# 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
#### 3.1.2 Assessment and Effects of Physical Exercise on Anxiety and Stress
While Yoga achieved greater significance in its results (\(p<0.01\)) and effect size (\(\text{g}=0.88\)), this reduction in anxiety levels was not found to be significantly greater than that of standard therapy (\(p=0.09\)) [71]. The observed benefits of mind-body disciplines for individuals with SUD may stem from their focus on meditation, connection, and the balance between body and mind. These practices emphasize breathing combined with movement techniques, potentially contributing to reduced heart rate and blood pressure (BP). This, in turn, activates the parasympathetic branch of the autonomic nervous system, inducing a reduction in anxiety or stress levels [73; 74]. Regarding aerobic exercise, the most recent meta-analysis reported a moderate effect on anxiety reduction compared to standard therapy (SMD = \(-\)0.73; Z = \(-\)2.29; \(p<\) 0.05), although it showed a non-normal distribution [22]. Another study, which implemented a moderate-intensity aerobic exercise program (65-75% of maximum heart rate (HRmax)), found significant reductions in anxiety levels compared to the control group (F(1,29) = 59.59, \(p<\) 0.01, \(\eta^{2}\) = 0.67), as well as pre-intervention values (F(1,29) = 72.38, \(p<\) 0.01, \(\eta^{2}\) = 0.71), as measured using the Self-Rating Anxiety Scale (SAS) [43]. Similarly, in other studies, such as [PERSON] et al. (2023) [67], aerobic exercise demonstrated an acute effect in reducing anxiety levels significantly. These reductions were measured by one, two, and four hours post-exercise using a visual analog scale (VAS), where 0 indicates no anxiety and 10 indicates extreme panic. However, results were inconsistent in mid-term interventions (lasting 6 to 12 weeks) [43; 53; 71], with only one study reporting reductions in anxiety levels following a 12-week aerobic exercise program [43]. Another study implementing an aerobic exercise program [53], specifically on a treadmill, noted that the assumption of normality was not met. The intervention group did not achieve significant reductions in anxiety (\(p=0.81\); r = 0.06), although reductions in stress were significant (M = \(-\)5.60 [\(-\)8.47, \(-\)2.79]; \(p<\) 0.01; \(\eta^{2}\) = 0.48). Additionally, combining cardiovascular training with strength exercises has demonstrated significant effects in reducing anxiety [13; 16; 19], even with shorter durations (8 weeks) compared to aerobic exercise programs. Duration, Frequency, and Intensity of Physical Exercise for Reducing Anxiety and Stress in Individuals with SUD  
Regarding the duration and frequency of programs, session durations typically range from 60 to 90 min, with a frequency of 3 to 5 sessions per week and lasting from 8 to 24 weeks in total. In the reviewed interventions, those with a minimum frequency of three weekly sessions lasting one hour and a total duration of at least 12 weeks showed the most consistent results in reducing anxiety and stress compared to standard therapy [26; 43; 50; 70; 71; 72]. These effects were similar to those observed in previously mentioned interventions [19; 38; 51; 54; 75]. Studies that only met one of these conditions [19; 38; 51; 53; 70; 72; 75] showed a greater variability in results. Only two studies fulfilling either a program duration of 24 weeks of moderate-intensity aerobic exercise or a minimum weekly frequency of three sessions combining aerobic and strength exercises reported significant reductions in anxiety levels [70; 75]. In contrast, the most recent meta-analysis [22], which did not differentiate between activity types, found no significant reductions in anxiety levels as a result of interventions. However, longer-duration interventions showed a larger effect size (SMD = \(-\)1.30; Z = \(-\)1.94; \(p=\) 0.05). Interestingly, interventions with fewer than 40 total sessions (SMD = \(-\)0.49; Z = \(-\)2.93; \(p<\) 0.01) and sessions lasting less than one hour (SMD = \(-\)0.70; \(Z=-\)4.07; \(p<\) 0.01) were associated with significant benefits for anxiety reduction.