## 4 Discussion
Through this form of regulation, PBMT contributes to improved metabolic stability and energy efficiency [64; 65]. Its anti-inflammatory effects further enhance cellular energy metabolism by reducing neuroinflammatory mediators and mitigating oxidative damage, which are closely linked to fatigue in chronic conditions [66; 70]. Moreover, PBMT promotes mitochondrial biogenesis, leading to an increase in both the number and functional capacity of mitochondria within cells [63; 72]. In parallel, it enhances microcirculation via nitric oxide synthase-dependent pathways, promoting vasodilation and improved local blood flow [69; 71]. Notably, PBMT modulates capillary-level microvascular responses, where interindividual variability may partially account for differences in clinical outcomes [73; 74]. PBMT has also demonstrated significant improvements in the patient's QoL, particularly when applied as a whole-body treatment. Studies have reported sustained enhancements in FIQR and SF-36 scores [36], likely due to PBMT's effects on autonomic regulation, mitochondrial function, and systemic inflammation modulation [35; 75]. Whole-body PBMT positively influences the autonomic nervous system (ANS) by restoring the sympathetic-parasympathetic balance, reducing heart rate variability disruptions, and improving vagal tone factors frequently altered in Fibromyalgia [63, 70, 76]. Additionally, its ability to enhance mitochondrial bioenergetics and ATP synthesis contributes to increased cellular resilience and energy availability, helping to alleviate fatigue and systemic dysfunction [77, 78]. In contrast, localized PBMT exhibits only moderate benefits, with some studies reporting no significant differences compared to conventional treatments, such as local anesthetic injections [47]. This limited impact on the patient's QoL may be attributed to its primary focus on localized pain relief without addressing the broader systemic dysfunctions often present in Fibromyalgia, including ANS dysregulation and neuroinflammation [43, 65]. Conversely, whole-body PBMT appears to exert neuromodulatory effects by modulating neurotransmitter release and reducing neurogenic inflammation, which may contribute to improvements in sleep quality [79, 80] and cognitive performance [44, 61, 81, 82]. Additionally, patients frequently report increased motivation and a subjective restoration of their baseline well-being, potentially linked to PBMT's capacity to modulate neurotrophic factors and enhance synaptic plasticity [68, 77, 83, 84]. Beyond its physiological and analgesic benefits, PBMT has demonstrated positive psychological effects, including reductions in kinesiophobia and improvements in self-efficacy [38, 40]. These findings align with previous research suggesting that PBMT enhances patient engagement in neurological disorder rehabilitation and daily activities [85, 86]. However, no significant effects on pain catastrophizing have been observed, suggesting that while PBMT positively influences movement-related fear, its impact on cognitive pain-processing mechanisms remains uncertain [41, 45]. The potential mechanisms underlying these psychological benefits include PBMT-induced modulation of cerebral blood flow [87, 88, 89] and cortical excitability [90, 91] in brain regions associated with pain perception and autonomic regulation [38, 92, 93]. PBMT has also been shown to improve key physiological parameters, particularly muscle elasticity [42, 45] and sleep quality [44, 94]. Studies report significant reductions in muscle stiffness following PBMT [45], indicating enhanced tissue flexibility and relief of muscle tension [95, 96, 97], both commonly impaired in Fibromyalgia patients [42]. Furthermore, PBMT has demonstrated potential in alleviating sleep disturbances, with research indicating improvements in sleep quality and circadian rhythm regulation [44, 98]. These findings are consistent with evidence supporting PBMT's role in modulating inflammatory pathways [99] and restoring autonomic nervous system balance [100].