## 4 Discussion
In studies with patients with heart failure, the NT Pro-BNP levels can be lowered with supervised exercise training [30]. Thus, considering the present study's results, a moderate level of PA could be the most beneficial for this variable in HTRs, since HTRM expressed the lowest NT pro-BNP values. Considering the functional assessment, a common trend was identified for the SRT, BST, FBT, TUG, and 10 MWT; engaging in PA graded as high-level enables HTRs to express performance levels in these outcomes comparable to those seen in S. The 10 MWT's results merge special consideration since the gait speed has been shown to be an indicator of disability [31], health care utilization [32], and survival [33] in older adults. Thus, it is suggested a high level of PA is recommended for this aspect of the health of HTRs. Finally, regarding the SF-36 questionnaire (complementary assessment), no differences among groups in terms of mental health were observed. However, differences were detected in physical health between S and HTRL, as well as between HTRH and HTRL. These findings suggest that engaging in graded high-intensity physical activities may foster a self-perceived state of physical health among HTRs, akin to that of S.  
Analyzing results of the primary outcomes within this study globally, it becomes evident that HTRs engaging in high levels of PA exhibit a healthier status compared to those practicing moderate or low levels of activity. Remarkably, in some variables, patients with high PA levels even outperform to healthy sedentary individuals. Echoing this trend, the secondary variables follow a similar pattern, where heightened degrees of PA seem to be linked to better evaluation outcomes. The results of this study can be applied to the rehabilitation process of HTRs. Firstly, the weekly level of PA for HTRs should be high (according to the IPAQ's criteria). This level of PA should be achieved by practicing at least three days per week, although more days could be used (also according to the IPAQ's criteria). The recommendations of [PERSON] et al. (2021) [9] for the planning and execution of exercise training after heart transplantation should be considered when making this decision, including the current clinical condition, the individual comorbidities, and possible transplant-related complications of the patients. Secondly, the topics of the supervised exercise for HTRs could be all those that can improve cardiovascular condition, neuromuscular condition, basic blood parameters, functional mobility condition, and quality of life of the patients. Finally, the tests used in this study to assess the health status of the patients might be also used to evaluate the effects of the exercise on HTRs and as clinical outcomes for them. Additionally, the test results of the present study on HTRs with a high level of PA might serve as benchmarks. This study has limitations: Firstly, there are significant differences in the number of men and women of the groups as well as in the mean age of the members of the groups. However, given this study's sample size, the results can be considered a valid reference for both sexes. Secondly, the PA levels of participants were assessed through self-reported measures as the IPAQ-L. However, the IPAQ has been widely used in numerous epidemiological studies globally and has undergone extensive validation in various populations, and its widespread use allows for comparability with the existing literature, promoting a more comprehensive understanding of PA patterns across different cohorts. And finally, while this study includes a variety of outcome measures, there may be other relevant factors affecting the health status of heart transplant recipients that were not considered (e.g., dietary habits, psychological factors, and social support could influence outcomes but are not explicitly addressed).