## 4 Discussion  
For the present case report, we aimed to analyze the psychophysiological response of one participant recreating the evolutionary physical activity and nutritional context of hunter-gatherers. The decision to have one participant undergo fasting while the other did not was intentional and designed to simulate the inherent variability and unpredictability of the hunter-gatherer lifestyle. It was common for hunter-gatherers to face days of least and famine depending on the success of their hunting or gathering activities. By having one participant fast while the other did not, we aimed to explore a broader spectrum of the evolutionary lifestyle, from periods of relative abundance to those of scarcity. This approach was chosen to provide a more holistic understanding of how such disparate conditions within the same overarching lifestyle could differentially impact psychophysiological responses. Regarding the analysis of autonomic modulation through HRV, no differences were found between the participant in a fasting state and the control participant. Literature shows that ultramarathons are events that elicit significant anticipatory anxiety caused by the fight-or-flight system, and this elevation in sympathetic modulation persists until the end of the event [12]. Additionally, it has been verified that parasympathetic baseline values recover 2 days after the event [15]. Therefore, the evaluated test was consistent with the measurements found in previous ultraendurance events. The results obtained by the fasting participant are in line with the HRV findings reported in the literature. Thus, fasting did not affect HRV values in this type of test. Regarding cortical activation, it was found to slightly decrease after each stage in both participants. This phenomenon could be related to a decline in information processing capacity due to central nervous system fatigue [16], as the stressful nature of these events on athletes has been documented [12]. Therefore, this response could be attributed to sympathetic nervous system hyperactivation [17]. However, in our study, reaction time values showed a decrease in both participants. This could be another example of how ultraendurance tests induce central fatigue without causing mental fatigue [18]. In fact, the consequences of exercise-induced mental fatigue may be specific to the measurement task, the timing of the test, the duration of physical exercise [19], or its intensity [20]. Hence, further research is needed on exercise-induced mental fatigue in ultraendurance. In the present study, RPE levels were elevated in both participants after completing the event, with the fasting participant showing the highest levels. This finding is consistent with previous studies in ultraendurance, where despite the low intensity of the event, an extremely negative energy balance and maximal RPE values [21] were observed at the end of the test. Furthermore, RPE has been shown to increase under fasting conditions in measurements of isokinetic muscle function [22]. Therefore, it is possible that lower or insufficient nutritional intake during ultraendurance tests is associated with higher RPE. However, in our study, we cannot confirm this, as the higher RPE in the fasting participant coincided with lower preparation for ultraendurance events. Regarding the perception of stress, the fasting participant exhibited moderate values, while the control participant maintained low and constant levels throughout the four