HEAT WAVE = Three or more days during which the air temperature is >
32.2C
Normal Response to Heat:
Narrow range of body temperature for "health".
Balance between heat generated through metabolism and the
external environment...
Heat Gain = M +/-C+/-K+/-R+/-E
M = metabolism
C = conduction
K = conduction
R = radiation
E = evaporation
Mechanisms of Heat Loss:
-
Radiation:65% of heat loss
-
Conduction: < 2% [increases with water immersion]
-
Convection: 10% of heat loss
-
Respiration: 5%
-
Evaporation: 30% @ rest and up to 75% with activity.
Is the most effective means for dissipating heat, however, above
95% humidity, evaporation no longer occurs.
Predisposing Factors:
Prolonged Exertion:
·
athletes
·
military
·
outdoor work
Poor muscle conditioning
Lack of Acclimation
Sleep deprivation
Poor living environment
Disease:
·
CVD
·
Dehydration
·
Endocrine disorders: diabetes, thyrotoxicosis,
·
Neuropathies
·
Hypothalamic disease
·
Skin Disorders: burns, scleroderma, CF
·
Infections: malaria,
·
Seizures
Extremes of AGE: very young and old
Medications and Drugs:
·
anticholinergic agents: TCA's, Phenothiazines
·
Amphetamines and cocaine
·
Alcohol
In the 1995 Midwest Heat Wave, the most common
comorbid conditions were: nervous disorders,
endocrine disorders, respiratory ailments, and
mental disorders.
