Thermal Stress at workplace

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Thermal Stress at workplace

• Ass. Prof. Dr. Laith A. Alrudainy

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Thermal Stress

• Thermal stress is defined as the physical and
  physiological reactions of the human body to
  temperatures that fall outside of the human
  normal comfort zone.

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Temperature Regulation

• The hypothalamus is a small organelle within
  the brain which adjusts bodily functions through
  hormones which
• -Increase heart rate
• -Begin the sweating mechanism
• -Increase blood flow to the skin surface

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How does the body rid itself of excess heat?

• There are 4 means of heat removal from the body.
• Convection
• Radiation
• Evaporation
• Conduction

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What are the health effects of heat
stress/strain? Heat RashSunburnHeat Fatigue
Heat CrampsHeat Exhaustion Heat Stroke
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Heat Exhaustion

• Cause Depressed condition of the circulatory
  system due to a lack of adequate fluid
  replacement (dehydration). Blood vessels dilate
  and blood flow is seriously reduced (clinical
  condition of shock has occurred).
• Symptoms Nausea, dizziness, weakness, headache,
  blurred vision, profuse sweating, cold/wet
  (clammy) grayish skin, unconsciousness, coma and
  death.

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Heat Exhaustion (continued)

• First Aid Place victim in a face down position
  in a cool location, administer fluids if the
  victim is conscious. If unconscious, seek
  medical care or transport to a medical emergency
  room.
• Seriousness Shock is a serious medical
  condition regardless of the cause of its onset.
  Victims may require several days or even weeks to
  recover.

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Heat Stroke

• Cause The bodys temperature regulation
  mechanism, located in the hypothalamus, fails and
  sweating stops. Core body temperature rises
  dramatically and the victims condition becomes a
  serious medical emergency.
• Symptoms Chills, restlessness, irritability,
  euphoria, red face and skin, disorientation,
  hot/dry skin (not always), collapse,
  unconsciousness, convulsions and death.

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Heat Stroke (continued)

• First Aid Immediate, aggressive cooling of the
  victims body using wet cloths, immersion into
  cool water or using alcohol wipes. Transport to
  emergency medical facility.
• Seriousness Heat Stroke is a MEDICAL EMERGENCY.
  Without outside intervention, the victim will
  die.. Recovery times from heat stroke are
  generally the longest of any heat-related
  disorder.

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Heat effects and people

• Heat affects people in different ways.
  People come in all different sizes, shapes, and
  tolerances for heat.
• Some people can work comfortably in high
  temperatures, while others will develop sickness
  from heat stress/strain

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Heat effects

• Predisposing Factors
• very small body size
• poor nutrition
• overweight
• over 40 years old (the older the more sensitive)
• previous heat illness
• heart disease
• high blood pressure
• diabetes
• skin disease
• liver, kidney, and lung problems

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Heat effects

• Predisposing Factors, contd
• poor physical condition
• fatigue
• excessive clothing
• dehydration
• being female
• being pregnant
• alcohol, caffeine, nicotine intake
• Sunbathing

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Heat effects, contd - Drugs

• Drugs that interfere with bodys
  thermo-regulation
• Heat production
• thyroid hormone
• amphetamines
• Decrease sweating
• antihistamines
• anticholinergics
• phenothiazines
• Benztropine

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Cold Stress
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Hypothermia

• a decrease in the core body temperature to a
  level at which normal muscular and neurological
  functions are impaired
• Hypothermia is possible at any temperature under
  98.6 F degrees.

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Hypothermia - signs

• Shows decreased physical and mental capacity.

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Hypothermia - mild

• Mild Hypothermia
• - core temperature 98.6 96 F
• - non-voluntary shivering
• -complex motor functions impossible
• -vasoconstriction to periphery

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Hypothermia - moderate

• Moderate Hypothermia
• - core temperature 95 93 F
• - loss of fine motor coordination
• - slurred speech
• - violent shivering
• - apathetic attitude

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Hypothermia - severe

• Severe Hypothermia
• - core temperature 92 86 F or below
• - shivering in waves
• - person curled in fetal position to conserve
  heat
• - muscle rigidity develops
• - pale skin/dilated pupils
• - reduced pulse
• Severe Hypothermia is LIFE THREATENING!

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Cold Injuries

• Although hypothermia is well known, there are
  other cold injuries.
• -Frostbite
• -Immersion foot (trench foot)

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Frostbite

• Frostbite is a freezing of the surface and deep
  layers of tissue.
• Characterized by
• - white, and feels woody
• - numbness, possible anesthesia
• - deep frostbite can affect bone and muscle
• - purple/black color is from ruptured blood
  vessels

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Frostbite - treatment

• Immerse affected area in 105 110 degree F water
  until thawing is complete.
• - part will be extremely painful
• Wrap affected part in sterile gauze
• Affected part should not be used for anything
• - keep part from refreezing

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Immersion Foot trench foot

• Immersion foot is caused by prolonged exposure of
  the feet to wet, cool conditions.
• Characterized by
• - yellowish, smelly feet
• - possibly numb
• - sloughing of skin tissue/itching
• Immersion foot may cause permanent damage to
  foot tissues, leaving person susceptible to cold
  injuries in future.

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Immersion Foot - treatment

• Careful cleaning and drying of feet.
• Keep feet dry as much as possible.
• Keep off feet as much as possible until healed.

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Thank you