Table 1.
List of breathing pattern components and common abbreviations.
| Abbreviation | Variable (units) | Definition |
|---|---|---|
| BP | Breathing pattern | Differential trait and state-dependent control of breathing rhythm and mechanics |
| BR | Breathing rate (bpm) | Respiratory frequency; number of breaths taken per minute |
| Dc | Duty cycle, breath ratio (%) | Breath timing; relative percentage of inhale time to the complete breath cycle (TI/TB in %) |
| EELV | End-expiratory lung volume | Volume of the lungs at the end of an expiration |
| EID | Exercise-induced dyspnoea | Excessive perceived breathlessness during activity |
| EILV | End-inspiratory lung volume | Volume of the lungs at the end of an inspiration |
| FR | Flow reversal | Instant of breath switching; e.g., from inhale to exhale or exhale to inhale |
| LOV | Lung operating volume (%) | Mean diaphragm position at a given tidal volume (mean of EELV + EILV as % of TLC) |
| LRC | Locomotor-respiratory coupling (steps:breath) | Synchronization between flow reversal and movement; e.g., running footstrike |
| RV | Reserve volume (l) | Amount of air that remaining in airway and lungs after maximal expiration |
| TB | Breath cycle time (s) | Total breath time from inspiration to next inspiration (TI + TE) |
| TE | Exhale time (s) | Exhale duration during one breath cycle |
| TI | Inhale time (s) | Inhale duration during one breath cycle |
| TLC | Total lung capacity (l) | Total amount of air present in lungs after maximal inspiration |
| TLD | Thoraco-lumbar depth (%) | Ratio of thorax to abdominal expansion contributing to total tidal volume |
| VC | Vital capacity (l) | Total amount of air exhaled after maximal inspiration (TLC-RV) |
| VT | Tidal volume (l), depth | Breathing depth; total amount of air inspired during one breath cycle |
| VD | Ventilatory dead space (l) | Sum of airway volumes which do not contribute to gas exchange |
| VE | Minute ventilation (L/min) | Quantity of air breathed per minute |
| VO2 | Oxygen consumption (L/min) | Oxygen consumption; difference between oxygen inspired and oxygen expired in a unit of time |
| WOB | Work of breathing | Metabolic energy demand of ventilation |
| - | Thoraco-lumbar coordination (s) | Breathing coordination; time lag between thoracic and abdominal flow reversal |
| - | Ventilatory drive (l/s) | Total output of ventilatory pump; mean inspiratory flow rate (VT/TI) |
| - | Ventilatory efficiency | Ventilatory pump response to increasing demands, frequently measured as VE/VCO2 slope |