## 4 Discussion  
Our results have shown a similar influence of combination of exercise and the Mediterranean-like diet with the gold standard of OSAS therapy, in terms of body composition parameters, antioxidant and cardiovascular biomarkers, and sleep quality. Regarding cardiovascular profile, it should be noted that all participants were classified as obese or overweight, based on their BMI and body fat percentage. It is important to take into account body fat percentage, as BMI is a rough index of energy deposition but is subjected to body build and proportions [37]. Body fat percentage consists of a more accurate indicator and is independently associated with cardiovascular risk [40; 41]. In line with body fat percentage follows visceral fat percentage, which has been shown to be cardinal for systemic metabolic derangements [42]. In our study, significant differences were observed in terms of Lp(a) and visceral fat percentage, along with several oxygenation (ANRO\({}_{2}\) and ODI) parameters after 12 weeks of unsupervised rehabilitation program and dietary modifications. Abnormal high levels of Lp(a), a highly atherogenic lipoprotein associated independently with CVD [43], are found in OSA patients [44]. Concomitantly, increased visceral fat has been found to serve as an additional factor for cardiovascular risk [45]. Although the effect of CPAP alone has been found beneficial for overall lipticmic profile [44], this was the first study to establish an association with Lp(a), too. However, the efficiency of both exercise and the Mediterranean diet in lowering Lp(a) have been well documented [46; 47]. Notably, in our patients, baseline levels were within normal range. Similarly, in line with published literature, the percentage of visceral fat was significantly lower and more pronounced in the non-CPAP group, in which lifestyle interventions were implemented [48]. In fact, the non-CPAP group exhibited a better compliance with a Mediterranean-like diet, as mirrored by their significant MedDietScore increase. A fundamental, 10-year, large cohort study and its 20-year prospective approach in estimating incidence of hypertension have highlighted the importance of a Mediterranean-like diet in controlling cardiovascular risk [49; 50]. Although non-significant, other parameters of body composition demonstrated a trendline of change like reduction of body fat, as well as an increase in muscle mass and chest diameter. These results could potentially signify that exercise and the Mediterranean diet alone could fundamentally contribute as therapeutic modalities for OSA, by optimizing body composition, which has been incriminated for OSA severity and its complications [51]. By combining these lifestyle interventions, results were significantly comparable in both groups. Concomitantly, oxygenation parameters followed a similar but non-significant trendline of improvement in both groups, in line with published data regarding the effects of CPAP and exercise in OSA [18; 52]. The results were also reflected by improvements in physical indices, like 6 MWT and estimate oxygen uptake in both groups. Physical exercise included mainly aerobic training. Aerobic capacity is a strong health predictor that represents the potential cardiorespiratory reservoir, which has been associated with the reduction oxidative stress and inflammation markers and is found hindered in OSA [53; 54]. This could be partly attributed to autonomic incapability of adapting to exercise, as assessed indirectly by heart rate variability before and after exercise in OSA [55]. Our study showed that exercise offered an amelioration in autonomic dysfunction as well, by exhibiting significant differences in adaptation of HR after recovery, when comparing the two groups. Similar results were exhibited by [PERSON] et al. who incorporated exercise for the same time interval in OSA patients and correlated such improvement of heart rate after recovery with oxygen saturation change [56].