spancolor: #0000ff""Problems of heat balance in hot weather
Human being maintain body temperature with in a very narrow range under varying environmental temperature. That is why like birds & other mammals, man is also called homoiotherm. The human body , like the internal combustion engine produces heat in the process of converting food into energy. 80 to 85 % of the energy liberated as a result of metabolism is in the form of heat. Body gets rid of excess heat produced to prevent over heating.
Human body must maintain heat balance not only under normal , comfortable conditions but also under adverse conditions of hot weather.
Heat exchange between body and environment or to be more exact heat loss during hot weather takes place by four types of physical processes.
spancolor: #0000ff""CONDUCTION:
When there is surface to surface contact , heat is transferred from hotter objects to the other one.
spancolor: #0000ff""CONVECTION:
Heat is lost from the body to low temperature moving wind . Loss is increased by movement of the body or increase in speed of wind.
spancolor: #0000ff""RADIATION:
The human body receives heat by radiation from the hotter objects e.g. sun . Body loses heat by radiation to environment when later is cooler.
spancolor: #0000ff""EVAPORATION:
This is most important during hot weather . Evaporation of water from the body surface and respiratory mucosa results in heat loss and cooling of the body . It is interesting to note that the process requires 580 cal (2.3 BTU) of heat to change 1gm of water to its vapor state at body temperature.
Sweating begins at a skin temperature of 33 C and increases in proportion to heat load. Relative humidity plays important role in the process of heat loss through evaporation. Less humidity more evaporation.
Generally speaking all hot climates are tolerable for the suitably acclimatized person , except for occasional very temporary occurrences of intolerable extremes of these conditions.
spancolor: #0000ff""Physiological effects of heat load are :
Increased blood flow to the skin.
Cardiac output increased , may be doubled or tripled.
Up to 4 quarts of fluid loss in sweat depending upon temperatures and duration of exposure.
spancolor: #0000ff""Heat stress results in :
Adverse effects on vital body functions.
Impairment of mental efficiency.
spancolor: #0000ff""Increased body temperature results in :
( Impaired mental efficiency) :
Decreased work done
Increased errors
Adverse effects on vital body functions : Excessive heat load may result in failure of temperature regulating system and overheating. Depending on type and duration of exposure and on the state of acclimatization of the individual these heat disorders may result:
spancolor: #0000ff""Muscle cramps :
Decreased muscle coordination
Pain
spancolor: #0000ff""Heat Collapse:
Lowering of blood pressure
Fainting
spancolor: #0000ff""Heat Stroke:
Delirium, seizures, coma
Brain damage
Death
spancolor: #0000ff""INDUSTRIAL OPERATIONS:
To understand specific heat balance problems in industrial operations it is important to look into the sources of heat.
Climate or weather
Industrial factors
Kinetic heating
Radiant heating
Operator / Technician (human being factor)
Metabolic heat production
Protective equipment which reduces heat loss
This means that in industrial operations heat load is much more than actual weather effect.
spancolor: #0000ff""PRECAUTIONS :
spancolor: #0000ff""ACCLIMATIZATION :
Major changes occur within a week and are chiefly cardiovascular. Circulation adapts itself to the greatly increased cutaneous (skin) blood flow to dissipate more heat.
spancolor: #0000ff""HOW TO ACCLIMATIZE :
Have short periods of moderate exercise
Avoid spending too much time in air-conditioned areas
Avoid excessive exertion
spancolor: #0000ff""ADVANTAGES OF ACCLIMATIZATION :
Greater efficiency
Improved evaporative cooling
Personal comfort
spancolor: #0000ff""OTHER PRECAUTIONS :
Avoid working in direct sun
Protect skin from sun burn
Wear light colored and light weight clothing
Use little additional salt ( Lassi , fresh lime , etc. ) . Excessive salt intake by salt tablets etc . is not necessary and in fact may be harmful.
Avoid dehydration , no rationing of water.
spancolor: #0000ff""FIRST AID :
Heat Collapse or heat exhaustion : ( There is normal body temperature , pale & clammy skin, sweating , weakness , nausea. ). Move victim to a cool , shaded place . Lay him down and give sips of cold water if conscious. If unconscious check / maintain ABC {airway, breathing , circulation ( heart beat)}.
Get medical help.
spancolor: #0000ff""Heat Stroke :
(There is very high body temperature , hot & red skin , rapid & strong pulse). Move victim to a cool , shaded place. Remove clothing. Cool him by wrapping in a cold & wet sheet. Keep sheet cool & wet by pouring cold water on it. Don't over chill him. Place in recovery position if unconscious and check & maintain ABC . Get medical help.
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