The goal of this interventional study is to understand how regular yogic breathing practice, particularly a slow resistive yogic breathing technique called Ujjayi, would benefit individuals between the ages of 18 and 60 with spinal cord injuries. Previously yogic breathing has shown to improve respiratory function and sleep- we'd like to explore this further.
The main questions this study aims to answer are:
* How does Ujjayi breathing affect breathing patterns in individuals with spinal cord injuries? * How does Ujjayi breathing affect lung function in individuals with spinal cord injuries? * How does Ujjayi breathing affect the part of the nervous system responsible for ventilatory control in individuals with spinal cord injuries? * How does Ujjayi breathing affect ventilatory perfusion (how well air and blood flow match in the lungs for efficient gas exchange) in individuals with spinal cord injuries? * How does Ujjayi breathing affect sleep quality in individuals with spinal cord injuries?
Participants will undergo six weeks of training in Ujjayi breathing. Before and after this period, they will visit the lab for measurements of blood pressure, pulse, blood oxygen levels, and breathing. They will also perform several tests:
* Pulmonary function testing to assess lung capacity and respiratory muscle strength. * Pace breathing frequency to four pre-recorded audio files at various breathing rates. * Breathing exercises involving higher levels of carbon dioxide for a short time. * Breathing exercises involving lower levels of oxygen for a short time. * At-home sleep evaluation.
Between the two laboratory testing sessions, participants will practice yogic resistance breathing (Ujjayi breathing) for six weeks.
Spinal cord injury
American Spinal Injury Association Impairment Scale (AIS) score of A, B, or C
Aged 18-60 years
Wheelchair user
Resting blood pressure of >140/90 mmHg
Current use of tobacco or cardioactive medications (except medication to support blood pressure)
Significant arrhythmia
Bleeding disorder
Single group
Ujjayi Yogic Breathing
BehavioralParticipants will undergo 6 weeks of resistive yogic breathing (Ujjayi) upon exhalation (first three weeks) and upon inhalation and exhalation (second three weeks).
Ventilatory pattern after regular Ujjayi breathing
Ventilatory patterns measured as rate and regularity by breathing belts (pneumobelts). A normal respiratory rate for an adult at rest is 12 to 18 breaths per minute.
Pulmonary function after regular Ujjayi breathing
Pulmonary function measured by spirometry, maximal voluntary ventilation, and maximum inspiratory and expiratory pressures. Results will be reported as forced vital capacity (FVC), Forced Expiratory Volume in 1 second (FEV1), FEV1/FVC ratio, Peak Expiratory Flow (PEF), and Forced Expiratory Flow (FEF) 25%-75%. An absolute range cannot be provided as it depends on various factors such as injury level, completeness of injury, age, race, and sex. In healthy adults, MVV is typically around 120-170 liters per minute (L/min).
Central and peripheral chemosensitivity after regular Ujjayi breathing
The Read rebreathing method assesses neural drive to breathe and CO2 sensitivity (central chemosensitivity). A three-way valve connects the breathing circuit to room air or 95% O2-5% CO2. Subjects exhale to functional residual capacity, then rebreathe until PETCO2 reaches 55 mmHg, they can't continue, SPO2 drops below 95%, or 10 minutes elapse. Peripheral chemosensitivity uses brief exposures to hypercapnic (10% CO2, 21% O2) or hypoxic gas (pure nitrogen). Ventilatory response is measured over up to 30 seconds, followed by room air. Each test takes about 15 minutes. Tests are conducted seated and supine. Chemosensitivity is measured by plotting ventilation against pulmonary gas levels.
Ventilatory perfusion after regular Ujjayi breathing
Ventilatory perfusion will be calculated from mixed expired and end tidal CO2 measures. The V/Q ratio in healthy lungs is close to 1- this means that ventilation (V) matches perfusion (Q) almost perfectly in well-ventilated alveoli. Certain pathologies could increase or decrease the V/Q ratio.
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