09 Heat Stress...

Question 1

It is important that body temp is maintained within approx. _________ of each person’s normal value because larger deviations dramatically affect biological function.

Answer 1

1.5 degrees

Question 2

Body can transfer heat to and from the surroundings through:

Answer 2

1. Evaporation
2. Radiation
3. Conduction
4. Convection

Question 3

Two physiological processes our bodies use to transfer heat and maintain thermal balance

Answer 3

1. Increasing blood flow to the surface of the body (skin) so heat can mostly be lost through radiation and convection along with conduction
2. Evaporative cooling that occurs when sweat is evaporated from the skin

Question 4

The Magnitude of the increase in core temperature depends on (Three Major Factors Contributing To Increased Body Temp)

Answer 4

1. Physical work performed
2. PPE worn
3. Ambient temp

Question 5

Changes in core temp depend on:

Answer 5

1. Physical work
2. Length of time spent working
3. number of evolutions (training)
4. Time of rehab or recovery between each evolution
5. How recovery time was used

Question 6

PPE adds to heat gain because:

Answer 6

1. It is heavy (50-70 pounds)
2. Movement requires greater metabolic/musculara work
3. Interfering with heat dissipation (insulative)

Question 7

What is essential for proper cooling and physiological recovery?

Answer 7

Removal of PPE

Question 8

Ambient Conditions that can contribute to increased body temperatures:

Answer 8

1. Air temp
2. Relative humidity
3. Sun exposure
4. Wind speed

Question 9

Core temps were found to increase by:

Answer 9

1. Over 3 degrees for FF conducting overhaul and outside vent ops (16-19 minutes)
2. Approx. 2 degrees during fire attack and search and rescue tasks (10-11 minutes)

Question 10

Working in hot and humid conditions can lead to fluid loss of _________ per hour from sweating and firefighting.

Answer 10

1-2 liters

Question 11

Sweat loss of _____ per hour has been reported during work in a hot environment while wearing PPE.

Answer 11

2.8 pounds

Question 12

Heat Illnesses (Check p. 142)

Answer 12

1. Heat Rash
2. Heat Cramps
3. Heat Exhaustion
4. Heatstroke
5. Rhabdomyolysis

Question 13

Heat Exhaustion should be treated aggressively by:

Answer 13

1. Removing gear
2. Moved to cool shaded area, upwind
3. Active and aggressive cooling (misting fans, forearm immersion, or full body submersion
4. Rehydration

Question 14

What is the most severe form of heat illness?

Answer 14

Heatstroke

Question 15

Heatstroke occurs when there is a depletion of salt and water and an impaired ability to effectively thermoregulate.

Question 16

What is often the first sign of heatstroke?

Answer 16

Central Nervous System Dysfunction
- Confusion
- Irritability
- Seizure
- Cardiovascular Collapse

Question 17

Rhabdomyolysis

Answer 17

Breakdown of muscle as a result of damage to the tissue.
- Breakdown or death of muscle allows electrolytes and proteins (esp. creatine kinase and myoglobin) to leak into the blood stream.
- Altered blood stream is dangerous for heart, brain, and kidneys.

Question 18

Risk factors for heat illness

Answer 18

1. Poor physical condition
2. Excess Body weight
3. Dehydration and salt depletion
4. Chronic disease
5. Minor illness
6. Skin problems
7. Medications
8. Prior heat exposure
9. Prior heat injury
10. Recent alcohol use
11. Genetics
12. Lack of heat acclimatization

Question 19

HR was approx. ________ higher when wearing PPE compared with weighted vest (doing same exercise and carrying same weight)

Answer 19

47 bpm

Question 20

Steps to combat negative consequences of heat stress

Answer 20

1. Proper hydration
2. Physical fitness
3. Engaging in incident scene rehabilitation

Question 21

What is one of the most powerful protectors of health and a vital preventative strategy for reducing negative heat-related consequences?

Answer 21

Physical fitness

Question 22

Primary goal of rehab?

Answer 22

Ensure physical and mental condition of members operating at the scene do not deteriorate to a point that affects the safety of others or jeopardizes the integrity of the operation.

Question 23

What is the goal of cooling?

Answer 23

Decrease core body temp, not just to make the FF feel cooler.