Effect of thermal injury on liver and role of heat preconditioning

Elevation of ambient temperature (Ta) in last two decades is subject to high risk of thermal insult to all inhabitants. Heat stress (HS) is marked by hyperthermia: a condition in which core body temperature (Tc) > 37°C (1). Normal temperature range of 24-26°C is an ideal to health concerned with maximum productivity of an individual. Temperature range from 33-34°C is associated with reduced labour roductivity and loss of 50% work capacity (2). The global average temperature is estimated to increase by 1.8-4°C by the end of this century Based on this, it has been estimated that there will be loss of 2.2% working hours by 2030, which can also go upto 3.8% if agricultural and construction work will be continued under open sunlight (3). In the coming decades HS will be one of the most critical factor of climate change and severing threat to human health worldwide. According to Indian metrological department, year 2020 was the eighth warmest year in the last century. On accounting larger areas on the globe it was found that 2019 was second warmest year on the

record. Massive impression of extreme heat waves resulted 700 deaths and 3,300 fatal cases of heat stroke during 1995 in Chicago (4,5). In India, during 2001-2005 mortality count was about 3,863 which further raised upto 6,429 between the years 2011-2015 (6). Worldwide,

burst of heat is responsible for many mortalities including 14,800 deaths in France alone and total 70,000 deaths were recorded across the Europe in the year 2003 (7,8). In Russia alone 55,000 mortality also occurred in the year 2010 (9,10). According to world metrological

organization approximately 220 million peoples were exposed by vulnerable heatwave in the year 2018 (11). Heat related mortalities and uncounted severe conditions has been reported in era of 1971-2020 and future estimation also suggest that it will increase rapidly globally (12). Exposure to high Ta is a natural hazard and life threatening which is constantly expanding on human health with large number of mortality across the globe. Individuals affected by HS such as soldier's, fire-fighter's, labourer's, pregnant women's, mine workers, athlete's and old age persons are especially at high risk. Studies has shown that 30% of heat stroke survivors experienced disability and neurological dysfunctions even after cooling of the whole body (4,7). It has been observed that upon prolonged exposure to heat, stored

ingredients are drained from the body and heat build-up begins to cause dizziness, muscle cramps and fever. Available literature indicates that high Ta adversely affects a wide variety of cellular and molecular functions. HS is multi-modular in nature and have different