hypotonic sweat losses heat acclimation affecting, 178-184 in nonacclimatized state, 177-178 Hypovolemia and extracellular fluid loss, 135 at high altitudes, 208 as thirst stimulus, 162 see also Plasma volume I Insulin levels, postexercise carbohydrate supplements affecting, 62-66 Interstitial fluid changes after dehydration, 134, 137 percentage of total body water in, 171 Intestinal absorption, 11-18 anions affecting, 16 of beverages consumed during exercise, 30 electrolytes in fluid replacement affecting, 17-18 exercise affecting, 17 of fructose versus glucose, 16 segmental perfusion studies of, 12-13 of sodium, glucose-stimulated, 13-16 of water, 13 exercise affecting, 30 glucose affecting, 14-15 in heat exhaustion, 44 tap water compared to saline solution, 157 Intracellular fluid dehydration affecting, 87, 134

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FLUID REPLACEMENT AND HEAT STRESS osmotic solutes in, 171, 197-198 percentage of total body water in, 171 rehydration affecting, 156, 156-157 volume of plasma osmolality affecting, 135, 138-139 related to body weight, 195 Inulin clearance in potassium deficiency from training in heat, 120 Isostar, composition of, 29 Isotonic beverages, effects in prolonged exercise, 7-28 saline, in quenching of thirst, 210 K Kidneys saline solutions affecting, 210 in water balance maintenance, 203 L Lemonade, composition of, 29 M Magnesium in Armyade, 113 losses in sweat, 138 plasma levels in exercise without fluid replenishment, 26 Meals-ready-to-eat (MRE), salt packets in, 39-41 Milk intake, effects during marching in heat, 210, 212 Muscle blood volume during exercise, 26 cellular injury from exercise in heat, 118-123 electrolyte changes during exercise, 26 glycogen in; see Glycogen increased potassium levels after training, 120, 122-123 metabolism affected by hypohydration, 92-93 N Neurologic factors affecting fluid intake, 203 O Occupational specialties affecting dietary requirements, 45 Orange juice, composition of, 29 Osmolality of plasma affecting drinking behavior, 155-156 and antidiuretic hormone release, 172-173 and changes in intracellular fluid volume, 135, 138-139 dehydration affecting, 25, 133 in heat exposure aging affecting, 221, 224 and plasma volume changes, 218 hydration affecting, 88 rehydration affecting, 149-150 and sweating rate in hypohydration, 91 and threshold for thirst, 173

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FLUID REPLACEMENT AND HEAT STRESS Osmotic concentrations of various beverages, 212 Osmotic factors affecting fluid intake, 172, 202 in control of water balance, 170-172, 197-198 in retention of ingested fluids, 209 P Palatability of beverages and fluid intake, 5, 164-165, 203, 210 sodium chloride affecting, 28, 29 pH of beverages examples of, 212 and quenching of thirst, 209 Phosphorus levels in potassium deficiency from training in heat, 120 Plasma volume affecting drinking behavior, 155-156 beverage formulations affecting, 28 dehydration affecting, 25, 134 in involuntary dehydration, 144 in heat exposure, 215-225 aging affecting, 218-225 decrease in, 217-218 and sweating rate during exercise, 91-92 transient increase in, 216 hydration affecting, 87-88 hypovolemia in heat exposure, 217-218 at high altitudes, 208 and loss of extracellular fluid, 135 as thirst stimulus, 162 percentage of total body water, 171 ratio to blood volume, 195 rehydration affecting, 154-155, 157-158 Polymers in various beverages, 29 Potassium in Armyade, 113 in beverage formulations, 8, 18, 29 sodium, chloride, calcium, and sucrose with, 27 sodium, chloride, and glucose with, 27 sodium and glucose with, 27 deficiency from training in heat, 117-124 increase in muscle after training, 120, 123 losses after dehydration, 31-132, 138, 152, 156-157 losses in heat stress, 39 plasma levels dehydration affecting, 133 in exercise without fluid replenishment, 26 rehydration affecting, 149-152 Proteins in plasma during heat exposure, 217 aging affecting, 221, 224, 225 R Rehydration in diarrheal disease, 113 and factors affecting drinking behavior, 155-157 fluid and electrolyte balance in, 52-153 fluid compartment changes in, 153-155

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FLUID REPLACEMENT AND HEAT STRESS and fluid intake with tap water and with saline water, 147-148 hematocrit and hemoglobin changes in, 148-149 in hypotonic water deficit heat acclimation affecting, 179-181 in nonacclimatized state, 178 and insufficient fluid intake to restore water deficit, 164, 175 osmotic threshold for thirst affecting, 174-177 plasma osmolality in, 149-150 plasma volume recovery in, 157-158 restoration of body fluids in, 163-164 in elderly persons, 164 and retention of ingested fluids in vascular space, 144, 157-158 super formulations with glycine and rice powder, 113 Renin activity in potassium deficiency from training in heat, 120 Rhabdomyolysis from exercise in heat, 118-123 Rice powder in super rehydration solutions, 113 S Saline solutions affecting sweat excretion, 210 intestinal absorption of, compared to tap water, 157 in quenching of thirst, 210 Salt intake affecting water requirements, 41 during heat acclimation, 41 with MRE salt packets, 39-41 potential overconsumption in, 39-41 Sensations associated with dehydration, 162-163 Shock, in pure water deficit, 176 Skin blood flow in dehydration, 25-26, 92 in heat exposure, 217 vasodilation in heat exposure, 215, 217 Soda waters affecting thirst, 210 Sodium in Armyade, 113 in beverage formulations, 8, 18, 29 affecting palatability, 28, 29 chloride, potassium, calcium, and sucrose with, 27 chloride, potassium, and glucose with, 27 potassium and glucose with, 27 in cerebrospinal fluid and antidiuretic hormone release, 172 hyperosmotic solutions affecting, 189 hyperosmotic solutions stimulating thirst, 172, 189 hyponatremia in prolonged exercise, 28 hypotonic sweat losses heat acclimation affecting, 178-184 in nonacclimatized state, 177-178 intestinal absorption of,

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FLUID REPLACEMENT AND HEAT STRESS glucose-stimulated, 13-16 leakage into cells affecting cellular metabolism, 186-188 losses after dehydration, 131-132, 152, 156-157 losses in heat stress, 39 and osmotic control of water balance, 172 plasma levels aging affecting, 219 dehydration affecting, 133 in exercise without fluid replenishment, 26 rehydration affecting, 149-152 in sweat, and losses in body fluid compartments, 135, 139 Splanchnic blood flow aging affecting, 225 heat affecting, 218 Sucrose in beverage formulations, 8, 29 glucose and sodium with, affecting homeostasis and performance, 32 and performance during exercise, 58 postexercise, compared to glucose and fructose, 64-66 sodium, chloride, potassium, and calcium with, 27 as thirst stimulus, 172, 189 Sweating and effects of fluid intake, 24, 26, 209-210 during exercise in heat, 86 and hypohydration, 4, 90-92, 198-199 hypotonic losses in heat acclimation affecting, 178-184 in nonacclimatized state, 177-178 plasma osmolality affecting, 218 and plasma volume changes in heat exposure, 217 and potassium deficiency from training in heat, 117, 121-122 Sweeteners in drinks affecting fluid intake, 164-165, 203 T Taste of beverages and fluid intake, 5, 164-165, 203, 210 sodium chloride affecting, 28, 29 Temperature of beverages, affecting fluid intake, 164-166, 212 of body fluid intake affecting, 24, 26 hypohydration affecting, 87, 89-90 in older men during heat exposure, 221 and sweating rate during hypohydration, 90 environmental cold, at high altitude, respiratory water loss in, 181 and fluid intake, 198, 205-207 hot; see Heat of hypothalamus, affecting fluid intake, 203 of water, affecting fluid intake, 212 Thirst beverage composition affecting, 153-155

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FLUID REPLACEMENT AND HEAT STRESS in cellular dehydration, 172 cellular energy levels affecting, 184-189 during exercise, 169-189 and fluid intake, 24-25, 86 osmotic threshold for, 173 and concept of free circulating water, 170, 174 impact on rehydration, 174-177 perception affected by age, 219 sensations associated with, 162-163 stimuli for, 161-162, 172 Timing of carbohydrate intake and performance during exercise, 45, 59 postexercise, 61-62 U Uric acid excretion in potassium deficiency from training in heat 120 Urine concentration in hypohydration, 203 creatine excretion in potassium deficiency from training in heat, 120 electrolyte losses after dehydration, 131-132 excretion affected by acidity of beverages, 209 potassium excretion in potassium deficiency from training in heat 120, 121 sodium excretion affected by age, 219 uric acid excretion in potassium deficiency from training in heat 120 V Vasodilation from heat exposure, 215, 217 Vasopressin; see Antidiuretic hormone W Water body water loss, 86-88 in dehydration, 134, 147 ratio to plasma water loss, 139 deficits of; see Dehydration free circulating, 170, 174 gastric emptying of, 30-31 after serial feeding during exercise, 79-80 exercise intensity affecting, 75-76 insensible loss of, 181, 205 intake of; see also Fluid intake affecting homeostasis and performance, 32-33 effects during prolonged exercise, 27-29 requirements affected by salt consumption, 41 thirst affecting, 24-25 intestinal absorption of, 13 exercise affecting, 30 glucose affecting, 14-15 in heat exhaustion, 44 tap water compared to saline solutions, 157 losses in sweat and urine after dehydration, 131-132 movement between fluid compartments after

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FLUID REPLACEMENT AND HEAT STRESS dehydration, 127-140 respiratory loss of, 181 total body values age affecting, 195-197 in extracellular and intracellular fluid, 171 gender differences in, 195 in heat-exhaustion patients, 43-44 rehydration affecting, 154 volume related to body weight, 195 withholding of, and effects of exercise, 24-27