This study revealed inadequate knowledge and adaptation behavior among the studied population, with relatively high knowledge gaps. Age and education were the most significant predictors of knowledge and adaptation behavior.

The term climate change was understood by less than half of the study’s participants; these results were similar to the study in the Offinso municipality, Ghana, where only 31.9%of respondents had heard about it [13]. Media and the internet were the primary and most common sources of heat-related information for solid waste disposal workers, as observed in similar studies from China, Ghana, and South Australia [9, 13, 16].

On the other hand, a survey study among health and safety representatives in Italy revealed adequate high knowledge about climate change when healthcare providers were identified as the primary information source by respondents (34.4%), followed by professional courses (28.2%), and conventional media (14.3%) [15]. Media and mobile apps can be used as an opportunity for information and online training. A USA study found that smartphone/tablet applications and online training were occupational workers’ preferred heat stress training methods [17].

It should be stressed that while conventional media and new media frequently emphasize the emotional aspects of climate change, they occasionally raise the concerns of their audience; more scientifically accurate information sources such as professional courses and healthcare professionals usually address such a phenomenon through a rigid purely rational explanation that may be mistakenly perceived as condescending [18]. To avoid this, the Occupational Safety and Health Administration (OSHA) and the National Institute of Occupational Safety and Health (NIOSH) in the USA jointly developed a mobile app that can be a helpful tool for determining how hot it feels during the day and using that information to plan outside job activities. It has a real-time heat index and hourly forecasts specific to worker location. It also provides occupational safety and health recommendations [19].

The interest in the impact of heat-related events on workers’ health and safety has recently increased. Evidence suggests that scorching weather contributes to excess morbidity and mortality, particularly among older aged individuals and patients undergoing pharmacologic treatment for non-communicable diseases [20]

Half of the participants in this study got sick between June and November while working in the heat. This illness rate is lower than the rate reported by two studies of outdoor workers in Zimbabwe [14] and the USA [21] where 57 and 64% of the respondents respectively reported experiencing a symptom consistent with HRI during a hot day. Headache was reported as the most common symptom suffered by participants, followed by muscle aches, elevated body temperature, difficulty breathing, dizziness, insomnia, and hot, dry skin [14]. Kearney et al.’s study in the USA also reported that the prevalence of having one HRI symptom was 72% and 27% among workers having three or more HRI symptoms [21]. Heat illness was higher than the rates reported by multiple other studies; in Uejio et al.’s study, in the USA, about 20% of workers reported experiencing one or more heat-related symptoms during the previous summer [1]. About a third of outdoor workers reported heat illness while working outside in another US study [22]. A study by Han et al. in China reported that only 11.6% of the participants had experienced heat-related illnesses in hot weather [9]. In another study in Italy, the percentage of HRI cases who required first aid or medical intervention was 10.49% [15].

The differences in the rates of heat-related illness in these studies demonstrated that intense and prolonged occupational exposure to elevated temperatures and working under direct sunlight is directly associated with the frequency of adverse health effects, such as dehydration and spasms, increased fatigue, and reduced productivity. This draws attention to the defective measures in intervention and defects in preventive measures specifically designed for severe hot climates during the warm season. Emphasizing administrative controls, particularly educating field supervisors and workers on how to avoid and recognize HRI, should be a priority.

More than half of the solid waste disposal workers reported that wearing thicker clothes does not help in maintaining a low body temperature. Similar to these results, Arcury et al. [21] and Kearney et al. [22] reported that outdoor workers wearing hats or dry clothing were less likely to experience HRI symptoms. Clothing can inhibit or prevent sweat evaporation and convective cooling [23]. Generally, heat exchange is hampered significantly by clothing that is heavier or less permeable [24]. Some types of clothing can prevent this mechanism from working, even in cool ambient conditions, by blocking the flow of cool, dry air over exposed skin [25]. Impermeable coveralls, for example, can prevent sweat from evaporating, and clothes and personal protection equipment (PPE) can generate microenvironments that retain heat close to the skin. Adjustments to exposure limits and work-rest regimens are necessary, based on the type of clothes and the job’s physical demands. Employers must be aware of this and take the necessary actions to remedy adverse workplace condition s[26].

Our results showed a deficiency in workers’ knowledge regarding the effects of climate change on the environment and types of heat-related illnesses. Only about one-third had adequate knowledge about these topics. Evidence shows that outdoor workers’ awareness of occupational heat stress varied by country/region and industry [27]. Usually, workers in developing nations typically have lower knowledge of heat risk and awareness of climate change than workers in developed nations [28], with a few exceptions, such as in Ghana [27] and in a USA study, in which outdoor worker awareness was only (8%) [29].

Compared with a study from Australia, Australian outdoor workers were almost twice as concerned about heat exposure as the present study’s participants [16] Our study’s relatively low awareness of workplace heat exposure may reflect the cultural and demographic differences between the two countries.

On the other hand, about two-thirds of the studied workers had adequate knowledge about symptoms of heat exhaustion, the symptoms of heat stroke, and that fainting and collapse could be due to heat-related illnesses. Published studies have consistently found that most workers in developing and developed countries have a good knowledge of heat illnesses [30, 31].

Evidence from the USA [29], India [32], South Africa [33], and Australia [34] showed that outdoor workers had a good knowledge of the symptoms and severe outcomes of excessive heat exposure. While physicians sometimes find difficulty in recognizing the early stages of [35, 36], workers often exhibit a good knowledge of symptoms and possible outcomes of excessive heat exposure, particularly in high-risk settings [16, 37].

Unsurprisingly, redesigning workplaces to avoid or minimize heat exposure among workers may sometimes be problematic or vastly exceed the available resources. However, many available heat management protocols, standards, and guidelines exist. Following these guidelines helps to lower or even avoid heat-related illnesses.

Our results showed that most participants had a deficiency in preventive measures (e.g., keeping hydrated, wearing light-colored breathable clothes, and stopping work). Keeping hydrated is vital to prevent heat stroke; however, cool drinking water may be unavailable during all working times. The unavailability of safe and cool drinking water in the workplace has been reported in different studies from Australia and the USA [16, 17].

The most prevalent work-related heat adaptation in our study was drinking plenty of fluids. This lower percentage of drinking water as a method of protection from heat-related illness is similar to the study from Moda et al. in which increased hydration was identified as a less common (43–58%) strategy used by the general public [38]. The percentage of drinking water as a method of protection was less than the rates reported in other studies where outdoor workers protect themselves from the heat by drinking plenty of liquids (85% and 90%), followed by wearing a hat and seeking shade (46% and 40%) [1, 15].

US federal guidelines recommend that outdoor workers drink ~ 0.25 L of cold (< 15 °C) water every 15 to 20 min [26]. When workers engage in moderate physical activity in the heat, sports drinks with balanced electrolytes should be consumed if sweating continues for several hours, and alcohol and beverages with a lot of sugar or caffeine should be avoided. Generally, six cups of liquids each hour is the maximum recommended consumption [19].

According to the OSHA guidelines, workers should rest for 15 min after each hour of work when White bulb globe temperature (WBGT) exceeds 26 °C, 30 min after each hour of work when WBGT reaches 28 °C, and 45 min of rest after each hour of work when WBGT reaches 30 °C [39].

Heat prevention strategies mainly include regulations, administrative controls, and engineering modifications. Currently, there are systematic technical guidelines and manuals in place for heat stress monitoring, risk assessment, control, and prevention, such as the ISO (International Organization for Standardization) heat indices, ACGIH (American Conference of Governmental Industrial Hygienists) guidelines, and NIOSH (US National Institute for Occupational Safety and Health) guidelines. The core elements of all heat-related illness prevention programs such as CDC, NIOSH, and OSHA are as follows: consuming adequate fluids, working shorter shifts, taking frequent breaks, quickly identifying any heat illness symptoms, engineering controls such as air conditioning, cooled air, and increasing airflow, changing workloads and schedules, and providing training to all supervisors and workers about heat-related symptoms and first aid [39, 40].

Evidence has shown that outdoor workers’ knowledge and awareness of HRI are affected by factors such as level of education, age, culture, country, duration of employment, and the local occupational safety management system [30] Usually, outdoor workers in developing countries had lower climate change awareness and adaptation behavior levels than workers in developed countries [31]. Our study’s analysis of the relationship between age and the total scores for knowledge and adaptation behavior showed that older workers were less aware of heat exposure than younger workers. Occupational HRI has been reported to occur more in younger workers, particularly workers who generate metabolic heat from heavy physical labor in hot environments [1]. The increased risk for younger workers (under 25 years old) could be caused by the more arduous tasks and physical activity experienced by workers in this age group. Also, younger workers are more likely to undertake physically demanding tasks in the workplace. Moreover, they often need more safety training or have fewer skills than older workers [38]. Some studies also observed that younger workers might be less likely to recognize the risk of heat exposure and show low compliance with preventive measures [39]. Older workers tend to choose duties with less exposure to direct sunlight and extreme heat. They have more power and authority than younger workers in choosing tasks in the workplace [40]. This highlights the need to prioritize improving the HRI and safety awareness of older solid waste disposal workers.

Interestingly, our results showed that knowledge and adaptation behavior of workers were significantly associated with educational level, which is inconsistent with an Italian study by Ricco et al, which revealed that higher educational achievements were positive predictors for higher workers’ awareness ,[41] underlining the substantial impact of appropriate information and education of workers in the process of building up appropriate awareness towards health risks.

This study has some limitations that should be mentioned. Firstly, to the author’s knowledge, this is the first study to discuss climate change and HRI among solid waste disposal workers in Egypt, so there is a deficiency in studies to compare the situation in different regions in Egypt. Secondly, bias in recall and self-reporting inevitably exists in a cross-sectional observational study. However, we have taken measures such as piloting the questionnaire and shortening the recall period to minimize its impact.