Thermoregulation

Question 1

Thermoregulation

Answer 1

Normal body temperatures fluctuate several degrees due to activity, emotions, and ambient temperature variations

Question 2

Thermal balance functions

Answer 2

• Alter heat transfer to periphery to decrease temp
• Regulate evaporating cooling
• Vary rate of heat production

Question 3

Body, core and skin temp

Answer 3

• Body temp: average of skin and internal temperature
• Core temp: internal temperature of body
• Skin temp: heat being released, measurable

Question 4

Hypothalamus’ Regulation of body temp

Answer 4

- Thermostat

- Preoptic anterior portion

- Within a range of 37.0 degrees C +/- 1 degree

- Activated by thermal receptors in skin

- Temp changes in blood that goes through the hypothalamus

- Critical limit - 41 degrees C

Question 5

Heat exchange

Answer 5

1. Radiation: sun

2. Conduction: heat transfer through touch

3. Convection: heat transfer through air flow

4. Evaporation: cooling when sweat evaporates

Question 6

Clothing and thermoregulation

Answer 6

• Cold weather - clothes that allow for water vapor (sweat) to escape or absorb - blocks air movement
• Warm weather - dry clothing retards heat exchange more than soaking wet - football gear is a huge barrier to heat dissipation

Question 7

Water loss

Answer 7

• For an acclimatized person, sweat loss peaks at 3L/hr
• Durng intense exercise in the heat, 12L on a daily basis
• Climatized = more sweat and sooner
• Sweat gland fatigue = imparied core temp regulation
• Hot and humid environment - impedes sweating and fluid loss

Question 8

Dehydration

Answer 8

• Impairs thermoregulation
• Decrease in plasma volume decreases sweating
• Premature fatigue
• Decreased plasma volume increases HR, increases perception of effort

Question 9

3 factors that sweat evaporation depend on

Answer 9

1. Surface exposed to the environment
2. Temperature and relative humidity of ambient air
3. Convective air currents around the body

Question 10

Heat dissipating mechanisms

Answer 10

1. Circulation - peripheral blood shunting
2. Evaporation - sweating
3. Hormonal - conserve electrolytes and fluid

Question 11

4 factors that affect sweat loss

Answer 11

1. Intensity

2. Duration

3. Temperature

4. Humidity

Question 13

Factors affecting heat tolerance

Answer 13

1. Acclimimatization: increases capacity for exercise with less discomfort
2. Exercise training: increases sweating sensitivity to lower core temp sooner
3. Age: older adults cant recover because they dont have a good thirst mechanism and kids need longer to acclimate because they dont sweat as much