Exam 4: Basic body composition Lecture Flashcards
body water is the ________ single component of the body
largest
t/f approximately 60% of total body weight
t
functions of water
1.
2.
3.
4.
5.
- solvent, medium and substrate for chemical reactions
- absorption and transport of nutrients
- temperature regulation
- excretion of waste products
- lubricant and buffer for physical shock
T/F Water is the most important nutrient and expect for minerals, the simplest nutrient
T
T/F Electrolytes, part of the mineral class of nutrients discussed in the previous chapter,
have a myriad of physiological roles, some of which are serving source of energy,
synthesis of FFA
F
T/F Since water is an essential nutrient, it cannot be produced by the body
→ false, we make
water in our body
T/F Whole body sweat rate typically ranges from 0.5 to 2.0 liters (1.1-4.4 lbs) per hour but
can exceed 3 liters (6.6 lbs) per hour in approximately in 2% of athletes
T
T/F In a review studies since 2008, Mcnaughton and others indicated that 300 mg per
kilogram body weight( 1 ounce for the average
F
1000mg of salt provides 400mg of sodium → 40% of salt is sodium (Na), important to
know, 60% chloride (CI)
-Intracellular water is
-Intracellular water is inside of a cell, intracellular fluid is 60-65% of total body water
-Intercellular water is
-Intercellular water is water between the cells
-Intravascular water is
-Intravascular water is water inside the blood vessels
-Hematocrit
-Hematocrit (% packed blood volume), most is water inside of the cells
why is hematocrit important?
-important for sports nutrition because sometimes the blood volume expands and you can tell by hematocrit going down and everything goes to the liver
interstitial fluid
water in between cells
The U.S. National Academies of Sciences recommend daily water intake of ____ liters for males and ____ liters for females,
3.7
2.7
Only ____% of people meet these guidelines, according to NHANES data
40
Water comes from _____ (about 80%) and ____ moisture (20%), with foods like fruits, vegetables, and meats contributing significant water content.
beverages
food
fluid losses through ____, _____, _____, and _____
fluid losses through sweat, urine, respiration, and feces
T/F High-protein diets can increase urine output, as proteins produce urea
T
Can water be produced in the body?
yes, Metabolic processes also generate water. For instance, breaking down glucose produces metabolic water.
t/f muscle and nonfat tissues hold more water than fat
t
Extracellular Water: Accounts for
35–40% (14–17 liters)
Extracellular Water: is subdivided into
Interstitial Water: Surrounds cells (8–9 liters).
Intravascular Water: Within blood vessels (3–4 liters).
Miscellaneous Compartments: Includes cerebrospinal fluid and others (1–3 liters).
interstitial water is
surrounds the cells
intravascular water is
within the blood vessels
Proteins: Bind water in tissues, with plasma proteins like albumin helping maintain vascular water through c____ ________ ________.
Proteins: Bind water in tissues, with plasma proteins like albumin helping maintain vascular water through colloid oncotic pressure.
the function of water “ lubricant and buffer for physical shock” is particularly important for football players because water can protect hearts and joints leading to less injury
t
Intake/Input of water: majority of water comes from beverages and food
yes >90%
less than 10% of water intake/input comes from metabolic reactions within the body
true
the most variable water loss occurs by ____
sweat: type of exercise, location, environment…
nonathletes have the most amount of water loss by ____
urination
metabolic pathway that produces water?
ETC
If losses exceed consumption.. What do we end up with?
DEHYDRATION
Water accumulation→ end up with
edema
What is hypervolemia?
Hypervolemia is a condition where your body has too much
fluid. Another name for hypervolemia is “fluid overload” or “volume overload.” Your body
is made up of 50% to 60% fluid, which includes water, blood and lymphatic fluid
thirst is a symptom of ?
dehydration
25% of our blood goes through our kidneys(blood lovers) every minute, so they can filter out the bad stuff and selectively reabsorb
When does dehydration impair performance?
Some studies say Impair performance occurs with just 2%-3% of BW
Running Times & Dehydration:
-sometimes you want to be around 1-2% less of body weight in a race because then you are lighter and beat the heavier people that have been topping off with fluids
- studies say the fastest athletes in races are often more dehydrated than the slower athletes → less weight , more efficient ?
sweat loss process
increases the temp of blood & osmolarity, osmolarity is how many particles are dissolved in solution, if you lose water→ everything in the blood becomes more concentrated and osmolarity is higher → higher osmolarity sends a signal to hypothalamus, hypothalamus is what senses this change in concentration (osmolarity in our blood) and sends signals that causes to feel things like thirst and tells the pituitary gland to send antidiuretic hormone (ADH) into the circulation , ADH prevents you from peeing, telling you to hold on to your water
-It important for athletes when they first start to feel thirsty to start drinking some water
Study: fluid intake of elite basketball players from the UK, they found out the players that drank later were never able to prevent dehydration or rehydrate during half time, they all failed to rehydrate because they let themselves get behind in the beginning of the game. The players that were able to maintain their hydration in the beginning of the game and throughout had the best performance!
-need to prevent the dehydration from the beginning to have optimal performance
water influence on distance
They made them 2% dehydrated and then they measure their performance
~10% drop in plasma volume (1.9, 1.6, and 2.1% wt loss)
Results:
-1500m: .16 min slower when they were dehydrated, this wasn’t statistically different -5000m:1.13 min slower and this was statistically different
-10,000m: 2.13/3 min slower and this was statistically different
In conclusion, dehydration may not impair performance if the event is short enough but if the event is long enough it does impair performance
Rating of perceived exertion figure, study
dehydration starts creeping in and feeling harder and harder at 80-120 mins→ rating of perceived exertion at 18 feels very hard at no fluid, then small fluid etc.
-another study: fluid + carbs combine were the fastest to complete the task overall
-when they got more fluid they were faster, they were able to do certain amount of work in less time vs placebo
-Overall, when you consume fluid to prevent dehydration, if it’s a task that will benefit from carbohydrates, you should consume carbs along with fluid too! Ex: sports drinks
Humid weather:
Sweat does not evaporate readily
- Athlete “dripping” with sweat may be missing the cooling benefit
- Picture from book with the sun, heat stress, heat loss
Study: 10 min mile → .50 sweating rate
- 1 kg of water =1 Liter of water
- What % dehydration 120# female athlete and loses 2.3 L sweating rate for 1 hour
exercise → 2.3kg/55kg of water= 4.2 % of dehydration→ leading to impair performance
and thirsty, For marathon: 11% dehydration for 2 hours can die from this
- Heat and humid a lot worse than cool and dry weather
How can these problems be avoided in terms of dehydration, heat climates,heat illness?
If unavoidable, should build up tolerance (acclimation to the climate)
- Increases sweat production for better cooling( if you better sweater, better cooler) & decreases electrolyte loss
- Should be done safely (ie. gradually increase intensity & duration in heat)
- Usually takes about 1-2 weeks
- Restricting water does not aid in acclimation, may impair performance
2.Exercise during coolest part of day
3. Wear cool clothing
4.Drink cold fluids(with carbs & electrolytes if the event would benefit from carbs) →may want to hyperhydrate (consume extra fluid right before your performance to benefit)
Why do heat and dehydration affect performance?
-Lower blood volume
- Decreased cardiac output
-Decreased work capacity
-Lower blood volume → poor thermoregulation→ heat injury→ decreased work capacity
2 main ways dehydration impairs performance: heat stress and decrease cardiac output→ both can impair performance
why do heat and dehydration affect performance?
Study: more fluid restriction results in higher core body temperature, lower cardiac output,less fluid being consumed the lower the cardiac output, higher heart rate, and a lower stroke volume
Heat Cramps:
-thrist, chills, goosebumps, clammy, throbbing heart beat, nausea -maybe muscle pain & spasms
Heat Exhaustion:
-reduced sweating, dryness in mouth, weak/rapid pulse, headache, dizziness, fatigue -normal to elevated body temperature
Heat Stroke:
-Very high temp. (up to 108+F)
-lack of sweat, dry/hot skin, visual problems, deafness,swollen tongue, nervousness, hallucinations, aggression, unsteady walking
-may collapse, lose consciousness, and convulse
-When you get to this point, you need immediate treatment because you have to cool the body right away first and then call the hospital
cooling method
if you can get at least .15 degree celsius (optimal cooling) per min of cooling then the person will survive the heat issue
treatment
Other treatments:
- Cool, rapidly absorbed fluids (2 cups of fluid for every pound lost)
- Cool or shaded environment
- none/little/light clothing
fluids before exercise
4 hours
dark urine drink more
before competition
euhydration status
4 hours before
5-7ml
too mch cause
dilutional hyponatremia
during competition
prevent excessive dehydration >2% loss
0.4-0.8l per hour
Na K
after competition
fully replace fluids
1.5 l for kg body wieght loss
