Evidence summary
Multiple meta-analyses have studied the anxiolytic effects of PA in non-clinical populations and demonstrate that PA is effective at reducing anxiety symptoms in people without a diagnosed anxiety disorder. A large meta-meta-analysis of high quality randomised control trials reviewed a total of 306 studies with 10 755 participants to review the effects of physical activity in a non-clinical population and found that physical activity reduces anxiety by a significant, small effect size (SMD = -0.38; 95% CI: -0.66 to -0.11) with no significant heterogenicity across meta-analyses (I2 = 4%, P = 0.63) and had a low risk of bias for the effect (1). One meta-analysis of an update of 36 RCTs of acute exercise effects on state anxiety demonstrated a small but significant mean improvement (Hedges’ g = 0.16, Standard error, (SE) 0.06) in state anxiety in response to a single bout of exercise compared to controls (2). One meta-analysis demonstrated that reductions in anxiety symptoms for exercise programs lasting up to 12 weeks, using session duration of at least 30 mins (3). One meta-analysis of RCTs (4) found exercise could be as effective at reducing anxiety as other commonly used treatments including CBT and nearly as effective as pharmacotherapy.

Quality of evidence
A – High

Strength of recommendation
1 – Strong

Conclusion
There is consistent evidence that PA can reduce anxiety symptoms in non-clinical groups with anxiety despite not formally diagnosed as having an anxiety disorder or anxiety traits.

References
1) Rebar AL, Stanton R, Geard D, Short C, Duncan MJ, Vandelanotte C. A meta-meta-analysis of the effect of physical activity on depression and anxiety in non-clinical adult populations. Health Psychol Rev. 2015;9(3):366-78. doi: 10.1080/17437199.2015.1022901. Epub 2015 Jul 3. PMID: 25739893.
2) Ensari I, Greenlee TA, Motl RW, Petruzzello SJ. META-ANALYSIS OF ACUTE
Exercise effects on state anxiety: an update of randomized controlled trials over the past 25 years. Depress Anxiety. 2015 Aug;32(8):624-34. doi:10.1002/da.22370. Epub 2015 Apr 21. PMID: 25899389.
3) Herring MP, O’Connor PJ, Dishman RK. The effect of exercise training on anxiety symptoms among patients: a systematic review. Arch Intern Med. 2010 Feb 22;170(4):321-31. doi: 10.1001/archinternmed.2009.530. PMID: 20177034.
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4) Wipfli BM, Rethorst CD, Landers DM. The anxiolytic effects of exercise: a meta-analysis of randomized trials and dose-response analysis. J Sport Exerc Psychol. 2008 Aug;30(4):392-410. doi: 10.1123/jsep.30.4.392. Erratum in: J Sport Exerc Psychol. 2009 Feb;31(1):128-9. PMID: 18723899.