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Environmental Influence
on Performance
Sukanya Dandekar (MPT student )
Dr. Suvarna Ganvir (PhD,Prof & H.O.D)
Dept. of Neurophysiotherapy
D.V.V.P.F.s College of Physiotherapy,
Ahmednagar
THERMOREGULATION
Normal body temperature fluctuates
several degrees during the day in response
to physical activity, emotions, and ambient
temperature variation.
A person can tolerate a drop in core
temperature of 18F (10C) but only an
increase of 5C (9F).
Understanding thermoregulation and the
most effective ways to support
temperature control mechanisms can
dramatically reduce heat-related tragedies.
THERMAL BALANCE
heat loss as the body attempts to
maintain thermal neutrality.
This balance results from
integrative mechanisms that
accompllish the following:
1. Alter heat transfer to the
periphery (shell)
2. Regulate evaporative cooling
3. Vary the rate of heat production
Environmental influence on performance
HYPOTHALAMIC REGULATION
OF BODY TEMPERATURE
Central coordinating center for
temperature regulation.
Regulate temperature within a narrow
range of 37C
Temperature-regulating mechanisms
become activated in two ways:
1. Thermal receptors in the skin
provide peripheral input
2. Temperature changes in blood that
perfuses the hypothalamus directly
COLD EXPOSURE
Heat production and heat
conservation occurs
Three integrated factors regulate
body temperature during cold
exposure:
1. Vascular adjustments
2. Muscular adjustments
3. Hormonal adjustments
1. Vascular adjustments:
2. Muscular activity: Shivering,
physical activity generates energy
3. Hormonal output: Increased
release of the epinephrine and
norepinephrine. Prolonged cold
stress also increases release of
thyroxine to elevate resting
metabolism.
HEAT EXPOSURE
Causes heat loss
Integrated factors that regulate
body temperature during heat
exposure:
1. Radiation
2. Conduction
3. Convection
4. Evapouration
Radiation Heat is tranferred from more hot
to less hot
Conduction Direct transfer of heat from skin
surface to air molecules
Convection Air movement replacement of hot air
by cool air
Eg fan
Evapourati
on
Water from resp passages & skin
surface
1 vapourized litre  580Kcal
Sweating : glands secrete hypotonic
solution (NaCl 0.2-0.4%)
Heat Loss in High Humidity
:Sweat evaporation from the skin
depends on three factors:
1. Surface exposed to the
environment
2. Temperature and relative
humidity of ambient air
3. Convective air currents around
the body
EFFECTS OF CLOTHING ON
THERMOREGULATION
Cold :
Air & cloth conduct air poorly
To conserve heat, increase layers
of these
Dry clothing also conserves heat
Warm:
Wet clothing helps heat loss
more than dry clothing
Dry clothing retards heat
exchange
Increasing surface area to the air
also helps heat loss
HEAT STRESS
COLD STRESS :
Altitude
Air density altitude
PO2 of air altitude
O2 loading: ie. Hb saturation with
oxygen
Till 3048m  there is small
change
After that it decreases
ACCLIMATIZATION
Adaptive responses in physiology
& metabolism that improve
tolerance to altitude hypoxia
There are immediate and long-
term adaptations
system immediate Long-term
pulmonary Hyperventilation Hyperventilation
Acid base Alkaline Excretion of base
therefore alkaline
Cardiovascular submax HR
submax Cardiac
Output
Stroke volume
Max cardiac
output
Submax HR
Submax Cardiac
Output
Stroke volume
Max Cardiac
Output
Haematologic Plasma volume
Haematocrit
Hb conc.
No. of RBCs
Local Capillarization of
skeletal ms
RBC
Mitochondria no
Aerobic enzymes
Body wt. & lean
mass
Hyperventilation:
Peripheral chemoreceptors
O2 pressure
Inspiratory activity
Hyperventilation
Acid- base:
Air CO2
Wash out of CO2
PaCO2
Physiologic disequilibrium
pH (loss of H2CO)
Alkaline
Kidneys excrete base HCO3
Restoration of normal pH
No of RBC:
 PO2 Polycythemia
Lactate paradox :
Lactate accumulation reduced
without increase in tissue
oxygenation when hypoxaemia
associated with high altitude should
promote lactate accumulation
 glucose mobilisation from liver
lactate formation
Acclimatization time :
2300m 2weeks
After that every 610m 1
week
Adaptations dissipate within 2-3
weeks after returning to sea
level.
EXERCISE IN THE HEAT
Responses to exercise in heat;
1. Body maintains BP
2. Core temperature & regulated
at high level
3. Water loss: dehydration
Adequate hydration is the key to
maintain all the systems
2 strategies :
Prehydration :
1. 500ml before sleeping
2. 500 ml upon awakening
3. 400-600ml 2o min before exercise
Hydration during exercise:
Prehydration does not replace water loss
during exercise
1. 遜 l  2-3 hrs before exercise
2. 200ml- after warm up
3. 800 ml per hour of exercise
EXERCISE IN THE COLD
Responses to exercise in heat;
1. Body maintains BP
2. Core temperature
3. Water loss : airway moisture loss
 Less physiologic adaptation to
cold than heat exposure
EXERCISE AT HIGH ALTITUDES
Sea level performance does not
affect performance at high level,
vice versa
7 days- intermittent high altitude
exposure increases performance
& induces physiologic exercise
For optimizing performance  
live high , tarin low
Athletes lived at 2500m but
trained at 1000-1250m regularly
They showed greater increase in
Vo2 max and performance than
those who stayed only at 2500m
References
Exercise Physiology.  7 th edition
Victor katch , william Mcardle,
Frank Katch
THANK YOU !!!!!

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Environmental influence on performance

  • 1. Environmental Influence on Performance Sukanya Dandekar (MPT student ) Dr. Suvarna Ganvir (PhD,Prof & H.O.D) Dept. of Neurophysiotherapy D.V.V.P.F.s College of Physiotherapy, Ahmednagar
  • 2. THERMOREGULATION Normal body temperature fluctuates several degrees during the day in response to physical activity, emotions, and ambient temperature variation. A person can tolerate a drop in core temperature of 18F (10C) but only an increase of 5C (9F). Understanding thermoregulation and the most effective ways to support temperature control mechanisms can dramatically reduce heat-related tragedies.
  • 3. THERMAL BALANCE heat loss as the body attempts to maintain thermal neutrality. This balance results from integrative mechanisms that accompllish the following: 1. Alter heat transfer to the periphery (shell) 2. Regulate evaporative cooling 3. Vary the rate of heat production
  • 5. HYPOTHALAMIC REGULATION OF BODY TEMPERATURE Central coordinating center for temperature regulation. Regulate temperature within a narrow range of 37C Temperature-regulating mechanisms become activated in two ways: 1. Thermal receptors in the skin provide peripheral input 2. Temperature changes in blood that perfuses the hypothalamus directly
  • 6. COLD EXPOSURE Heat production and heat conservation occurs Three integrated factors regulate body temperature during cold exposure: 1. Vascular adjustments 2. Muscular adjustments 3. Hormonal adjustments
  • 7. 1. Vascular adjustments: 2. Muscular activity: Shivering, physical activity generates energy 3. Hormonal output: Increased release of the epinephrine and norepinephrine. Prolonged cold stress also increases release of thyroxine to elevate resting metabolism.
  • 8. HEAT EXPOSURE Causes heat loss Integrated factors that regulate body temperature during heat exposure: 1. Radiation 2. Conduction 3. Convection 4. Evapouration
  • 9. Radiation Heat is tranferred from more hot to less hot Conduction Direct transfer of heat from skin surface to air molecules Convection Air movement replacement of hot air by cool air Eg fan Evapourati on Water from resp passages & skin surface 1 vapourized litre 580Kcal Sweating : glands secrete hypotonic solution (NaCl 0.2-0.4%)
  • 10. Heat Loss in High Humidity :Sweat evaporation from the skin depends on three factors: 1. Surface exposed to the environment 2. Temperature and relative humidity of ambient air 3. Convective air currents around the body
  • 11. EFFECTS OF CLOTHING ON THERMOREGULATION Cold : Air & cloth conduct air poorly To conserve heat, increase layers of these Dry clothing also conserves heat
  • 12. Warm: Wet clothing helps heat loss more than dry clothing Dry clothing retards heat exchange Increasing surface area to the air also helps heat loss
  • 15. Altitude Air density altitude PO2 of air altitude O2 loading: ie. Hb saturation with oxygen Till 3048m there is small change After that it decreases
  • 16. ACCLIMATIZATION Adaptive responses in physiology & metabolism that improve tolerance to altitude hypoxia There are immediate and long- term adaptations
  • 17. system immediate Long-term pulmonary Hyperventilation Hyperventilation Acid base Alkaline Excretion of base therefore alkaline Cardiovascular submax HR submax Cardiac Output Stroke volume Max cardiac output Submax HR Submax Cardiac Output Stroke volume Max Cardiac Output Haematologic Plasma volume Haematocrit Hb conc. No. of RBCs Local Capillarization of skeletal ms RBC Mitochondria no Aerobic enzymes Body wt. & lean mass
  • 19. Acid- base: Air CO2 Wash out of CO2 PaCO2 Physiologic disequilibrium pH (loss of H2CO) Alkaline Kidneys excrete base HCO3 Restoration of normal pH
  • 20. No of RBC: PO2 Polycythemia Lactate paradox : Lactate accumulation reduced without increase in tissue oxygenation when hypoxaemia associated with high altitude should promote lactate accumulation glucose mobilisation from liver lactate formation
  • 21. Acclimatization time : 2300m 2weeks After that every 610m 1 week Adaptations dissipate within 2-3 weeks after returning to sea level.
  • 22. EXERCISE IN THE HEAT Responses to exercise in heat; 1. Body maintains BP 2. Core temperature & regulated at high level 3. Water loss: dehydration
  • 23. Adequate hydration is the key to maintain all the systems 2 strategies : Prehydration : 1. 500ml before sleeping 2. 500 ml upon awakening 3. 400-600ml 2o min before exercise Hydration during exercise: Prehydration does not replace water loss during exercise 1. 遜 l 2-3 hrs before exercise 2. 200ml- after warm up 3. 800 ml per hour of exercise
  • 24. EXERCISE IN THE COLD Responses to exercise in heat; 1. Body maintains BP 2. Core temperature 3. Water loss : airway moisture loss Less physiologic adaptation to cold than heat exposure
  • 25. EXERCISE AT HIGH ALTITUDES Sea level performance does not affect performance at high level, vice versa 7 days- intermittent high altitude exposure increases performance & induces physiologic exercise
  • 26. For optimizing performance live high , tarin low Athletes lived at 2500m but trained at 1000-1250m regularly They showed greater increase in Vo2 max and performance than those who stayed only at 2500m
  • 27. References Exercise Physiology. 7 th edition Victor katch , william Mcardle, Frank Katch