## 3 Discussion
The non-enzymatic antioxidant includes glutathione, uric acid, and bilirubin [26]. However, under certain pathological conditions or in the presence of IDA, the endogenous antioxidant defense system can become overwhelmed. This disruption leads to an imbalance between the production of ROS and antioxidant defense system, resulting in the accumulation of ROS and increased oxidative stress [20]. The depletion of endogenous cellular antioxidant systems has been associated to the damage caused by oxidized cellular components [29]. Antioxidants act as scavengers of excess ROS in human system and play a major role in detoxifying excess ROS [30]. Furthermore, antioxidants assist and maintain the body's delicate oxidant/ antioxidant balance or hemostosis [30]. Given the significance balances of antioxidant system, there is a considerable interest in developing different strategies to enhance endogenous antioxidant capacity. One promising approach involves targeting H2S producing enzymes, CSE, CBS, 3 MST, which can increase H2S endogenous levels, and thus enhance antioxidant activity. The emission of thermal spring components can have varying impacts on the environment and human health, which are influenced by the levels and duration of exposure. These impacts can be both positive and negative. It is important to consider the specific composition of thermal spring emissions and the concentration of different components, including H2S, as they can determine the potential effects on the surrounding ecosystem and individuals exposed to them. In our study, we focused on investigating the visitation patterns to thermal springs, and specifically examining the frequency and duration of visits among the study participants. These visitation patterns were assessed to understand the frequency and duration of exposure to the thermal springs among the study participants and gather valuable insight into their level of engagement with the H2S thermal spring environment. Through our analysis, we observed that visitation is related to the enhancement of the endogenous activity of H2S-releasing enzymes, as well as a substantial increase in the antioxidant capacity among IDA patients. These findings highlight the potential benefits of regular visits to thermal springs, where a visit duration of 2-3 h was found to be particularly beneficial for individuals with IDA, as it can contribute to the improvement of their overall health and well-being. Based on our results, we highly recommend considering regular visits to thermal springs as a means of obtaining these beneficial effects. However, it is important to note that further research and clinical studies are necessary to validate these findings and provide more comprehensive evidence regarding the therapeutic potential of thermal spring visitation in the management of IDA and associated conditions. For a deeper understanding of the specific mechanisms and underlying physiological changes associated with thermal spring visitation and its impact on endogenous activity, we encourage referencing scientific studies and research articles in the fields of hydrotherapy, balneology, biochemistry, and related disciplines. Typically, the biological effects of H2S exhibit a biphasic response, with low-to-mid levels typically evoking regulatory, protective, or stimulatory effects [31]. Conversely, high toxic levels of H2S tend to produce the opposite effect, which is frequently related to the inhibition of mitochondrial Complex IV [31]. Inhalation of high levels of H2S can cause acute respiratory symptoms, including irritation of the respiratory tract, coughing, shortness of breath, and in severe cases, pulmonary edema [32]. Additionally, H2S can exert systemic effects on the central nervous system, manifesting as symptoms like headache, dizziness, confusion, and even loss of consciousness [32]. Prolonged or repeated exposure to H2S may contribute to chronic effects, including neurological symptoms, memory impartment, and respiratory issues.