Adeniyi MJ, Awosika A. Cortical arousal and autonomic regulation: The role of cold vs tepid caffeinated beverages during prolonged orthostasis. World J Methodol 2026; 16(2): 115219 [DOI: 10.5662/wjm.v16.i2.115219]
Corresponding Author of This Article
Mayowa J Adeniyi, PhD, Assistant Professor, Department of Physiology, University of Rwanda, College of Medicine and Health Sciences, KG 11 Ave, Kigali 01000, Rwanda. 7jimade@gmail.com
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Medicine, General & Internal
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Jun 20, 2026 (publication date) through Apr 23, 2026
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World Journal of Methodology
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Adeniyi MJ, Awosika A. Cortical arousal and autonomic regulation: The role of cold vs tepid caffeinated beverages during prolonged orthostasis. World J Methodol 2026; 16(2): 115219 [DOI: 10.5662/wjm.v16.i2.115219]
World J Methodol. Jun 20, 2026; 16(2): 115219 Published online Jun 20, 2026. doi: 10.5662/wjm.v16.i2.115219
Cortical arousal and autonomic regulation: The role of cold vs tepid caffeinated beverages during prolonged orthostasis
Mayowa J Adeniyi, Ayoola Awosika
Mayowa J Adeniyi, Department of Physiology, University of Rwanda, Kigali 01000, Rwanda
Ayoola Awosika, Department of Family Medicine, University of Illinois College of Medicine Peoria, Bloomington, IL 61601, United States
Co-corresponding authors: Mayowa J Adeniyi and Ayoola Awosika.
Author contributions: Adeniyi MJ and Awosika A conceptualized the study, designed the methodology, conducted the investigation, performed formal analysis, and drafted and reviewed the original manuscript; they contributed equally to this article, and they are the co-corresponding authors of this manuscript; All authors approved the final version of the manuscript.
Institutional review board statement: This study was approved by the Medical Ethics Committee of Edo State University Uzairue, approval No. EDO35-4.
Clinical trial registration statement: Not applicable.
Informed consent statement: Consent was obtained by all participants in this study. The consent form was approved by the Departmental Ethical Committee, Physiology department College of Medical Sciences Edo State University Uzairue, Edo state.
Conflict-of-interest statement: All authors report no relevant conflicts of interest for this article.
CONSORT 2010 statement: The authors have read the CONSORT 2010 Statement, and the manuscript was prepared and revised according to the CONSORT 2010 Statement.
Data sharing statement: Not applicable.
Corresponding author: Mayowa J Adeniyi, PhD, Assistant Professor, Department of Physiology, University of Rwanda, College of Medicine and Health Sciences, KG 11 Ave, Kigali 01000, Rwanda. 7jimade@gmail.com
Received: October 11, 2025 Revised: November 12, 2025 Accepted: January 7, 2026 Published online: June 20, 2026 Processing time: 194 Days and 13.6 Hours
Abstract
BACKGROUND
The interplay between caffeine ingestion, beverage temperature, and orthostatic stress on cortical arousal and autonomic regulation remains poorly understood. Understanding these distinctions is critical in identifying non-pharmacologic strategies for mitigating orthostatic intolerance, presyncope, and fatigue. Furthermore, electroencephalogram (EEG) biomarkers may provide objective insights into cortical-autonomic coupling during prolonged standing. This emerging perspective offers a novel translational pathway for optimizing performance and well-being in both clinical and occupational settings.
AIM
To investigate the effect of ingesting cold and tepid caffeinated beverages on brain waves during prolonged orthostasis.
METHODS
Thirty-six male individuals, averaging 20 years old, who satisfied the inclusion criteria were selected using respondent-driven sampling. Caffeinated beverages containing 10-12 mg of caffeine per 100 mL at 10 °C (cold) or 37 °C (tepid) were used for the study. Baseline EEG and pulse rate in a sitting position were recorded. Orthostasis was defined as standing upright from a sitting position and lasting 20 min. An EEG was conducted using PowerLab 26T.
RESULTS
Pulse rate was significantly elevated by orthostasis when compared with the baseline. Cold caffeinated beverages decreased the alpha/beta ratio and increased beta wave frequency when compared with tepid caffeinated drinks. Orthostasis also increased beta wave frequency but decreased alpha wave frequency and the alpha/beta ratio when compared with baseline. However, orthostatic individuals administered tepid caffeinated beverage showed no significant difference in the alpha/beta ratio with orthostatic individuals administered a cold caffeinated beverage.
CONCLUSION
Neither cold nor tepid caffeinated beverages altered EEG responses to prolonged orthostasis; caution is advised during standing, particularly for elderly individuals and patients prone to orthostatic syncope or autonomic disorders.
Core Tip: Electroencephalogram biomarkers highlight temperature-dependent differences in neurophysiologic adaptation and resilience to orthostatic stress. These findings underscore the potential of beverage-based interventions as simple, non-pharmacologic strategies to mitigate presyncope and fatigue. A significant finding from this study was the insignificant difference in alpha/beta ratio between orthostatic individuals administered tepid caffeinated beverage and orthostatic individuals who were given cold caffeinated beverages despite the fact that orthostatic individuals who ingested tepid caffeinated beverages exhibited higher beta wave frequency when compared with orthostatic individuals administered cold caffeinated beverages.
