Effect of transcranial direct current stimulation on exercise performance: A systematic review and meta-analysis

Author(s)

Machado, Daniel G. da S. ^[1] ; Unal, Gozde ^[2] ; Andrade, Suellen M. ^[3] ; Moreira, Alexandre ^[4] ; Altimari, Leandro R. ^[1] ; Brunoni, Andre R. ^[5] ; Perrey, Stephane ^[6] ; Mauger, Alexis R. ^[7] ; Bikson, Marom ^[2] ; Okano, Alexandre H. ^{[1, 8]}

Affiliation

^[1] Univ Estadual Londrina, Grad Program Phys Educ, Londrina, PR - Brazil

^[2] CUNY City Coll, Dept Biomed Engn, New York, NY 10031 - USA

^[3] Univ Fed Paraiba, Grad Program Cognit & Behav Neurosci, Joao Pessoa, Paraiba - Brazil

^[4] Univ Sao Paulo, Sch Phys Educ & Sport, Sao Paulo, SP - Brazil

^[5] Univ Sao Paulo, Lab Neurosci LIM 27, Sao Paulo, SP - Brazil

^[6] Univ Montpellier, EuroMov, Montpellier - France

^[7] Univ Kent, Sch Sport & Exercise Sci, Canterbury, Kent - England

^[8] Univ Fed ABC, Ctr Math Computat & Cognit, Alameda Univ, 3 Anchieta, BR-09606070 Sao Bernardo Do Campo, SP - Brazil

• Document type: Review article
• Source: BRAIN STIMULATION; v. 12, n. 3, p. 593-605, MAY-JUN 2019.
• Web of Science Citations: 6

Abstract

Background: Transcranial direct current stimulation (tDCS) has been used to improve exercise performance, though the protocols used, and results found are mixed. Objective: We aimed to analyze the effect of tDCS on improving exercise performance. Methods: A systematic search was performed on the following databases, until December 2017: PubMed/MEDLINE, Embase, Web of Science, SCOPUS, and SportDiscus. Full-text articles that used tDCS for exercise performance improvement in adults were included. We compared the effect of anodal (anode near nominal target) and cathodal (cathode near nominal target) tDCS to a sham/control condition on the outcome measure (performance in isometric, isokinetic or dynamic strength exercise and whole-body exercise). Results: 22 studies (393 participants) were included in the qualitative synthesis and 11 studies (236 participants) in the meta-analysis. The primary motor cortex (M1) was the main nominal tDCS target (n = 16; 72.5%). A significant effect favoring anodal tDCS (a-tDCS) applied before exercise over M1 was found on cycling time to exhaustion (mean difference = 93.41 s; 95%CI = 27.39 s-159.43 s) but this result was strongly influenced by one study (weight = 84%), no effect was found for cathodal tDCS (c-tDCS). No significant effect was found for a-tDCS applied on M1 before or during exercise on isometric muscle strength of the upper or lower limbs. Studies regarding a-tDCS over M1 on isokinetic muscle strength presented mixed results. Individual results of studies using a-tDCS applied over the prefrontal and motor cortices either before or during dynamic muscle strength testing showed positive results, but performing meta-analysis was not possible. Conclusion: For the protocols tested, a-tDCS but not c-tDCS vs. sham over M1 improved exercise performance in cycling only. However, this result was driven by a single study, which when removed was no longer significant. Further well-controlled studies with larger sample sizes and broader exploration of the tDCS montages and doses are warranted. (C) 2018 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 14/10134-7 - Non invasive brain stimulation, physical exercise and reward system
• Grantee: Alexandre Hideki Okano
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 13/10187-0 - Neuromodulation and Brain Regulation of Physical Exercise
• Grantee: Alexandre Hideki Okano
• Support Opportunities: Scholarships in Brazil - Post-Doctoral