## 4 Discussion
This aligns with previous findings suggesting that, among patients with autoimmune diseases, the anticipated changes in inflammation biomarkers resulting from exercise are modest at best [59]. Hence, a reduced effect of exercise on disease activity is expected. Notably, prior research has shown that patient-reported symptoms, which relate to systemic activity, are associated with improved health-related quality of life in individuals with pSS [60]. This finding suggests that since exercise was ineffective in reducing disease severity, it likely also did not have a direct impact on the quality of life. The effects of current pharmacological therapies aimed at alleviating the symptoms of this disease are limited, primarily due to its unknown and complex etiology, with potential treatment targets for disease severity still requiring further research [61]. In this context, it appears that exercise should not be regarded as a more viable option than the existing prescribed drug therapies. On the other hand, the reviewed studies highlighted a positive impact of exercise on physical function, which is particularly noteworthy given that functional status is often impaired in individuals with pSS [16]. This finding aligns with previous research suggesting that exercise can significantly benefit the physical functioning of patients with rheumatological diseases [62]. Based on the analyzed data, it can be hypothesized that this improvement may stem from increases in fitness levels associated with engaging in physical activity, as this factor is closely linked to the prevention of functional decline [63]. In this regard, it is worth noting that those who experienced a greater increase in their fitness levels compared to their peers undergoing standard treatment showed more pronounced improvements. Similarly, exercise has also been shown to be effective in reducing the impact of fatigue. This is a significant finding, as patients with pSS often report that fatigue is their most challenging and burdensome symptom to manage [64]. Other published reviews on the effects of exercise in autoimmune and rheumatic diseases have also reported positive outcomes, particularly in reducing fatigue levels [23; 65]. Fatigue in [PERSON]'s disease is believed to be partly driven by pro-inflammatory cytokines. Therefore, it can be hypothesized that exercise may help alleviate fatigue by reducing the concentration levels of these pro-inflammatory cytokines, as has been suggested in other conditions [66]. The obtained results support the notion that, while pharmacological treatments for fatigue have not proven effective in managing this symptom, exercise appears to be a valuable, safer, and more cost-effective option [42]. The reviewed studies that provided data on outcomes related to sleep problems and metabolic health indicated that exercise had a similar effect to standard pharmacological treatment. Similarly, exercise has been shown to yield effects akin to pharmacological therapy in individuals with movement disorders ([PERSON], 2019), and to offer comparable benefits for metabolic health when evaluated alongside standard pharmacological approaches [67]. However, the limited number of investigations available restricts the ability to draw more definitive conclusions or engage in deeper discussion. On a final note, it is important to highlight that dropouts due to health issues were reported in the exercise groups by the authors of the studies included in this review, with some cases being directly attributed to the exercise itself. This finding raises concerns about the feasibility of exercise interventions for individuals with pSS and suggests that caution should be exercised when recommending physical activity to this population. The findings of this systematic review support the use of supervised physical exercise programs, conducted 2 to 3 days per week in sessions of 30 to 60 min, as a complementary, safe, and effective intervention for patients with pSS.