Effect of Exercise Training on Middle Cerebral Artery Blood Flow Velocity: A Meta-Analytic Study

was to determine the effect of exercise training, higher cardiopulmonary fitness and/or physical activity history on middle cerebral artery blood flow velocity (MCAv) in healthy subjects.

Interventions investigated on healthy adults published in peer-reviewed journals up to July 2020 were searched in PubMed, Google Scholar, SID and Magiran databases. Totally, 14 studies (including on 21 interventions) comprised from those with pre- and post-intervention design (7 studies) and others with ex post facto design (7 studies) fulfilled the eligibility criteria. The random effects model was used for analysis of the data reported as Difference in Means using CMA2 software. Moreover, correlations between the effect sizes of exercise training or physical fitness level on MCAv with subjects’ age, maximal oxygen consumption, mean arterial pressure, body weight, body mass index, resting heart rate, end-tidal carbon dioxide partial pressure and also with the duration of exercise training were assessed using simple random model meta-regression.

Exercise training causes a non-significant increase of 0.569 cm/s in MCAv (p= 0.60) regardless of the subjects’ characteristics as well as the number of training weeks. Additionally, no significant correlations were observed in Meta regression assessments (p>0.05).

At present it is not possible to rely on the effects of exercise training, higher cardiopulmonary fitness and/or subjects’ exercise history to improve cerebral blood flow or prevent its reduction. However, more clinical trials are still warranted to be done in this area.