## 4 Discussion  
Recently, considerable interest has been given to important and frequent sequela after SARS-CoV-2 infection, represented by a chronic post-infectious syndrome, called Long-COVID syndrome, which can occur in hospitalized and non-hospitalized patients [24]. Post-COVID syndrome presents with non-specific symptoms, most commonly characterized by diffuse musculoskeletal pain, fatigue, headache, dyspnea, anosmia, and memory impairment, which are FM-like disorders [6; 24]. This syndrome occurs more frequently in patients with a more severe form of COVID-19, including a higher hospitalization rate and more repeated supplemental oxygen treatment [6; 24]. SARS-CoV-2 virus is highly immunogenic, which is why it can induce a significant post-viral musculoskeletal syndrome [13; 24] underlying which could be endothelial or neuromuscular lesions, immunological imbalance and inflammation. Regarding the latter, it is interesting to note that some of the pro-inflammatory cytokines involved in COVID-19 and PACS manifestations, such as interleukin (IL) -1 and IL-6,2 39, may con- tribute to the FM pathogenesis [6]. The therapeutic management of patients with post-COVID syndrome remains rather controversial, as to date no pharmacological treatment has been shown to improve or mitigate post-COVID syndrome symptoms [10]. Data in the literature suggest that rehabilitation may play an important role in the treatment of post-COVID syndrome by performing low-intensity aerobic exercises with gradual increase in difficulty, according to the patient's tolerance, as well as breathing exercises aimed at improving respiratory muscle efficiency, especially of the diaphragm [25]. Some studies have shown that a personalized multidisciplinary rehabilitation approach, involving breathing, musculoskeletal system and psychological interventions, is able to improve symptoms such as pain, fatigue, endurance and anxiety, but not depression [26; 27; 28]. In light of the well-known similarities between post-COVID syndrome and FM, during our investigation we evaluated the effectiveness of physical exercise associated with LAC in patients with post-COVID syndrome in terms of improvement of musculoskeletal pain, dyspnea, functional capacity, quality of life and depressive symptoms. Our study was the first to evaluate drug therapy with ALC in the management of patients with post-COVID syndrome. We have observed that physical exercise alone is shown to improve functional capacity and quality of life. However, if it is combined with ALC therapy, an improvement in musculoskeletal pain and depression is also achieved. Finally, by comparing the variations of the different outcomes examined, we observed how physical exercise, associated with ALC supplementation, also leads to improvements in quality of life. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Characteristics** & **AT1-T0** & **\(\Delta\)T2-T0** & \(p\)-Value** \\ \hline
**NRS** & 2.28 \(\pm\) 0.63 & 0.42 \(\pm\) 0.63 & \textless{}0.05 \\
**NPI** & 1.97 \(\pm\) 3.88 & 2.23 \(\pm\) 3.92 & 0.79 \\
**FIQ** & 8.7 \(\pm\) 5.72 & 6.52 \(\pm\) 2.68 & 0.07 \\
**SF-12** & 4.27 \(\pm\) 1.91 & 2.22 \(\pm\) 2.53 & \textless{}0.05 \\
**PHQ-9** & 3.19 \(\pm\) 2.04 & 1.4 \(\pm\) 1.33 & \textless{}0.05 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison of the variations in the score of the evaluation scale between the two groups. ALC also acts on the muscle level and the effectiveness of oral ALC supplementation in humans has been evaluated. A study evaluated its effectiveness in improving glucose tolerance in insulin-resistant individuals. The authors used a dosage of 2000 mg of acetyl-carnitine per os per day, observing an increase in the levels of acetylcarnitine in the resting muscle and an increase in its formation during physical activity, with consequent beneficial effects on metabolic flexibility [29].