ENVIRONMENTAL EXERCISE PHYSIOLOGY Flashcards
(73 cards)
1
Q
Why do fitter people experience more heat stress
A
because they can workout harder
2
Q
What is the number 1 and 2 cause of heat stress
A
- exercise
- environment
3
Q
Muscle Warmups
A
muscles can warm rapidly by 2-3 degrees in endurance and resistance exercise. you can warm them up fast, and warm muscles produce more more power
4
Q
Hot Muscles
A
produces a greater force/power but they fatigue faster
5
Q
What 4 things effect muscle temperature
A
time
intensity
clothing
air temperature
6
Q
Intervals and Endurance with heat stress
A
intervals - increase heat stress more than you thin
endurance - hotter environments have a small effect but nothing crazy
7
Q
Hot environments and endurance performance
A
muscles are benefited when warm, but endurance performance is usually benefitted in cool environment
the optimal temperature is much cooler than when resting
but the impact is not as big as you would think
8
Q
What does exercise optimal temperature depend on
A
- humidity
- exercise intensity
- clothing
- body composition
- body size
- exercise mode
- the fitter you are the better you adapt to heat stress
9
Q
What is the problem with heat
A
- thermoregulation reduces exercise capacity
- thermoregulatory power is finite and limited by other effects of exercise on the body
- heat stroke can be fatal
10
Q
Maintaining Heat Balance
A
37 - resting zone
38 - some limited to here
39 - where most people fatigue
40 - limit for most athletes
42 - some can tolerate at this level
11
Q
What determines body temperature in exercise
A
the receptors increase blood flow or sweat
it is determined by ones -
initial status - body temp, composition, menstrual cycle ect
heat production - duration, pattern of exercise, efficiency
heat loss - environment, clothing, sweating
12
Q
What senses body temprature
A
mainly the hypothalamus but also spinal cord, skin and the stomach
13
Q
Heat gain and loss need to …
A
match to keep exercising
14
Q
What things cause heat gain
A
- radiation
- convection
- conduction
15
Q
What things cause heat loss
A
- evaporation
- radiation
- convection
- conduction
16
Q
what % of energy release is wasted as heat
A
70-100% on 0-25% for work
17
Q
Heat production =
A
metabolic rate - work rate
- they are directly related
- similar for all limbs
18
Q
Environment effects
A
capacity of the environment to absorb heat is many factors but what has the biggest impact is the water vapour pressure, how much water is in the air, the humidity
70% determined by humidity only 10% by temperature
this can be represented by a wet bulb glove temperature
hot and humid = stressful environment
19
Q
3 big physiological demand of exercise
A
- increase muscle blood flow
- increase skin blood flow and sweating
- need to maintain arterial pressure and blood supply to other tissues
20
Q
Physiology of exercise in heat
A
- warmer periphery (skin)
- increase skin blood flow and sweating
- decrease in blood volume so increase HR to pump heart more and SV decreases
- increase in stress hormones which use more glycogen so
- increase in muscle glycogen depletion
- increase in lactate, perceived effort and thermal discomfort
21
Q
Sweating
A
is extremely important to offload heat and sustain exercise
this require evaporation, which humans have the unique ability to do but sweat causes dehydration leading to decrease in heat loss and exercise tolerance
22
Q
What Limits Performance under heat stress
A
- critical body core temperature (38 or 40 if athlete)
- rate of body warming
- cardiovascular strain
decreases BP so HR increase and VO2 max decreases - psychophysical strain - RPE
- metabolic strain
glycogen depletion
23
Q
Major personal factors governing performance in heat
A
- aerobic fitness - explains 1/2 of variability to exercise heat tolerance, rise in core temperature
- heat acclimatisation - fitness level impacts this
- initial physiological status eg. thermal temp when you start
- hydration, low body water impairs many things
others
- recent illness - massive impact - don’t go under heat stress if had a recent fever
- medications
- age
- sex
- sleep
- motivation
- body size
24
Q
Stratergies to decrease heat strain and increase performance
A
- increase aerobic fitness (get fitter) and heat acclimatisation
- decrease clothing and carried weight
- decrease exercise volume
- optimise plasma volume and osmolality eg. drink water/training status
- artificial cooling - before - during - rest periods - slushies are excellent but ice vests are less effective
24
Heat Related Illnesses
- sunburn (impairs sweat and blood flow and you need both these for heat loss)
- heat cramps
- heat syncope
- heat exhaustion
- exertional heat stroke
25
Heat Related Illnesses - heat syncope
this is fainting, especially during the 1st day of exercise in the heat
caused by inadequate vasoconstriction and a HR response to maintain BP
26
Heat Related Illnesses - heat exhaustion
rapid HR, hot, flush, exhaustion, sweaty
caused by homeostatic capacity exceeded
27
Heat Related Illnesses - exertional heat stroke
this is complete exhaustion with CNS disturbance
caused by major cellular disturbance, mainly due to a crazy increase in body temperature
- this is a medical emergency
28
How many days to get heat benefits
only takes a first few days, but for sweating ability then a couple weeks is better
29
acclimation
- fake heat, but just as good
30
People that are really competitive but have low cardiovascular ability
are more likely to get these heat related illnesses
31
Heat related illnesses often happen
- early in the summer before your adapt
- unseasonably warm
- clothing
- least fit people in team training frills
- recent illness
32
Cold, Wet and Wind Cause
cold decrease leading to a decrease in body temperature which then goes on to impact
- a decrease in power and strength
- fatigue (energy depletion)
these and directly leading to decreasing exercise temperature
33
What issues arise from cold stress for exercise
- impaired performance
- discomfort
- glycogen depletion
- injury
- illness
- hypocapnia
34
optimal environment for exercise is cooler than at
rest and more so as exercise intensity increases
35
Effectiveness of Behavioural responses to cold
behaviour is the most powerful response
except when
- cognitively impaired my hypothermia (percievement of cold)
- injured
- cold impaired strength, coordination etc
- competitive exercise behaviours and choices
36
Physiological responses to cold stress
1. vasoconstriction
2. shivering
3. counter current heat exchange in limbs
4. non-shivering thermogenesis
37
Physiological responses to cold stress: Vasoconstriction
of the skin and muscle allowing both of them to be insulators
38
Physiological responses to cold stress: shivering
this is an ok process but it affects other processes
- in water movement increases heat loss
- dilated blood vessels in muscles decreasing their insulation
39
Water Membrane and Shivering
the body is protected from the water by a membrane but when we move this breaks the layer adding to the cold stress
40
skin temp will drop to protect the
core temp with progressive consequences
41
Temperatures
33 = resting comfort
here this is when cooling responses occur
15 = onset of pain
-5--8 = skin freezers
42
Core Temp effects
37 = resting
36 = moderate shivering
35 = hypothermia
33 = CVD
29 = becomes fatal
43
How does cooling impacts effect exercise variables
decrease in peripheral temperature and their sensory and motor functions
skin temp is governed by the environment but hands and feet are on their own
increases metabolic rate, increasing energy consumption and fatigue and decreases shivering efficiency
44
Fit vs Fat People
fit can shiver more and are better at producing heat
fat have good insulation, more body mass so reduces the loss of heat, but can't shiver as much
45
Worst people at responding to heat stress
low fat and peptite people
46
Humans do not adapt cold defence with repeated cold stress instead we cool
faster whilst feeling more comfortable
47
Unacclimatised vs Acclimatised People Responses
UN - core temp drops and shivering increases more
AA - less and shorter shivering but
48
Specific Hazards with Cold: Immersion into Water
water conducts heat 25x faster than air and also increase convection greatly
1. cold shock response
this is your initial gasp, rapid and long lived
2. Incapacitation
strain on the heart, hard to breathe, muscle coordination
3. autonomic conflict
diving response
49
Exercise in Cool and Cold Water
good or bad on water temp
under 10 is bad 28 is beneficial
- the body insulation degraded
- boundary layer of water is broken
50
What could be fatal swimming
swimming in cool, fast and intense swimming
51
do females or males have better distribution of more fat
females
52
Specific Hazards with Cold: Prior to Exercise/Heat Stress
- higher core temp when getting into water = rapider decrease in core body temp
- can decrease energy capacity due to decrease insulative capacity
53
Hypothermia
does not usually develop as quickly as you might expect
symptom varies
prevention is key
54
Treatment of Hypothermia
to prevent further cooling, remove wet clothes have dry skin
warm core and torso first
may get worse before it gets better
55
What are the stressors of a higher altitude environment
- decrease in O2 pressure
- decrease in temp
- decreases in humidity
- decreases in liquid water
- increase wind
- increase UV radiation
56
What physical effects does the high altitude stressors lead too
- increased ventilation, glycolysis and energy usage, and catabolism
- decreased fluid and energy intake and gut absorption
57
What are the potential results of the high altitude stressors and physical effect
the hypos
58
What do all the stressors, potentials results and physical effects of a high altitude, lead to in terms of practical and performance effects
- decreased VO2 max and anaerobic threshold so decreases training intensity
- increase in CHO needs but a decrease in appetite
- psych stress, boredom, decrease sleep, decrease cognitive factors
59
Altitude M and effect on Aerobic power
0-1500m there is no effect
after every 100m after this these is a 1% decrease in aerobic power due to a lack of O2 which decreases max CO
60
Who are the people most effected by Altitude
aerobically fit as a low O2 pressure impacts them more but they still have higher capacities to survive and move
61
How are sports affects
high altitude = low air pressure and low gravitational force, so air related sports are benefited like long jump.
teams sports it depends on all the individuals so hard to tell.
62
Acute Responses to High Altitudes
these are cardiorespiratory
there is an increase in HR and ventilation at rest and submax exercise
they then being to increase haematocrit as fluid is lost
blood gets thicker and more conc of rbc which happens when fluid is lost so overall increase rbc saturation in the blood
63
Adaptive Responses to Altitude
largely related to individual differences eg. genetics
successful adaption must be graded
64
Summary of Acute Responses to High Altitude
the 1st response is to hyperventilate to breathe more as their is low O2 pressure
We have high O2 Arterial Pressure so we are making more CO2 than we can get out
therefore we have to much bicarb making our blood to basic so buffering occurs to get it back to th optimal pH. the kidneys do this my ditching the bicarb and getting ride of a greater volume.
This then decreases SV and increases HR and the buffering also leads to the increase the O2 delivery to tissues
65
Long Term Responses to High Altitudes: Cardiovascular
Pressure volume still decreases so our SV and HR also decrease to your aerobic power also decreases
to counter this we increase our EPO which stimulates the increase of making more rbc to store for aerobic power - this is the reasons athletes train at high altitudes
66
Long Term Responses to High Altitudes: Muscle
increase mitochondria density, capillarisation and aerobic enzymes, not all proven
67
Medical Problem - Acute Mountain Sickness
this is very common in the first few hours and days when up 3000m
- it is directly related to how fast and how high you go up, partly genetics.
- less common is females
- aerobic fitness won't help
often caused by some brain swelling
can be prevent ed by having a gradual ascent, high carb diet and drugs
treatment is time, drugs and oxygen/descent is severe
68
Medical Problem - High Altitude Cerebral Oedema
this is not common, but is fatal if untreated
symptoms and prevention are the same as AMS
69
Medical Problem - High Altitude Pulmonary Oedema
this is not common, but is fatal if untreated
symptoms - more fatigue, chest pain, dry and is caused by hypertension and oxidative stress
prevention is unclear but treatment is through assisted descent
70
Preparing for exercise/PA at altitude
climbing over 6000m - cyclic exposure, repeatedly increase altitude, work high, sleep low
trekking 2500-5000m - if arrive by plane don't overdo exercise
competition - 2100-2500m for 2 weeks them as you increase altitude you need to decrease training intensity
71
Is Altitude Training worth is for Sea Level Performance
depends on the individual
most peoples threshold for EPO is at around 2150-2450m
optimal method may be
live high, train high and low
72
