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final exam: chapter 12&24- exercise and environment

Terms in this set (72)

as we increase altitude, what happens to barometric pressure?
it decreases leading to less pO2
as we increase altitude, what happens to sweating?
sweating increases because at higher altitudes there are colder/dryer temperatures so we lose more water
as we increase altitude, what occurs with radiation?
we have increased exposure to sun radiation since we are closer to sun
the higher the altitude, the ___ oxygen delivery
less
the lower the altitude, the ___ oxygen delivery
more
there is less o2 in the blood at
increased altitudes
as we increase altitude, ventilation
increases
how does our body know we need to breathe more at increased altitudes?
via chemoreceptors telling our respiratory cc
what are 3 physiological responses to altitude?
1. increased Hb
2. CHO metabolism becomes preferred
3. leftward shift of oxyhemoglobin curve
explain why Hb increases as we increase altitude
when we increase altitude, our blood volume viscosity becomes thicker meaning an increase in Hb. this is due to dehydration
explain why CHO metabolism is preferred as we increase altitude
as we increase altitude, there is less oxygen present (less aerobic metabolism) so we rely on CHO and anaerobic metabolism to give us energy
explain why there is a leftward shift of oxyhemoglobin curve as we increase altitude
as altitude increases, it promotes the binding of Hb to O2. at lower PO2, there is a tighter binding of Hb to O2
how does increased altitude affect short term anaerobic performance (sprinting)?
less resistance and thinner air can lead to improved performance (no effect can also occur)
how does increased altitude affect long term aerobic performance (distance running)?
- distance running performances are adversely affected at altitude due to a decrease in VO2 max
- due to less o2 delivered to muscles, performance decreases
as our body adapts to high altitude, what happens to RBC?
there is an increase in RBC production which leads to an increase Hb which increases blood volume
increase in RBC production
polycythemia
when our body adapts to high altitudes, what protein is produced?
hypoxia inducible factor (HIF1)
when hypoxia inducible factor (HIF1) is released, what other things does it promote to be released?
- erythropoietin, vascular endothelial growth factor (VEGF), and nitric oxide synthase
tells bone marrow to create more RBC
erythropoietin (EPO)
promotes production of RBC
vascular endothelial growth factor (VEGF)
enzyme that promotes production of nitric oxide that increases vasodilation of muscles so more o2 can be delivered to them
nitric oxide synthase
when our body adapts to high altitudes, there is greater oxygen saturation due to what?
increased blood flow to the lungs from an increase in nitric oxide
as altitude increases, plasma volume
increases
as altitude increases, capillary density to skeletal muscle
increases
as altitude increases, muscle mass
decreases
in what ways do we measure our temperature?
- deep body (measured at rectum, ear, or esophagus)
- skin
as body temp increases, performance
decreases
what are 2 ways we can generate heat?
1. voluntarily through exercise
2. involuntary through shivering or non shivering thermogenesis
what are the steps in which heat is produced through non shivering thermogenesis?
1. hypothalamus senses change in body temp
2. sends signal to the pituitary gland who sends signal to the thyroid gland
3. the thyroid gland releases thyroxine and catecholamines (epi). these both increase metabolism which increases heat
- electromagnetic radiation transfers heat between two surfaces
- no physical contact
- heat from sun to ground/us
radiation
transfer of heat between 2 surfaces that are in contact
conduction
heat transferred to air or water
convection
heat from skin converts water (sweat) to water vapor
evaportation
what 2 heat exchange mechanisms go hand in hand?
convection and evaporation
what is the number one form of heat exchange during exercise?
evaporation
as we exercise and room temperatures increase, what happens to convection and radiative heat loss?
they decrease. the closer the temp gradient of the room (air) and person (body), the less heat loss from convection/radiation occurs
when we exercise in a hot environment we have the inability to lose heat. why is this?
- higher sweat rate
- the more we sweat, the less blood volume we have ultimately decreasing our cardiac output
why does CO decrease when we exercise in a hot enviornemnt?
increased sweating leads to decreased blood volume which leads to decrease SV and ultimately decreased CO
why does SV not increase in a hot enviornment?
due to a decrease in blood volume from sweating
what compensates for the decrease in SV?
increased HR (cardiovascular drift)
what can severe dehydration lead to?
an onset of heat related illnesses
how is exercise impaired in a hot environment?
- heat related muscle fatigue
- rely on glycogen metabolism
- increase in free radical production
- decrease muscle blood flow
- increase in brain temperatures
how does relying on glycolysis impair performance in a hot environment?
- it increases our lactate accumulation meaning we will reach fatigue quicker than if we exercised in cooler temps.
- we also rely on carbs
how does increase in free radical production impair performance in a hot environment?
- free radicals are stimulated when we exercise in a hot environment and it inhibits the binding of actin and myosin
- inhibits muscle contraction
- results in damage to actin and myosin (muscle contractile proteins)
how does decrease in muscle blood flow impair performance in a hot environment?
less blood is going to the muscles and instead more blood is going to the skin to promote sweating so we can cool down (during high intensity exercise)
how does increase in brain temps impair performance in a hot environment?
- high brain temps reduces neuromuscular/central command drive meaning we have less of a drive to win
- reduction in motor unit recruitment
rapid adaptation
acclimation
what are the main factors that become acclimatized when we exercise in a hot enviornemnt?
- increase in plasma volume
- sweat earlier on in workout (helps keep body temp down)
- higher sweat rate
- reduced sodium chloride loss in sweat (reduce risk of electrolyte disturbance)
- less blood flow to skin and more to muscles (other adaptations promote sweating to keep skin cool)
- increased cellular heat shock proteins (help protect muscle contraction protein cells from destruction)
one acclimatization to exercising in a hot environment is an increase in plasma volume. what does this promote?
- prevent na+ loss
- optimized evaporation heat loss
- sweat rate, distribution, and content change/increase
- lower core temps during exercise
the more we sweat...
cooler our core body temp is
in an acclimated individual who exercise in hot environment, what two things decrease?
HR and body core temp
what is the main heat release mechanism when exercising in the heat?
evaporation
what happens to cardiac output when exercising in the heat?
it is maintained due to cardiovascular drift
name 3 ways that exercise performance decreases when exercising in the heat
1. increase in free radical
2. decrease in muscle blood flow
3. rely on glycolysis
how do athletes physiologically adapt to heat?
increase in plasma volume
how would you recommend your athlete to adapt to the heat?
stay hydrated
what is the body's physiological response to exercise in cold environment (hypothalamus)?
1. skin and core receptors send signal to hyp. they are cold
2. hyp. senses change in temperature and sends signal to pit.
3. pit sends a signal to the thyroid
4. thyroid releases thyroxine (increase met.) and catecholamines (epi promotes vasoconstriction)
5. shivering and cutaneous vasoconstriction also occur (less blood flow to muscles and skin and more to organs)
stimulated from SNS and promotes release of epi to promote vasoconstriction of blood vessels
catecholamine
air movement, not air temp
wind chill
wind chill is equivalent to what heat loss mechanism?
convection
in what 2 ways does body comp. affect heat loss?
- increase in peripheral muscle= increase insulation
- increase in subcutaneous fat= increase insulation
what are the cardiorespiratory effects of exercise in the cold?
- lower core temp= slower HR and decrease in ventilation (help conserve energy)
- decrease ventilation
- decrease blood flow to skin and muscle (due to vasoconstriction)
what effect does the cold have on the skeletal muscle?
as our core body temp decreases, the blood flow to the muscles decreases leading to a decrease in force production
exercising in the cold can lead to fatigue leading to....
decrease in heat production
as fatigue increase, heat production
decreases
what is a result of a decrease in heat production due to fatigue?
- hypothermia
- loss of judgement
- reduced dexterity in extremities (due to reduced blood flow and slower nerve transmission)
- risk of frostbite
what can athletes do to stay warm in a cold enviornement?
- wear jacket with battery packed electric currents
- extend their warmups
- eat more carbs
- wear face masks
the partial pressure of inspired oxygen (PO2) decreases with increasing altitude because of the
low barometric pressure
natives whoo have resided at high altitude all their lives adapt to the altitude by
producing more RBC
the transfer of heat from the body into molecules of cooler objects with its surface is called
conduction
When track meets are held at altitude, the sprint performances are usually better than at sea level because of the
lower air density
What are the acclimizations the body undergoes at increased altitudes?
1. increase RBC
2. Increase oxygen concentration
3. Increase capillary density
4. Increase plasma volume
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