Physical Activity and Anxiety Disorders: Neurobiological Mechanisms and Therapeutic Evidence — Narrative Review

Introduction: Anxiety disorders affect approximately 7.3% of the global population and remain undertreated. This narrative review synthesizes evidence on neurobiological mechanisms and therapeutic efficacy of physical activity (PA) in GAD, panic disorder, and PTSD. Materials and Methods: A narrative review was conducted using PubMed, Scopus, and Google Scholar (2005–2026). Boolean strategies: ("physical activity" OR "exercise") AND ("anxiety disorder" OR "GAD" OR "panic disorder" OR "PTSD"); AND ("BDNF" OR "endocannabinoids" OR "neuroplasticity"); AND ("HPA axis" OR "cortisol" OR "serotonin") AND ("anxiety" OR "stress"). Results: Regular PA exerts anxiolytic effects through BDNF upregulation, HPA axis normalization, endocannabinoid system activation, and serotonergic adaptation. Aerobic exercise reduces anxiety symptoms (ES 0.34–0.66). Resistance training achieves GAD remission (NNT=3). HIIT produces rapid symptom reduction. Aerobic exercise attenuates CCK-4-induced panic attacks. Yoga demonstrates the greatest cortisol reduction among exercise modalities. Conclusions: PA is an effective adjunct intervention for anxiety disorders, supporting integration into clinical protocols alongside pharmacotherapy and psychotherapy. Exercise prescription should consider modality, intensity, and patient characteristics.