Lecture 5 - Fluid

Question 1

How do we take water in?

Answer 1

Food 700-1000ml
Liquid 550-1500ml
Metabolic Water 200-300ml

Question 2

How much water total do we take in per day?

Answer 2

1450-2800ml/d

Question 3

How do we get water out of our bodies?

Answer 3

Kidneys 500-1500ml
Skin 450-900ml
Lungs 350ml
Feces 150ml

Question 4

Why % dehydrate can our body handle and not handle?

Answer 4

• Under 2% BW we tolerate dehydration quite well
• Over 5% is when we start to see the problems
- Even 1% dehydration (1%bodyweight) can effect us

Depends on what we are doing and how we tolerate i

Question 5

What is fluid intake dependent on?

Answer 5

• Depends on sweat rate

- Determined by change in body wt before and after activity

Question 6

What % body wt should we aim for in terms of water lost?

Answer 6

Aim for no more than 1.5 to 2% body wt loss

- We know 2% is tolerated, but at 1% there still may be concentration issues

Question 7

Ideally what do we aim for with activity in terms of fluid intake?

Answer 7

Ideally we aim for no weight loss during activity

Question 8

What conditions make someone lose more water?

Answer 8

humidity, 
intensity, 
duration, 
clothing, 
acclamation to a climate, training status, 
genetics 
-are what can affect sweat rate

Question 9

How do we determine how much % change we see?

Answer 9

• Pre/Post Weight is how we determine how much %change we see (nude weighing best)

Question 10

What does weighing someone pre and post activity allow you to determine?

Answer 10

○ Estimation of how much water you need during activity

Question 11

What is the goal before activity starts?

Answer 11

to arrive to your activity properly hydrated

Question 12

What are the recommendations for adults in terms of hydration before activity?

Answer 12

500 to 700ml of fluid 60-90min before, doesn’t have to be all at once

Athletes 5-7ml/kg 4hr before, if urine is dark or not produced another 3-5 ml/kg 2hr before

Question 13

What are the recommendations for children in terms of hydration before activity?

Answer 13

400ml of fluid 60-90min before

Question 14

What happens by the time you re already thirsty?

Answer 14

By the time you are thirsty, you are already dehydrated 1-2%

○ Our mechanism only hydrates up 40-50% of the way, so we are still 40-50% dehydrated

Question 15

ow much fluid should be taken in during activity?

Answer 15

Enough to prevent body wt loss and to not cause any body wt gain

Question 16

What are the hydration recommendations for fluid during activity?

Answer 16

○ 150-350ml of fluid every 15-20mins (~1L an hour)

-Need to train stomach to do this

Question 17

What are other factors that need to be considered when thinking about how much fluid you should take in during activity?

Answer 17

Tolerance
Temp
Exercise or physical activity workload

Question 18

What should be done for children and adolescents during activity?

Answer 18

For children and adolescents regular breaks should be provided and fluid consumption encouraged

Question 19

How much fluid should you consume after activity?

Answer 19

Enough to replenish body wt (little extra to account for EPOC)

1g=1ml of fluid (1kg=1L)

Estimate about 1-1,5L/kgbody wt lost

Question 20

How quickly after activity should you consume fluids?

Answer 20

Should be immediately and as tolerated so not immediately

Question 21

What should you also keep I mind after activity?

Answer 21

May also need to consider continued sweat losses post exercise

Some recommend rehydration at a rate of 130 to 150% of body mass loss

Question 22

What are the signs and symptoms of heatstroke?

Answer 22

○ Body temp 40C or higher
○ Altered behaviour or mental state
-Confusion, agitation, slurred speech, irritability, seizures
○ Alteration in sweating
- Hot weather: skin hot and dry
- Strenuous activity: Skin is hot and moist 
○ Nausea and vomiting
○ Flushing
○ Rapid and shallow breathing
○ Rapid heart rate 
○ Headache

Question 23

What does the toleration of dehydration dependent on?

Answer 23

• Tolerance to dehydration cab be dependent on the ambient temp
- In 30degrees you are less tolerant than 5 degree weather

Question 24

If someone has heatstroke what should you do?

Answer 24

Call 911 is the first thing you should do
- high temp can result in permanent damage, then you start to cool them down, take off clothes, then ice (back of neck, top head, groin, and under armpit)

Question 25

Why are electrolytes sometimes beneficial?

Answer 25

When you sweat you loose fluid and salt.

Electrolyte may also need to be replenished but this is dependent on
• Length of activity
• Tempo

Question 26

When you sweat what do you lose?

Answer 26

Sweat consists of fluid and salt

Lose moer water than salt, salt loss is genetic

Question 27

Do we need to be concerned about how much salt our body has?

Answer 27

Most of us get enough salt in our diets and can rely on this prior to activity 3100-3200mg of Na per day, supposed to be getting 1500mg, so we don’t really need to supplement the salt with Gatorade or something

Question 28

Where do we get most of our salt intake from?

Answer 28

Bread doesn’t have a lot of salt but we eat a lot of bread so its our main source, mixed dishes, processed meals, cheese, soups.

Question 29

What have sports drinks been formulated to do?

Answer 29

Sports beverages have been formulated specifically to enhance the thirst mechanisms

Question 30

What does salt also enhance?

Answer 30

Salt also enhances the absorption of water and sugar, typically found in these beverages such as gatorade

Question 31

How is thirst triggered?

Answer 31

○ Low blood volume (water content of blood drops)

○ High blood salt concentration (triggers thirst mechanism)

Question 32

When you only drink water what happens in terms of thirst mechanisms?

Answer 32

Dinking water only to replenished fluids lowers the salt concentration and can prematurely turn down the thirst drive
○ Could lead to less fluid consumed

Question 33

What does the salt in gatorade also help with?

Answer 33

Salt put into Gatorade to help absorb carbs better

○ Increasing blood volume and keep the salt content a little bit higher to which makes you drink more vs. if you drink water you increase blood volume and decrease blood salt concentration

Question 34

What is hyponatremia?

Answer 34

Low blood Na

Question 35

What are the symptoms of hyponatremia?

Answer 35

Symptoms include: 
muscles cramps, 
loss of appetite, 
fatigue, 
nausea, 
vomitting, 
dizziness
confusion

Question 36

What is hyponatremia caused by?

Answer 36

Caused by too much water consumed, typically resulting in an increase in body wt during activity
-Usually get it when you drink a lot of water

Question 37

Who is more likely to get hyponatremia?

Answer 37

More common in older adults living alone because they drink a lot and they don’t eat much

Question 38

How does gatorade get Na and glucose in the body?

Answer 38

Glucose ocmes in with Na and thiis is what gatorade formula does to provide both at the same time so it goes right into the body, Na binds first so it can bring glucose in

Question 39

What is an alternative to drinking a whole thing of gatorade?

Answer 39

In elite athletes maybe considerate carbs. If you want to use gatorate to make you drink a lottle bit more then you can put a little in the water so you drink more of it. Don’t have to drink it as is. Most kids don’t need it