Effects of Transcranial Direct Current Stimulation on Athletic and Cognitive Performance in Normobaric Hypoxia Condition

Effects of transcranial direct current stimulation of the primary motor cortex and dorsolateral prefrontal cortex on time to exhaustion, the amplitude of muscle electromyography, perceived exertion, pleasure sensation, arousal, cognitive function, and choice reaction time after exhausting endurance activity in hypoxia

A within-subject, counterbalanced, and double-blind study. Fifteen subjects will be randomly exposed to 3 different conditions. Randomizing the situations is done via www.randomization.com.

This study is conducted at Razi University. After recruiting the subjects and their familiarization, each subject is exposed to 3 different conditions of electrical stimulation of the brain in random order and then, will perform one bout of endurance activity until exhaustion in normobaric hypoxia.

Inclusion Criteria: Aged between 18 to 30 years old Student of sports sciences, third semester or higher Reside in Kermanshah Not climbing to an altitude of more than 2000 meters in the past month Getting the certification of no prohibition of participating in the exercise Exclusion Criteria: Suffering from any cardiovascular, pulmonary, and metabolic diseases History of seizures, epilepsy, or other neurological diseases Existence of implantable devices or pacemakers in the body Tobacco and alcohol consumption Refusal to give informed consent

In this within-subject and counterbalanced study, participants will be exposed to 3 different conditions of brain stimulation including 1) Anodal stimulation of the primary motor cortex, 2) Anodal stimulation of the dorsolateral prefrontal cortex, 3) Sham stimulation (placebo effect) for 20 minutes and 2 milliamperes intensity.

Change in time to exhaustion, perceived exertion, electromyography, cognitive function, and reaction time.

In this study, the order of subjects' exposure to 3 different conditions (3 different types of electrical stimulation of the brain) will be randomized by the Latin Squares method. To do so, first using the site www.random.org, a number between 1 and 15 will be randomly allocated to each subject as an identification code. Then, the English letters A, B, and C will be assigned to the three intervention conditions and a Latin Square will be created. In this case, a Latin square with three rows and three columns is created. Finally, participants 1 to 5 will be placed in the sequence of the first row, participants 6 to 10 will be placed in the sequence of the second row, and participants 11 to 15 will be placed in the sequence of the third row.

In this double-blind study, the investigator and participants will be blinded to the type and target areas of transcranial electrical stimulation used in each session. In the present study, a Neurostim stimulator will be used to induce direct current electrical stimulation in three separate sessions and in three different modes, including 1) Anodal stimulation of the primary motor cortex (M1), 2) Anodal stimulation of the dorsolateral prefrontal cortex (DLPFC), 3) sham stimulation (Placebo effect). To do so, an individual outside the research team will be responsible for applying electrical stimulation in three test sessions. In order to blind the participants, after they sit on a special chair, the stimulator will be hidden from their view and wrapped by a cover, and the electrodes will be placed on the target areas by that individual. In order to blind the investigator, before the intervention, the investigator leaves the laboratory and returns to the test site after the termination of the stimulation time, removal of the electrodes, and turning off the stimulator. Also, in Sham stimulation mode, according to standard protocols, active current will be applied for 30 seconds in order to induce a feeling similar to active stimulation modes, and then the current is cut off and the stimulation will be deactivated.

All data are shared after the de-identification of the participants

3 months after publication

All individuals upon formal request

Data sharing requests are accepted for any purposes

To obtain any data/document, please send an e-mail to Ehsan Amiri, a faculty member at Razi University, through the following e-mail address: e.amiri@razi.ac.ir

Upon formal request, mentioning due reasons, and providing full personality details, data will be sent after 72 h via e-mail