Chapter 7: Water
what is the recommended fluid consumption after exercise?
1.25-1.5 L
what is the sweat loss range?
100 mL to several L per day
How much of the body weight can be lost during exercise?
2-7%
what percent of body weight is water?
40-80%
what is one way the body can make water?
Aerobic metabolism
What do scientists theorize that exercise-related muscle cramping is due to?
Altered neuromusclular control
How should athletes hydrate before exercise?
Based on their individual preferences
what is the primary intake of water?
Beverages and foods
what does hypoantermia do to the cell? why?
Causes cell swelling because the low concentration of Na in ECF causes the water to go to the high concentration of Na in the ICF
What is the best (easiest) way for an athlete to determine their hydration status?
Evaluate thirst, urine color, and body weight first thing in the morning
T/F: small disruptions in plasma sodium concentrations can have serious physiological and medical consequences
F: large disruptions
T/F: excess sodium is excreted through sweat
F: urine
what fluid compartment contains the most amount of water?
Intracellular fluid
When does sodium and carbohydrates fluids become necessary?
More than 2 hours of continuous exercise (fluid losses of 1 L to 2 L)
what are they symptoms of hypokalemia?
Muscle weakness and cardiac arrhythmias
What kind of cells have the most amount of water (think ICF)?
Myocytes
what are the common cations in the body?
Na, K, Ca, Mg
Does the DRI for Na apply to athletes?
No
will losses of 1-2% of body weight impair performance in exerercise that is less than 90 minutes?
No
Is glycerol hydration proven to be beneficial or impairative?
No; it does not indicate improved performance or impair performance
what is the primary intercellular cation that is found in most foods?
Potatssium
T/F: all cell membranes are freely permeable to water and can move through cell membranes
T
What are some of the functions of water in the body?
Transports substances throughout the body, facilitates in thermoregulation, and is critical to physiological processes
Can electrolyte loss during exercise be substantial?
Yes
Do both subcompartments of ECF have identical electrolyte compositon?
Yes
Does the water content within cells and tissues vary?
Yes
can hyperhydration and glycerol be beneficial to performance?
Yes
What is hypohydration?
a state of being at an insufficient volume of water in the body
What are the effects of dehydration with exercise?
adverse impact on core temp. and exercise performance
T/F: rehydration most important during exercise
after
what are two factors associated with a lower percentage of body water?
being older and having large amounts of body fat
what athlete can be seen to have hyerkalemia?
body builders because of the intake of K supplements
what does the amount of total body water depend on?
body size, gender, age, and body composition
what body tissue contains the least amount of water?
bone and adipose tissue
what are other nutrients that may be ingested with electrolytes and water during exercise?
carbohydrates
what macronutrient can cause GI distress from sports drinks?
carbohydrates
what does hypotonic cause?
cell swelling (think of a snowman)
What is osmolarity influenced by?
concentration of solutes, particularly certain electrolytes
what do thirst and hunger mechanisms usually lead people to do?
consume water in excess that is then easily excreted
what is the primary goal for fluid consumption during exercise?
delaying dehydration
what is hydrostatic pressure?
difference in pressure that causes a shift in fluid concentration
what is glycerol in association to hydration?
easily absorbed nutrient that exerts an osmotic force to attract water
what does sweat contain?
electrolytes, minerals, urea, lactate, uric acid
what are factors affecting sweat rate?
environmental conditions, exercise intensity, and clothing
what is the optimal amount of water to support fluid balance?
euhydration
what are the current states of water in the body?
euhydration, hypohydration, hyperhydration
What is hyperhydration?
excess amount of water that is usually TEMPORARY
what is EAMC? what are some of its causes?
exercise-related muscle cramping; dehydration, electrolyte loss, lack of stretching
when is glycerol hyperhydration beneficial?
exercising in the heat
What does heat cramps seem to be due to?
exercising in the heat that causes sodium depletion and dehydration and muscle fatigue
what fluid compartment causes fluid movement in the body?
extracellular fluid
why do males have more water than females?
females have more body fat and smaller bodies
what is interstitial fluid?
fluid between cells
How does fluid loss rate compare to fluid absorption rate?
fluid loss rate is faster than absorption, that is why it is difficult to maintain balance during exercise
how can sodium be ingested?
foods, fluids, salt tablets, and supplements
What is hyperthermia?
high body temperature
What should the hydration strategy encompass?
hydration/ electrolyte status, goals, actions to do that, and reassessment
what are the two types of pressures that stimulate water movement?
hydrostatic and osmotic
what is the concentration of all solutes being greater outside than inside the cell?
hypertonic (water is being pulled out)
when it hypoantremia seen? how is it fixed?
in prolonged endurance because of Na losses during exercises causes the plasma levels to become too low; sodium replacement
What is a byproduct of K deficiency?
increase in BP and bone turnover
What is hyperhydration before exercise?
increasing fluid levels about normal prior to exercise to reduce hypodyration and delay performance decline
what are the two ways water is lost?
insensible and sensible
what are the two compartments within extracellular fluid?
interstitial fluid and plasma
why is hyperhydration dangerous?
is can cause cells to swell too much and the CNS is too sensitive to swelling
what are the types of tonicity?
isotonic, hypertonic, and hypotonic
what organ regulates Na levels?
kidneys
What is hypovolemia?
low blood volume that is caused by water loss through heavy sweating
what does a low potassium intake reflect?
low daily fruit and vegtable intake paired with a high intake of processed foods
Does the FDA regulate energy drinks?
no
Is water sodium manditory for pre exercise?
no
is hypokalemia common in healthy individuals?
no
is lymph the same as interstitial fluid?
no
what water compartment regulates the body temperature?
plasma
What is hypoatremia? can it be fata?
plasma sodium being too low that can create sodium disturbances; Yes
how does the body compensate for low water consumption?
reducing urine output (with a high solute concentration)
what is the process of gaining water?
rehydration
what is the neuromuscular problem associated with cramps?
relax and contract signals get jumbled resulting in a cramp
what is hypokalemia?
severe deficiency in potassium that is caused by prolonged gi destress or excretion through urine
What are the common anions?
sodium bicarbonate (HCO3), phosphate(PO4) and protien
What is a good strategy to dramatically increase sodium intake during prolonger exercise?
sports drinks or sodium/ salt supplements
what is euhydration
state of being adequately hydrated to meet physiological demands
how does the body use water for thermoregulation?
sweat is evaporated off the body, which helps to cool the outside
why are there losses of Na and Cl during heavy sweating?
sweat moves the tubules at a rate that is too fast for reabsorption
how can sodium be lost through the body?
sweat, urine, feces
what organ does systematic circulation not include?
systemic circulation
what is osmotic pressure?
tendency of water to move from an area of low solute concentration to an area of high concentration
what is dehydration?
the PROCESS of losing body water and moving from a state of euhydration to hypohydration
what is tonicity?
the ability of a solution to modify the volume of water in cells
how does exercise cause an increase in insensible ventilation?
the more we exhale, the more water is lost from the body
how does exercise change the fluid homestasis?
the role that fluids play in thermoregulation that creates acceleration of loss and increased dehydration
what does sweating do to the fluid balance?
there is a fluid loss in the ECF with a high Na concentration that pulls the water out of the ICF- causes cell shrinking (hypertonicity)
what are some risks with energy drinks?
they mask the real reason for fatigue
What is the assessment triangle tool for hydration?
thirst, weight , and urine color when there is an overlap of at least two of the conditions
why does water move during osmosis?
to dilute high concentration of solutes and restore balance
what are the most practical ways to analyze hydration status?
urine color and body weight
what are examples of insensible?
ventilation and non-sweat diffusion
When are substantial sodium losses in athletes seen?
very long duration of exercise that is longer than 4 hours
what is distribution of water throughout the body regulated by?
volume of water and osmolarity of the ECF
what controls the amount of water in the ECF?
water AND sodium intake and losses, and compensatory regulatory mechanisms
how is water lost insensibly on the skin?
water is used to hydrate the skin
what are the two major aspects to fluid balance?
water volume and concentration of solutes in the body fluid
Do most sedentary individuals regulate their fluid balance easily?
yes
can the contents in sweat vary?
yes
can hyperhydration and hypohydration affect performance?
yes, adversely
Does cold dry air cause more insensible water loss?
yes, because more water is needed to humidify the air
Is K intake low in the US?
yes- less than 3% obtain adequate intake
Do athletes needs a rehydration and electrolyte plan? when is the plan most necessary?
yes; when preparing for a competition with periodic evaluation
