This document discusses how environmental factors like temperature, altitude and humidity can influence human performance. It covers the body's thermoregulation processes for maintaining core temperature during cold and heat exposure. During cold, the body increases heat production and conservation through vascular, muscular and hormonal adjustments. During heat, the main mechanisms of heat loss are radiation, conduction, convection and evaporation. Acclimatization to altitude involves both immediate and long-term adaptations to the reduced oxygen levels to improve tolerance. The key factors for exercising in heat and cold are maintaining hydration and avoiding large fluctuations in core temperature.

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

13. HEAT STRESS

14. COLD STRESS :

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

18. Hyperventilation:
Peripheral chemoreceptors
O2 pressure
Inspiratory activity
Hyperventilation

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. ½ 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

28. THANK YOU !!!!!