Effects Of Resistance Exercise Training On Cerebral Blood Flow In Individuals With Major Depressive Disorder

PURPOSE: Research shows that Major Depressive Disorder (MDD) is associated with impaired cerebral blood flow (CBF). Resistance Exercise Training (RET) may improve CBF in healthy adults but RET’s effect on CBF in adults with MDD is unknown. The purpose of this pilot study was to explore the effects of 16 weeks of RET on middle cerebral artery (MCA) mean blood velocity and cerebrovascular reactivity (CVR) in adults with MDD. METHODS: Nine untrained adults with MDD (confirmed via Structured Clinical Interview for DSM-5) completed a 16-week full-body RET pilot intervention twice per week performing 3 sets of 8-12 repetitions of ten exercises. At baseline, midpoint, and final visits, CBF was assessed as mean blood velocity and conductance of the MCA via transcranial doppler and mean arterial pressure was measured via oscillometric cuff. CVR was assessed as the average change in MCA mean blood velocity expressed relative to change in end-tidal CO2 immediately following 8, 20-sec breath holds. The effects of RET on CBF from baseline to midpoint and final were described and evaluated via effect sizes (Hedges’ g) and paired t-tests. RESULTS: There were small, nonsignificant increases in MCA velocity (median [M] = 51.5, 55.4, 54.1 cm/s for baseline, 8-, and 16-wk; g = 0.07-0.32, p = 0.31-0.82) and conductance (M = 0.55, 0.59, 0.61 cm/s/mmHg for baseline, 8-, and 16-wk; g = 0.16-0.42, p = 0.19-0.62) during the intervention from baseline. There were small, nonsignificant decreases in MCA CVR from baseline [M = 1.25] to midpoint [M = 1.03, g = -0.22, p = 0.49] and final visit [M = 1.0, g = -0.13, p = 0.67]. CONCLUSIONS: These preliminary results suggest metrics of CBF may change in adults with MDD across 16 weeks of RET and may be a mechanistic target that warrants further research. Future research investigating the effects of RET on CBF in MDD with larger controlled trials is warranted.