8+9. adaptations Flashcards
adipose tissue adaptation to exercise
increased mitochondrial content
- same effect across different adipose tissue deposits
markers for mitochondrial content in adipose tissue
COXIV protein content
citrate synthase activity
liver adaptation to exercise
- markers
increased mitochondrial content
markers of this
- cytochrome C content
skeletal muscle adaptation
- obese indv
- 8 weeks
- moderate intensity endurance training
- biopsies
increased
- CPT1 activity
- mitochondrial FA oxidation
CPT-1 role
rate limiting step in FA oxidation
effect of activation AMPK
induces GLUT4 and mitochondrial biogenesis
- protein phosphorylation
effects of HIIT/SIT (sprint interval training) (4)
improves “aerobic” performance
increase mitochondrial enzymes and biogenesis
increase resting glycogen content
increase muscle FA transporters (total GLUT4)
function of citrate synthase
initial enzyme in TCA cycle
- catalyzes acetyl CoA + oxaloacetate = citric acid
HIIT training benefits/negatives
benefits
- improvement seen in 2 weeks
- less time commitment
negatives
- concern with heart patients
- some not enough motivation/skill to perform
- not as many calories burned
time to fatigue associated with
- 2 ways to prevent this
initial muscle glycogen
- increase muscle glycogen stores
- increase muscle ability to oxidize other substrates
glycogen supercomposition
deplete glycogen over a few days with intense exercise, then increase carb intake after
** must deplete first for supercomposition to occur
traditional carb loading technique
Astrand
- exhaustive exercise 7 days before event
- low carb for 3 days following (increases glycogen synthase activity)
- high carb remaining days with minimal training
problems with traditional (Astrand) carbohydrate loading
- training difficult with low carb intake
- irritable
- muscle weakness and disorientation
- exhaustive exercise at beginning have little training effect and can impair muscle glycogen resynthesis
Sherman method of carb loading in comparison to tradition astrand method
more gradual
- limit training 1 week before
- normal diet first 3 days (55% kcal from carb)
- high carb last 4 days (70% carb)
- same muscle glycogen
- better rested
why see weight gain with carb loading
glycogen stores 2.6 grams of water per 1 gram
benefits of high fat, low carb diets
increase capacity for fat oxidation
- increase citrate synthase (CS)
- increase B-hydroxyacyl dehydrogenase
- indicators of mitochondrial content
increase exercise performace
** previously untrained individuals
why untrained benefit from low carb / high fat while trained do not
untrained
- additional stress of low carb
- more endurance gains faster
trained
- high carb able to train harder
carb intake during exercise
- aerobic exercise effects
increase time to exhaustion 30%
- above normal and maintained plasma glucose levels
glycogen resynthesis after exercise
window = 30min to 2hr
4hr post exercise, glycogen synthesis reduced to 50% of capacity compared to right after exercise
- additive effects of insulin
- consume carbs immediately after workout***
effects of high fat diets on exercise performance (trained individuals)
- >45% kcal from fat
- enhances fat oxidation
- increases mitochondrial enzyme activity
- slight reduction in glycogen utilization
- no performance benefit (endurance events)
effects of caffiene on performance
“postulated” increase in fat oxidation and improve endurance performance
*unclear
travel path of caffeine
- quickly enters blood
- crosses all body membranes (including blood brain barrier)
half life of caffeine
4-5hr
how much caffeine is used
5-9mg/kg body mass
ex. 6mg/kg x 70kg = 420mg of caffeine
amount of caffeine in drinks
coffee 16oz grande
- 330mg
redbull 250mL (8oz) - 80mg
original theory to caffeine mechanism of action
- T or F?
stimulates epinephrine release
- increase FFA’s release from adipose
- increase fat oxidation
- spare glycogen, improve endurance
- NOT TRUE*
- when tested, no change in VO2 max, RER or muscle glycogen content
effects of caffiene on exercise
large increase in time to exhaustion
ex. 85% VO2max
recent evidence of the mechanism of caffeine enhances performance
central nervous system
- crosses all membrances including blood brain barrier
- increases arousal, wakefulness, alertnes, vigilance and mood
antagonist to “adenosine”
- binds and blocks adenosine receptors
- adenosine is an inhibitory neurotransmitter
- suppresses arousal and spontaneous activity
caffeine on high power output aerobic performance (20-30 min at 85% VO2max)
- central vs peripheral
large benefit (most studies) - likely central, not peripheral effect
caffeine on intense exercise (4-8min)
- central vs peripheral
central and peripheral benefits
- ion Ca 2+ handling?
caffeine on sprint exercise
- central vs peripheral
no benefit
- purely anaerobic
- single and multiple sprints
side effects of caffeine
anxiety jitters insomnia inability to focus GI upset irritability etc
amount of caffeine on side effects
mild effects
- >6mg/kg body mass
minimal effects
- 3-6mg/kg body mass
*highly variable between individuals
active component of beet root juice
Nitrate (approx 400mg per shot)
- becomes Nitric Oxide
physiological benefit of beet root juice
NO2 = vasodilator
- more blood + oxygen to muscles
- lower oxygen needed
beet root juice experiment
- benefits on exercise
improved time-trial performance and power output
- at multiple power outputs
- O2 consumption lower
- signifcant benefits not seen in elite runners
- genetic variation
- elite runners have higher nitric oxide precursor levels
