asynchronous lectures Flashcards
how does the body lose heat to cool down
vasodilation and sweating
how does the body decrease heat loss to warm up
vasoconstriction and shivering
who was alberto salazar and what was his importance
won a bunch of marathons in the 1980s and recorded the highest water loss during a marathon which was 3.7 L/Hr
4 ways heat is transferred
- radiation: radiated from a hot object to cooler object
- conduction: direct contact with something
- convection: air or water moves across our skin to make us feel warmer or cooler
- evaporation: sweating which makes the skin feel cooler as the process is occurring
what is the skins physiological response to heat
sweat glands secrete sweat to cool the skin
what is the cardiovascular systems physiological response to heat
blood vessels dilate, which dissipates heat to the environment
what is the urinary systems physiological response to heat
kidneys retain water to offset water loss
what is the endocrine systems physiological response to heat
fluid electrolyte hormones retain water and NaCl via the kidneys to offset sweat losses
strategy for acclimatization
- spend more than 14 days exercising in the heat
- options are to do less than 50% VO2 max for 90-100 min a day OR up to 70% VO2 max for 50-60 min a day
what are some early adaptations to acclimatization (6)
- improved cardiovascular function
- expanded plasma volume
- ADH: retain body water
- aldosterone: retain salt
- decrease heart rate
- redirection of cardiac output to skin and muscle
long lasting adaptations of acclimatization (4)
- increased sweat sensitivity
- decreased electrolytes in sweat
- decreased skin blood flow
- decreased competition between muscle and skin
peripheral chemoreceptors are located in the…
aorta and carotid arteries
phases of integrated regulation during exercise
PHASE 1: stimuli from cortex increases respiration
PHASE 2: after 20 seconds ventilation increases to reach steady state
PHASE 3: fine tuning of steady state ventilation through peripheral sensory feedback mechanisms
what is the onset of blood lactation accumulation
the point where VO2 is at the highest point without the increased blood lactate level
this point is at 4.0 mM/L
what is a normal value for the ventilatory equivalent
approx. 25 in adults
exercising in the cold depends mostly on
maintaining warm body
preventing local cold injury
nervous system response to exercise in the cold
sends efferent messages that maintain/alter body temperature and regulate cutaneous blood vessel responses
muscular system response to exercise in the cold
shivering produces internal metabolic heat
endocrine system response to exercise in the cold
fluid-electrolyte hormones retain water and NaCl via the kidneys to offset dehydration
cardiovascular system response to exercise in the cold
cutaneous blood vessels constrict, this retains heat in the body and maintains central blood volume and pressure
what is shivering
rapid oscillation which is used to produce heat
we can produce 100 watts of heat at rest to maintain internal temperature
Dr G has ___ numb fingertips from non freezing cold injury
8
Health risks from the cold
- frostbite
- hypothermia
- non-freezing cold injury
key to cold performance
gradual, increased exposure and insulation
cold induced vasodilation
increases in temperature and periodic warming of the fingers is because the body will vasodilate to hopefully prevent the loss of the fingers
habituation
decreased response to repeated stimulus, less vasoconstriction, more blood flow/heat delivery to peripheral tissues
exercising at altitude depends mostly on
improving blood oxygenation
preventing hypoxia-related mountain illnesses
hypoxia
low oxygen in the blood
nervous system response to exercising at altitude
sends efferent messages that maintain/alter blood gas and acid-base balance
endocrine system response to exercising at altitude
fluid-electrolyte hormones retain water and NaCl via the kidneys to offset dehydration
respiratory system response to exercising at altitude
VO2 max decreases
cardiovascular system response to exercising at altitude
oxygen carrying capacity of the blood increases, cardiac muscle mass increases, chemoreceptor sensitivity increases
muscular system response to exercising at altitude
respiratory muscles adapt to hypobaria, myoglobin levels in muscle increase
urinary system response to exercising at altitude
kidneys retain water and NaCl to offset dehydration
skeletal system response to exercising at altitude
red blood cell production increases in bone marrow
medical conditions associated with altitude
- acute mountain sickness
- high altitude cerebral edema
- high altitude pulmonary edema
- high altitude flatus explusion
strategies to perform at altitude
- train at altitude
- train low, sleep high
- climb high, sleep low
exercise at depth depends on
filling lung with air
preventing hypobaric injury
endocrine system response to exercise in hyperbaria
conserve the freaking water ->ALWAYs
cardiovascular system response to exercise in hyperbaria
pressure and volume receptors respond to underwater depths by altering blood pressure, heart rate, and cardiac output
urinary system response to exercise in hyperbaria
kidneys are involved in fluid-electrolyte homeostasis
breathing is stimulated by high ______ not low _____
blood CO2 & blood O2
hyperventilation decreases blood ____
CO2
what is decompression sickness
occurs from rapid ascent when nitrogen does not have time to be expired from lungs and instead is dissolved into blood
how to train in heat
establish high level of aerobic fitness, acclimatize, HYDRATE
how to train in cold
habituate (gradual increase), build up insulation (swimming), mission specific clothing
how to train for altitude
gradual acclimatization, climb high, sleep low, progression
Rule of 5s (6 points)
- total lung capacity 5L (male)
- total blood volume 5L (male)
- resting cardiac output 5L/min (male)
- resting a-vo2 difference 5ml O2/100 ml blood
- difference between FIO2 and FEO2 air at rest 0.5 of 5%
- caloric equivalent for oxygen 5 kcal/L O2
