# Effects of a Short-Term Supervised Exercise Program in Women with Breast Cancer
## 4 Discussion  
To the best of our knowledge, this is the first study conducted in cancer patients where a 6-week program combining aerobic, resistance training, and stretching exercises has been implemented. Our findings suggest that despite its short duration, this program leads to improvements in quality of life and reduction in fatigue, as well as enhancement in muscle strength and functional capacity. The quality of life of participants experienced a significant improvement without any recorded adverse events, with an increase of 9.4% in the global health status, a result consistent with previous studies conducted in similar populations [23, 50, 51]. However, it is worth noting that in all these studies, the programs were of longer duration. Analyzing the results by areas and symptoms reveals encouraging outcomes. In the functioning area, there were notable improvements in role functioning (16.4%), possibly associated with gains in strength, endurance, and mobility observed at the end of our intervention and their transfer to daily activities. Emotional role improved by 20.4%, likely due to the release of serotonin and beta-endorphins during physical activity, as indicated in previous studies [52], with a positive impact on anxiety and stress. Cognitive function increased even more significantly, by 27.1%. Numerous studies support our findings, indicating that aerobic exercise leads to improvements in brain function and cognition after 6 weeks [53, 54, 55, 56]. Regarding symptomatology, significant improvements were notable post-intervention. Pain decreased by 30.8%, possibly due to the secretion of endogenous opioids and serotonin associated with physical activity. Dyspnea reduced by 53.3% as a consequence of positive adaptations resulting from aerobic training. Fatigue and insomnia decreased by 29.2% and 43.2%, respectively, possibly related to cortisol modulation due to physical exercise [57]. Anorexia also saw notable improvement, possibly caused by increased energy expenditure and nutrient demand. However, it is noteworthy that financial difficulties increased, a trend consistent with other studies in cancer patients [23], without a defined cause. Regarding fatigue, one of the most common symptoms in cancer patients [11] closely related to quality of life [18], there was a 13.2% improvement in FACIT-F and a 29.2% improvement in the fatigue-related symptoms in the EORTC QLQ C-30 questionnaire. These improvements were also observed in other therapeutic exercise programs measured \begin{table}
\begin{tabular}{c c c c c} \hline \hline  
* = significant difference between pre-exercise and post-exercise (\(p<0.05\)); M = mean \(\pm\) SD = standard deviation; CI = confidence interval.  
\end{table} 
Table 5: _Cont._with these or other instruments [23; 24; 25]. In addition to the previously mentioned aspects, we believe that physical exercise could exert a compensatory action on factors directly related to fatigue. These factors may include catabolic effects produced by tumor processes, resulting in muscle tissue loss exacerbated by the adverse effects of immunosuppression. This leads to a decrease in myofibrillar mass, alteration of aerobic metabolism, and reduced capillarization [58]. The results regarding the improvement in strength and functional capacity of the patients align with those reported in other studies [25; 39; 59]. In these studies, a combined exercise of strength and cardiorespiratory endurance was also implemented. However, the duration of those exercise programs ranged from 12 weeks to 18 months. In contrast, in this study, physical function improved with just a 6-week exercise program conducted three days a week. Thus, positive outcomes were achieved in half the time compared to other studies [25; 59]. These results may primarily be attributed to the choice of exercise program.