Feasibility of Noninvasive Trigeminal Nerve Stimulation During Exercise

The purpose of this study is to examine 1) effects of cutaneous electrical trigeminal nerve stimulation (eTNS) on respiratory control in healthy volunteers and 2) explore the potential of this approach to mitigate dyspnea in patients with chronic obstructive lung disease (COPD).

Arm1 - Healthy Volunteers Inclusion Criteria: * Adults aged 18-50 years * BMI 18-30 kg/m² * Ability to provide informed consent and complete study procedures in English Exclusion Criteria: * Current daytime respiratory impairment such as uncontrolled asthma, uncontrolled COPD, pneumonia, or interstitial lung disease * Use of supplemental oxygen * Pregnancy or breastfeeding * Current use of acetazolamide, Sodium-glucose cotransporter-2 (SGLT2) inhibitors, or daily opioids * History of claustrophobia or panic disorder * Metallic implants in the craniofacial or cervical region that may interfere with electrode placement or electrical stimulation * Implanted cardiac or neuroelectric device (e.g., pacemaker, implantable cardioverter-defibrillator (ICD), deep brain stimulator, vagus nerve stimulator, implanted drug pump) * Open, broken, inflamed, infected, or healing skin lesions at or near facial electrode placement sites * Resting heart rate \