Intro Flashcards
according to a recent study, about how many people get less than 3000 steps per day
16%
What is the current lowest percent of obesity in a state and the highest?
20-24%
>35%
What are the functional requirements for community living? (5)
- perform/tolerate postural transitions
- ambulate >= 150’
- ambulate at a rate of 1.3m/s+
- carry 6.7 lbs
- accommodate various environments, obstacles, surfaces, terrains, and slopes
What are the predictors of successful aging? (7)
- physical function (ADL’s)
- presence of comorbidities
- smoking status
- global cognitive scale
- systolic BP
- depression
- personality traits
Def: Metabolism
the sum of all chemical reactions that occur in a living organism
Def: Bioenergetics
the transfer and utilization of energy in biological systems
Laws of Thermodynamics
1) Energy is neither created or destroyed
2) All processes move from an ordered to disordered state
what is the application of law of thermo #1
Energy (food) = Energy out (work) + energy out (heat) +- energy stored (fat)
what is the application of the law of thermo #2?
randomness increases
60-70% energy lost as heat
remaining energy used for mus activity and cellular processes
Gibbs Free Energy
- chemical rxns spontaneously proceed in an energy favorable direction (G
Gibbs free energy of most biological systems
unfavorable, G>0
how ATP transfers energy from energy yielding catabolic processes to energy requiring rxns
What is mostly used at rest for energy
fat and carbs
Facts of Carbs
readily available and easily metabolized
Pathway of Carbs
ingested -> converted to glucose -> taken up by liver and muscles -> converted to glycogen
where is glycogen stored
liver
Glycogen Advantages (5)
- higher energy yield per liter O2 (5.1kcal/LO2)
- anaerobic and aerobic
- rapid pathway
- stores can be greatly increased by training and diet
- can provide sole energy during heavy exercise
Glycogen Disadvantages (3)
- stored in relatively small amounts, w/ H20
- anaerobic - lactate accumulation
- muscle cells are dependent on internal glycogen stores => once depleted, mod intensity cant continue
Fat energy
provides substantial energy during prolonged, low intensities
larger reserves
how is fat stored
stored glycerol and free fatty acids, which less accessible for use from atp
only FFAs used to form ATP
most fatty acids that are important for human energy during exercise have 12-18 carbons
intramuscular triglycerides 100-240 mmol/kg body weight
Fat Advantage (3)
- greatest value for fuel (9.3kcal/g)
- can be stored in large amounts
- stable energy source that can be mobilized for use during exercise
Fat Disadvantage (5)
- total caloric value of intramuscular lipid is small compared to glycogen
- only aerobic
- oxidation yields less energy/liter of O2 consumed (4.62kcal)
- majority fat is stored outside of mus tissue
- cannot serve as sole energy source
Carbs vs Fat
1g carb => 17KJ/4kcal energy
1g fat => 37KJ/9kcal energy
for every 1 g of glycogen, how much H2O is stored
2.7g
Protein
energy by glucogenesis (in liver)
- can generate FFAs in times of starvation through lipogenesis
- only basic proteins (amino acids) can be used for energy, nitrogen cannot be oxidized
- ~20% human body is protein => potential energy of 52000kcals
Theoretical Time to Exhaustion
for every 1 g O2 consumed, how much energy burned
5kcal energy burned
Theoretical Time to Exhaustion
Carbs
TOTAL = 10MJ of energy
(Mus: 500g - 8.4MJ - 2000kcal)
(Liver: 100g - 1.7MJ - 400kcal)
how long can carbs sustain energy output at 3.0L/min (70% VO2max)?
2-2.5 hours
Theoretical Time to Exhaustion
Fat
TOTAL = 308MJ of energy
(Mus: 500g - 8.4MJ - 2000kcal)
(Adipose: 200g - 7.5MJ - 1800kcal)
how long can fats sustain energy output at 3.0L/min (70% VO2max)?
3-5 days
Theoretical Time to Exhaustion
Protein
TOTAL = 234MJ of energy
Mus: 14kg - 234MJ - 52000kcal
how long can proteins sustain energy output at 3.0L/min (70% VO2max)?
2.5 days
