Background: Heat-related illnesses (HRI) are defined as elevated body core temperatures when exposed to an intense high temperature. HRIs include but are not limited to heat exhaustion (HE) and heat stroke (HS). HE and HS are among the leading causes of morbidity and mortality among pilgrims when the Hajj season occurs during the hot cycle of the year in Makkah. Methods: A retrospective cross-sectional data analysis was conducted on HRI cases during Hajj 2022/1443 Hijri. The data were extracted from the Hajj electronic health records system software immediately at the end of the Hajj period. Results: A total of 200 patients presented with HRI symptoms during the study period. Over half of the HRI patients were male (n=116, 58%). The mean age was 44 ± 14.6 years. One hundred forty-three patients (71.5%) were diagnosed with HE, while 57 (28.5%) were diagnosed with HS. A statistically significant association between age and HRIs was observed. Conclusion: More HRIs are expected due to the gradual elevation of ambient temperature and the global warming phenomenon. This study emphasizes the importance of education and awareness regarding preventive measures in the general population, especially among the most vulnerable subpopulations.

Keywords: Heat related illnesses, Hajj, Mass Gatherings, Public Health.