232 Hydration
What are the 4 ways in which water is critical for homeostasis?
1. A solvent for biochemical reactions
2. Helps maintain blood volume
3. Transports nutrients/removes waste
- brings waste back to kidneys
4. Used for sweat which cools the body
Are cleansing diets effective?
not really, kidney + liver do a great job of making sure toxins don't build up
Where is water distributed in the body?
Kidneys - 70%
Liver - 70%
Brain - 73%
Bone - 22%
Muscle - 73%
total body - 65%
What are the hydration inputs?
liquid consumption, mostly
Food:
Metabolic processes, lowest contribution
What are the hydration outputs?
Insensible (Ex: sweating)
Respiratory
Urine
Feces/gastrointestinal
What factors can influence insensible outputs?
Wind speed
humidity
sun exposure
- Environmental
degree of physical fitness
clothing
individual sweat rate
What are the 6 factors effecting the need for fluids?
Body comp/size
physical activity
Environmental: heat and altitude
health status
Medications
Some herbal supplements
What is the adequate intake of water for men and women?
2.7L women
3.7L men
- From food and fluids
Describe how caffiene works:
- crosses the blood brain barrier and directly affects the CNS
- "Adenosine receptor antagonist" bonds to adenosine receptors to speed up neural activity
- affects other major neurotransmitters like seratonin for example
How long do the affects of caffiene last?
peak levels are at about 45 minutes after consumption
- half life reported to be between two and 10 hours
How does caffiene affect performance?
inhibits pain receptors; makes exercise less difficult
speeds up neural activity
Why aren't energy drinks reccomended for sport?
- caffiene dose isn't specific which makes manipulation hard
- carbonated drinks can upset the stomach
- contains herbal caffiene ingredients which are not tested
- generally 10-12% carb concentration, not isotonic/hydrating
What are the caffiene reccomendations?
don't exceed 400mg a day
What is the issue with regular caffiene use?
can mask poor nutritional practices, sleep issues and underlying health concerns
What is the caffiene dose ratio for athletes?
3-6mg/kg of bodyweight