Effects of Progressive Aerobic Training on Executive-Reward Network Connectivity and Symptoms of Internet Gaming Disorder: Randomized Controlled Trial.

Background: Internet gaming disorder (IGD) causes neurocognitive deficits and brain dysfunction. Progressive aerobic training (PAT) seems more practical. However, its effect on IGD and the underlying neural mechanism remains unclear. Objective: This preregistered, randomized controlled, single-blind study examined the efficacy of a novel non-pharmacological intervention by elucidating the neurocognitive mechanisms in IGD. Methods: A total of 72 participants with IGD (meeting the DSM-5 criteria for IGD, Internet Addiction Test [IAT] score >50, and no comorbid conditions) were recruited and randomly assigned to a PAT group (received 12 weeks of PAT with the intensity dynamically adjusted based on real-time performance) or a free training (FT) group (completed sessions of equal duration but without a progressive structure, allowing free choice of exercise mode and intensity). No intervention-related adverse events were reported. Sixty-four participants completed the experiment (PAT: 33; FT: 31), including pretreatment and posttreatment functional magnetic resonance imaging scans and 20 PAT sessions in a month. Regional homogeneity and degree centrality are calculated; the overlapping brain regions were used as seed points for functional connectivity (FC) analysis. The correlation between FC and behavioral data and neurotransmitters was also evaluated. Results: The PAT group demonstrated a significantly greater reduction in IAT scores compared to the FT group (t32=4.333, Pbonf<0.001, Cohen d=0.754, 95% CI 0.362-1.137), accompanied by a specific reduction in game craving within the PAT group (t32=2.278, Pbonf=0.03, Cohen d=0.397, 95% CI 0.045-0.851]). FC analysis revealed that PAT significantly enhanced FC within the executive control network (ECN), increasing connectivity between the right medial superior frontal gyrus (R-mSFG) and key regions, including the left postcentral gyrus (F1, 62=7.95, P=.006), bilateral superior parietal gyrus (right: F1, 62=5.68, P=.02; left: F1, 62=8.85, P=.004), and left inferior frontal gyrus (F1, 62=11.37, P=.001). PAT also strengthened ECN-reward network (RN) integration, enhancing FC between the R-mSFG and bilateral insula (right: F1, 62=11.41, P=.001; left: F1, 62=7.94, P=.006) and left substantia nigra (F1, 62=10.60, P=.002). These neural changes were behaviorally relevant, as pretest game craving positively correlated with post-intervention FC strength between the R-mSFG and left postcentral gyrus (r=0.36, P=.04, 95% CI 0.02-0.63) and right precentral gyrus (r=0.40, P=.02, 95% CI 0.07-0.65). Furthermore, the FC changes were significantly associated with cannabinoid (CB1) (P=.003) and metabotropic glutamate (mGluR5) receptor distributions (P=.005). Conclusions: This study demonstrates the efficacy of a progressive and adaptive PAT intervention in reducing IGD severity, moving beyond static protocols by dynamically tailoring intensity to individual performance. The therapeutic effect may be mediated by modulating the functional connectivity between the ECN and the RN, potentially enhancing top-down control. These results, supported by the correlation between FC, behavior, and neurotransmitter systems, indicate that PAT represents a promising non-pharmacological intervention approach worthy of further investigation.