Feasibility of Noninvasive Trigeminal Nerve Stimulation During Exercise

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 \<60 Beats Per Minute
• History of seizure disorder or epilepsy

Arm 2 -COPD

Inclusion Criteria:

• Adults aged 40-75 years
• Confirmed diagnosis of COPD by spirometry (post-bronchodilator Forced Expiratory Volume (FEV1) /Forced Vital Capacity (FVC) \<0.70) or provider documentation in medical records
• Modified Medical Research Council (mMRC) dyspnea grade ≥2
• Stable COPD (no exacerbation requiring hospitalization, systemic corticosteroids, or antibiotic therapy within the preceding 6 weeks)
• On stable COPD therapy for at least 4 weeks prior to enrollment
• Ability to provide informed consent and complete questionnaires in English
• Resting Peripheral Capillary Oxygen Saturation (SpO₂) ≥88% on room air or prescribed supplemental oxygen

Exclusion Criteria:

• Unstable cardiovascular disease (e.g., unstable angina, decompensated heart failure, recent MI within 6 months, uncontrolled arrhythmia) or peripheral vascular disease
• Patients with cardiovascular disease, including chest pain, heart failure, and aortic stenosis
• Resting heart rate \<60 BPM
• Implanted cardiac or neuroelectric device (e.g., pacemaker, ICD, deep brain stimulator, vagus nerve stimulator, implanted drug pump)
• Metallic implants in the craniofacial or cervical region that may interfere with electrode placement or stimulation
• Open, broken, inflamed, infected, or healing skin lesions at or near facial electrode placement sites
• Active trigeminal neuralgia or other cranial neuropathy
• History of seizure disorder or epilepsy
• Severe or uncontrolled psychiatric disorder (e.g., psychosis, severe untreated anxiety or panic disorder) that would impair the ability to participate
• Pregnancy or breastfeeding
• COPD exacerbation requiring hospitalization, systemic corticosteroids, or antibiotics within the preceding 3 months
• Musculoskeletal pain, injury, or any other condition that precludes the use of a stationary bike for Cardiopulmonary Exercise Test (CPET)
• Any condition that, in the opinion of the investigator, would compromise participant safety or data integrity