Hydration Flashcards
(78 cards)
1
Q
Purpose of water in body
A
- cushion/protection
- water and electrolyte balance (osmotic pressure)
- carries oxygen, nutrients, hormones, etc
- carries waste products away for excretion
- solvent for minerals, vitamins, AA, glucose
- functioning of our senses
- regulation of body temp
2
Q
When does heat production increase
A
Higher BMR, infectious disease, shivering, exercise
3
Q
60-80% of metabolic heat produced during exercise is converted
A
To heat (within the body)
4
Q
How is heat removed from body
A
Radiation, conduction, convection and evaporation
5
Q
In sport and physical activity what would impact our ability to sweat (evaporate water)?
A
- physical environment (heat, humidity)
- hydration
- intensity, duration, body size, training, fitness levels
- equipment (what wearing)
6
Q
What is most essential nutrient
A
Water
7
Q
Losses of water
A
Perspiration, respiration, urine, feces
8
Q
What produces water
A
Metabolism
9
Q
AI for water
A
Adult males= 3.7L
Adult females= 2.7L
10
Q
UL for water
A
No UL set
11
Q
What does water include
A
All foods, beverages and water
Anything liquid at room temp
12
Q
How does metabolism produce water
A
Water is by product when break down macronutrients for energy
13
Q
What is water held in body with
A
Protein, CHO and electrolytes
14
Q
How much of body is made up of water
A
50-60%
15
Q
What is water regulated by
A
Regulated by kidneys (euhydration or normohydration)
16
Q
How do you know if you’re adequately hydrated
A
Thirst mechanism
Color of urine
17
Q
When is best time to check urine
A
Right in morning
18
Q
3 hydration statuses
A
Hypo- or dehydration
Euhydration
Hyperhydration
19
Q
Effects of hypohydration
A
Detrimental to performance
Heat illness, sickness
Lose consciousness
Death
20
Q
Effects of euhydration
A
Good performance
21
Q
Effects of hyperhydration
A
No advantage
22
Q
Hyponatremia
A
Low sodium in blood
- if sweating lots cant just have plain water
23
Q
Effects of hyponatremia
A
Confusion, fainting
Fatal is misdiagnosed
24
Q
Practical hydration goals
A
- getting comfortable with hydration during intensity
- consume fluids to match sweat rates (or minimize drop in BW)
25
How much water include with each meal +snack
250-500ml
26
When training in heat-
Monitor for signs of dehydration
27
How much water or fluids with recovery
500-750ml
28
How much sweating may reduce performance
As little as 2% loss of body weight due to sweating
29
What exercise does loss of BW due to sweating affect most
Most severe on aerobic endurance performance
- especially hot, humid environments
30
2 types of loss of BW due to sweating
Voluntary and involuntary
31
When is it likely that fluid deficits during exercise will reach levels likely to effect performance
When exercise duration exceeds 60mins and when ambient temperature is high
32
Factors to think about (sweating)
Hydration status at start of training
Equipment worn
Cold temperatures
Training status/individual sweat rates
33
How can hydration status be measured
Assuming athlete us in energy balance, daily hydration can be estimated by tracking early morning body weight (on very accurate scale) measured upon waking after morning voiding
34
Acute changes in BW=
A shift in body water
35
What else can be used to measure hydration status
Specific gravity and urine osmolality
36
osmolality
Refers to amount, or concentration of dissolved substances (solute) in a solution (osmol/kg solvent)
37
When does osmolality increase and decrease
Increase with dehydration (hypertonic)
Decreases with overhydration (hypotonic)
Water movemetn from hypo to hypertonic
38
Osmolarity
Number of solute particles per litre of solution
39
Value <1.020
Considered adequate for hydration status; usually measured upon waking
40
Sweat rate calculation
1. Weigh prior to workout, record in kg (1kg = approx 1L)
2. Weigh post workout, record in kg
3. Sweat loss in litres= BW before- BW after (add any fluids consumed during training)
4. Divide sweat loss by length of workout (min or hr)
41
Pre workout 74kg
Post workout 73kg
500ml water consumed in 1 hr training
74kg - 73kg = 1 + 0.5L = 1.5L/hr
42
What does the assumption 1kg=1L ignore
Other confounding factors: fuel use, CHO oxidation
43
Limitation with fluid balance assessment: what are conditions that are specific in which testing took place
Temperature
Training status
Humidity
Intensity/duration
Hydration status at start
Acclimitization
44
As bw increases what happens to sweating
Increases
45
As intensity increases what happens to sweating
Increases
46
As temperature increases what happens to sweating
Increase
47
The old ACSM recommendations for hydration
Athletes should aim to replace 100% of their BW losses during exercise and to ingest supplemental sodium (no performance advantage)
48
New ACSM recommendations for hydration
Fluids should be replaced at a rate that will insure that BW losses during exercise do not exceed 2%
49
Dehydration and the effects on exercise performance
- impaired performance
- greater reliance on CHO for fuel
- might degrade mental/cognitive performance
- impair vigilance (errors)
-impair reaction time
- may be factor in GI distress
- increased RPE
50
Does dehydration matter
- in reality performance impact of dehydration is less clear
Athletes complete events with variable fluid intake
51
What are guidelines for dehydration and reality
Limit %BW loss to within 2% of starting BW
Reality: large variability with % change in BW from -8% to +5% at end of marathon
52
Physiological effects of dehydration
Decrease plasma volume-> increase plasma osmolality + blood viscosity -> decrease central blood volume + filling of heart -> decrease SV + increase HR -> decrease cardiac output -> decrease blood flow + sweat rate
53
What does all the physiological effects do
Increase core temperature
54
Effects of starting a training session in a dehydration state (hypohydration)
3.2% drop in mean power output
Impairs endurance performance
55
What is sweat made up of
99% water and 1% electrolytes
56
Major electrolytes in sweat
Sodium and chloride
57
What is sodium content of sweat
Variable, depends on training status, heat acclimitization, hydration status
58
If sweating lots what do we need to replace
H20 and electrolytes
Can’t just drink water
59
Exercise associated hyponatremia
Low concentration of sodium in blood
<135mmol/L
60
What are symptoms of hyponatremia
- very similar to dehydration
- often can be asymptomatic (biochemical hyponatremia)
61
What is hyponatremia typically associated with
- endurance events (long duration, low intensity)
- increased availability of fluids (before/during/after)
- slower athletes
- lighter body weight/smaller individuals/females
62
Signs and symptoms noted with serum sodium <130mmol/L
Bloating
Puffiness of hands and feet
Nausea
Vomiting
Headache
63
Signs and symptoms of severe cases <120mmol/L
Seizures
Coma
Respiratory arrest
Permanent brain damage
Death
64
Electrolytes
Substance which, in solution, conducts an electrical current
65
Primary electrolytes
Sodium, chloride, bicarbonate, surface, magnesium, calcium
66
AI for sodium and what it doesnt take into account
1,500mg/day
No allowances for increased sodium losses with sweating
Takes into consideration inactive adults
67
UL of sodium and daily value used on food labels
2,300 mg/day UL
2,400 DV
68
Do other electrolytes have significant role in hydration before, during, or after
No emerging evidence to suggest anything other then sodium has significant role
69
Major function of sodium
Principe electrolyte in extracellular fluids, serves to maintain normal body fluid balance & osmotic pressure
70
What is sodium critical for
Nerve impulse transmission and muscle contraction
71
What is sodium also a component of
Sodium bicarbonate
- helps maintain normal acid base balance
72
During intense exercise what happens to sodium concentration
Increases in blood to help maintain blood volume
73
What else increases during exercise to conserve body water and Na supplies
Antidiuretic hormone (ADH)/vasopressin
74
What do endurance athletes with high sweat rate/salty sweat have to do
Need additional sodium during and after exercise
75
What should be included during endurance sport
Sodium if sweat losses high especially if exercise lasts more than 2 hr
76
Before exercise for sodium recommendations
Foods/fluids containing sodium can help retain fluids consumed prior to exercise to establish euhydration
77
Sodium reconditions for after exercise
Restoration and replacement of sodium is prerequisite for effective restoration and maintenance of euhydration
78
Is coconut water a good sodium and hydration drink
Good for hydration not a lot of sodium
Need to eat sodium product
