Screening for Heat Stress in Workers and Athletes

Abstract

Heat-related illnesses lead to almost 6000 hospital visits per year, or two emergency department visits per 100,000 visits. Heat-related illnesses are most high among men (72%) aged 15 to 19 years and are most often associated with athletic activities (1). Global climate change will continue to have an impact on heat stress in people, on animal survival, and on food availability. The World Health Organization has estimated that over the past 30 years, 150,000 lives have been lost annually due to global heat waves and climate change (2). Weather changes have a great impact on athletes and workers by slowing efficiency and decreasing productivity (3, 4). When heat waves occur, overall mortality is also affected among the old and the young, due to their increased risk of dying from cardiovascular, respiratory, cerebrovascular, and some cardiovascular diseases, such as ischemic heart disease, heart failure, and myocardial infarction (3). Despite increasing temperatures and environmental levels of carbon dioxide, one third of metropolitan areas do not have heat stress response plans (5). Cases of heat stress are handled on a case-by-case basis rather than by being addressed collectively as a public health concern. The National Institute for Occupational Safety and Health initiated heat stress criteria in 1986 and amended them in 2008 regarding worker heat stress safety (6). Few people are aware of these criteria, of the risk factors associated with a predisposition to heat stress, or of the signs or symptoms to look for that represent risk factors for heat stress. The rules and standards proposed by the Occupational Safety and Health Administration for workplace heat stress are recommendations and still not enforceable (7). Screening for heat stress susceptibility in workers and athletes is an issue in need of public health criteria with enforceable rules based on evidence-based research. Screening for heat stress risk factors should consider physical demand level; cardiovascular, pulmonary, and endocrine status; previous history of heat stress; age; diseases; and medications including illegal drug use. Such screening should be part of the recruitment of any person expected to work or play in extremely hot environmental conditions. Older people are at increased risk for cardiovascular and thermoregulatory instability. The aging American workforce, undiagnosed disease, poor hydration while working or playing, and global warming are all factors that contribute to the need to screen workers and athletes for the risk of heat stress (8). This article first reviews some physiological aspects of temperature regulation and then provides a formula for heat stress testing, discusses guidelines for screening, and reviews accommodations for those susceptible to heat stress.