Heat-health warning systems: integrating physiological knowledge and climate information into operational advices for occupational purposes

All European countries have climate services providing forecasts on upcoming weather scenarios and cross-national collaboration improves the ability to predict forthcoming heat events with high spatial resolution. Many European countries have developed their own heat-health warning systems referring to the general population or specifically targeting heat-vulnerable citizens such as elderly. However, systematic translation of effective information to the individual level is lacking and we should consider the personalized physiological characteristics e.g. endogenous heat production and individual heat dissipation capacity. Heat stress in workers is of special interest and importance because they are frequently engaged in intense physical activities combined with exposure to sunlight or industrial heat and sometimes required to wear specific clothing that limits perspiration. To target this issue, the “Heat-Shield” project will develop a heat warning system to anticipate threats to worker’s health and disseminate adaptation measures. An effective occupational heat warning system should consider the complex set of meteorological conditions that affect heat-discomfort in shaded and sunny outdoor conditions and their relationships with health events and the physiology of workers engaged in various occupational activities. The Wet Bulb Globe Temperature (WBGT) represents a thermal indicator originally developed for military activities and subsequently widely applied for occupational purposes with modified WBGT thresholds. In particular, WBGT thresholds have been adapted depending on physiological and behavioural occupational conditions, such as the workload, clothing and acclimatization status of the workers will be considered in the evaluation. Based on these conditions, specific preventive measures, such as work/rest schedule timing and hydration recommendations will be provided. In addition, it is increasingly necessary to acquire more and more detailed physiological information obtained by monitoring conducted directly in the workplace in order to implement the Heat-Shield heat warning system to improve the further translation/down-scaling to the individual occupational level.