Adjustment to exercise and regulation of food uptake Flashcards
How does pulmonary ventilation change with strenuous exercise relative to light?
no true plateau phase in heavy exercise
What is VO2 max used for?
estimation of cardiac output due to the close association
how does execise affect this?
oxygen extraction by muscle improves with exercise training due to increase capillarization of muscle fibers, increased mitochondria and increased aerobic enzymes
What is the ventilatory breakpoint? What causes it?
point during progressively increasing exercise intensity at which VE increases disproportionately to VO2; buffering of lactic acid increases CO2 levels which triggers the increase in VE
How is the lactate threshold found?
VE/VO2 and VE/VCO2 can be used to estimate it
What affect does training have on lactate levels during exercise?
decreases the rate of accumulation of lactate
What affect can respiratory muscles have during acute exercise?
15% of O2 consumed during heavy exercise; typically does not limit performance but can in highly trained individuals
What are respiratory adaptations to training?
tidal volume increases only during exercise, rate stays steady at rest, decreases with submaximal exercise and can increase dramatically with maximal exercise; VE increases during maximal effort after training; pulm diffusion increases at maximal work rates, a-VO2 difference increases with training due to increased extraction
what are the metabolic adptations to exercise?
improved submaximal aerobic endurance and max O2 consumption, improved blood and oxygen supply to working muscles, improved efficiency of energy production
What factors affect VO2 max?
level of conditioning (max within 8-18mo of heavy endurance training), heredity, age (decrease with age), gender- lower in women 20-25% in untrained and 10% in trained, and specificity of training
what happens to blood lactate levels due to training? why?
decrease in concentration, change of fast twitch glycolytic fibers to fast-twitch oxidative, increase in capillaries to muscles, increased myoglobin content, increase number and size of mitochondria, store more glycogen and triglyceride, increased triglyceride store increases use as a fuel and decreases lactate prod
What is hitting the wall?
run out of glycogen in the muscles; body typically tries to spare glycogen stores; why athletes supplement with glucose goo and sugary sports drinks
what is QO2?
maximal respiratory or oxidative capacity of muscle
What affect does training have on enzymes in the muscles? QO2?
increase in enzymes, increase in their activity, increase in QO2
What adaptations to training affect energy sources?
store more glycogen and triglycerides, FFAs better mobilized and more accessible, ability to oxidize fat increases
What happens to blood volume due to training?
increased blood volume due to increased plasma volume (increases ADH, aldosterone, and plasma proteins cause more fluid to be retained in the blood) RBC volume increases but hematocrit decreases (plasma increase greater), viscosity decreases, improving circulation and enhancing O2 delivery
What factors contribute to body heat lost?
radiation, conduction convection, evaporation (can be a method of gaining heat in certain circumstances)
What factors contribute to the gain of body heat?
metabolic heat and environmental heat
What is the main method of heat loss at rest? exercise?
radiation; evaporation
How do muscles adapt to increase in heat in the muscle?
increase heat shock proteins
What happens if body heat increases above 40? 41-42?
affect NS and reduce ability to thermoregulate; sensitive organs can be damaged-> GI and kidneys most sensitive; with heat stroke can develop sepsis 24-48 hours later due to GI break down and leak