[ARCHIVED] How efficacious and how practical are personal health protection measures recommended to reduce morbidity and mortality during heat episodes?
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The potential impact of elevated temperatures on mortality and morbidity is severe. Every year, hospitalizations and deaths occur in numbers well above average during and just after days of extreme heat, particularly in vulnerable populations. Persons living in urban environments may be particularly at increased risk for mortality from ambient heat exposure (urban heat island effect). Other risk factors that have been identified are: being under four years of age or older than 65; being in poor general health; taking medications that aggravate dehydration and heat exhaustion; being overweight; being socially isolated; overexerting during work or exercise; and, being confined to bed. With a world of warmer summers, climatic instability, and an aging population increasingly more isolated and more medicated, efficient measures to reduce the risk of heat-related death are crucial.
This review was conducted to establish what health protective advice is offered by public health and civil protection authorities in general, and specifically during heat episodes. The incoherencies and discrepancies of health messages given by various sources were evaluated and a critical assessment of the efficacy of this advice was conducted by reviewing current evidence supporting these measures on the basis of observational studies and from the physiology of the human response to heat.
By reviewing the relevant epidemiological, physiological, and experimental studies in each area, it became evident where more research needed to be done. Practical advice was identified, notably: increasing hydration; monitoring those taking medications that disrupt heat responses; acclimatizing slowly to the heat; reducing activity level; and, using electric fans to enhance evaporative cooling or to supplement other cooling techniques. Some of the advice, not well supported by scientific evidence, was avoidance of fan use, and avoidance of caffeinated and sweetened drinks, and all alcoholic beverages. Areas where knowledge gaps exist included: use of devices other than air conditioning to enhance cooling and ventilation; hydration and activity needs and limitations of heat-vulnerable populations; and the level of risk during heat waves, presented by commonly-taken medications.