# Effects of Physical Exercise on Substance Use Disorder: A Comprehensive Review
## 3 Results
### Assessment and Impact of Physical Exercise on the Quality of Life of Individuals with SUD
#### 3.1.1 Assessment and Effects of Physical Exercise on Depression
However, most programs with a frequency of at least three weekly sessionsover durations ranging from 8 to 24 weeks (24 to 120 total sessions) reported significant improvements in reducing depression [26; 43; 54; 58; 59; 60]. In the latest meta-analysis, which divided interventions into those lasting more or less than 12 weeks, both durations led to significant reductions in depression. However, the effect size was greater in interventions lasting at least 12 weeks (SMD = \(-\)0.83; Z = \(-\)2.55; \(p\) = 0.01), although the homogeneity criterion was not met (I\({}^{2}\) = 86.9%; \(p\) < 0.01). The same study found differences in the total number of sessions, with programs involving at least 40 sessions reporting significant reductions and a large effect size (SMD = \(-\)0.80; Z = \(-\)2.95; \(p\) < 0.01) [22]. Similarly, moderate-intensity aerobic exercise programs, with frequencies of three weekly sessions over 12 weeks, appear to yield the most significant improvements in depressive states. However, it is worth noting that some studies [53] have achieved improvements in depression (albeit not as substantial) with shorter durations or lower frequencies. This suggests the importance of individualizing physical exercise programs for individuals experiencing this issue, tailoring interventions to their needs, capabilities, and limitations. Regarding intensity in the recent literature, studies implementing moderate-intensity interventions have spanned between 6 weeks [53] and 12 weeks [43; 61], typically involving aerobic exercise. There is a dichotomy in the measurement methods between the SDS and BDI. Significant reductions compared to control groups were observed in five out of six articles examining the relationship between moderate intensity and depression. Similarly, in the latest published systematic review and meta-analysis, moderate-intensity exercise reported a moderate effect on improving depression compared to standard therapy (SMD = \(-\)0.64; Z = 5.72; \(p\) < 0.01) [45]. Other interesting results support physical exercise as a complementary treatment to traditional approaches for managing depression. For instance, [PERSON] et al. (2015) demonstrated that an 8-week intermittent, moderate-intensity exercise program, consisting of three weekly sessions, was effective in reducing multiple psychological symptoms, including depression, in methamphetamine-addicted patients [19]. Regarding high-intensity programs in the literature focused on depression improvement, only the study by [PERSON] et al. (2020) [62] was identified. This study examined the effects of a high-intensity interval training program on hormonal levels (cortisol, insulin-like growth factor 1, interleukin 17, and interferon gamma) and psychological parameters (HRSD) in opioid-addicted patients. Significant improvements were observed in HRSD scores (\(p\) < 0.01) compared to the control group after a program lasting just 21 days. In the most recent systematic review and meta-analysis, high-intensity exercise also showed better outcomes in depression improvement compared to standard therapy (SMD = \(-\)0.25; Z = 2.51; \(p\) = 0.01) [45]. In conclusion, physical exercise is an effective intervention for reducing depression in individuals with SUD. Regarding the optimal type and dose, moderate-intensity aerobic exercise has shown the most significant effects compared to other intensities (\(p\) < 0.05) [45]. Interventions comprising three weekly sessions over 12 weeks have produced the most consistent results for improving depression, reaffirming its utility as a complement to conventional therapy.