Exercise Induced Asthma, Exercise Induced Bronchospasm
Conditions
Brief summary
Due to the lack of studies examining the impact of inspiratory muscle training (IMT) on the severity of exercise-induced bronchoconstriction (EIB) and exercise performance, the specific aim of this study is to assess the efficacy of flow-resistive IMT on EIB severity and symptoms, short-acting beta-2-agonist medication use, operating lung volumes, respiratory and limb locomotor muscle deoxygenation during constant-load cycling exercise, exertional dyspnea, and cycling time-trial performance.
Detailed description
To the investigators knowledge, no study has been conducted assessing the impact of inspiratory muscle training (IMT) on exercise-induced bronchoconstriction (EIB) severity, exertional dyspnea, and cycling time-trial performance. A review noted that studies examining the impact of IMT on asthma have all demonstrated an increase in inspiratory muscle strength (maximal inspiratory pressure, MIP) and endurance (sustained maximal inspiratory pressure). In addition, it has been observed that the reduction in the perception of dyspnea following and during exercise leads to a reduction in short-acting beta-2-agonist (SABA) use and fewer asthma symptoms. The same review also noted the lack of data available to explain the impacts of IMT on exercise performance and tolerance in athletes with EIB. Due to the lack of studies examining the impact of IMT on the severity of EIB and exercise performance, the specific aim of this study is to assess the efficacy of flow-resistive IMT on EIB severity and symptoms, SABA medication use, operating lung volumes, respiratory and limb locomotor muscle deoxygenation during constant-load cycling exercise, femoral blood flow, exertional dyspnea, and cycling time-trial performance. It is hypothesized that eight weeks of IMT will reduce EIB's severity and symptoms, respiratory and limb locomotor muscle deoxygenation, improve operating lung volumes, and exertional dyspnea and improve cycling time-trial performance.
Interventions
DEVICEPrO2Fit Device
The flow-resistive protocol using the device requires participants to maximally inhale as hard as they can and as long as they can against a small leak (2mm diameter hole) until task failure. This records maximum inspiratory pressure (MIP) and sustained maximal inspiratory pressure (SMIP) values which will be recorded and the best is chosen for the software template by the participant to continue their training session (previously described in arm/group description). The use of the device occurs three times a week, and used for 6-8 weeks.
Sponsors
Indiana University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to 35 Years
Healthy volunteers
No
Inclusion criteria
* Male and female, between the ages of 18 to 35 years. * Required to be a competitive recreational or college athlete and have at least 1-2 years of cycling or biking experience. * Body Mass Index (BMI) of 18.5 to 28 kg/m\^2 * Considered "moderately to highly active" by the International Physical Activity Questionnaire (IPAQ). * Have clinically treated mild to moderate persistent asthma and/or exercise-induced bronchoconstriction (EIB), with a resting forced expiratory volume in 1 second (FEV1) \> 65% of predicted. * A ≥ 10% drop in FEV1 after eucapnic voluntary hyperpnea (EVH). * Prescribed short-acting β2-agonists (SABAs) by a physician. * Comfortable not taking SABA before experimental visits.
Exclusion criteria
* History of smoking or recreational smoking, cardiovascular disease, renal disease, neurological disease, and metabolic disease. * Currently taking asthma maintenance medications (e.g., corticosteroids and leukotriene modifiers) * Any injuries in the past 6 months. * Taking selective serotonin reuptake inhibitors (SSRI)'s (antidepressants and anxiety medication), attention-deficit hyperactivity disorder (ADHD) medication, and chronically consume pain medication (Aleve, Tylenol, cannabidiol (CBD), etc.). * Has had or is positive for COVID-19. * Resting blood pressure of \> 130 mmHg systolic or 90 mmHg diastolic. * Resting Pulse rate of \> 100 bpm. * Regularly consuming fish oil supplements or eating more then one fish meal per week
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Exercise-Induced Bronchoconstriction (EIB) Severity | 8 weeks | More specifically, the pre- and post-values of the percentage drop in forced expiratory volume in 1 second (FEV1) from the eucapnic voluntary hyperpnea (EVH) test before and after IMT will be measured. Percentage drop in forced expiratory volume in 1 second (FEV1) will be reported in percentages. |
| Maximum Inspiratory Pressure | 8 weeks | More specifically, the pre- to post-values of maximum inspiratory pressure (reported as cmH2O) before and after IMT will be measured. |
| Sustained Maximum Inspiratory Pressure | 8 weeks | More specifically, the pre- to post-values of sustained maximum inspiratory pressure (reported as pressure time units) before and after IMT will be measured. |
| 16-km Cycling Time-Trial Time to Completion | 8 weeks | More specifically, differences in 16-km cycling time-trial completion time (seconds) before and after IMT. |
| 16-km Cycling Time-Trial Power Output | 8 weeks | More specifically, differences in 16-km cycling time-trial power output (watts) before and after IMT. |
| Constant Load 1 and 2 Speed | 8 weeks | More specifically, differences in constant load performance (i.e., speed) before and after IMT. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Perception of Breathing Intensity, Unpleasantness, and Leg Fatigue During Constant Load 1 | 8 weeks | More specifically, whether IMT affects an individual's perception of exertional dyspnea (revised Borg Scales from 0-10 to rate breathing intensity and unpleasantness) and revised Borg Scales from 0-10 to rate leg fatigue during constant load 1 (CL1) cycling. Scores will be reported as whole numbers between 0-10. Higher scores indicate extreme intensity, unpleasantness, or fatigue. |
| Perception of Breathing Intensity, Unpleasantness, and Leg Fatigue During Constant Load 2 | 8 weeks | More specifically, whether IMT affects an individual's perception of exertional dyspnea (revised Borg Scales from 0-10 to rate breathing intensity and unpleasantness) and revised Borg Scales from 0-10 to rate leg fatigue during constant load 2 (CL2) cycling. Scores will be reported as whole numbers between 0-10. Higher scores indicate extreme intensity, unpleasantness, or fatigue. |
| Perception of Breathing Intensity, Unpleasantness, and Leg Fatigue During Time-Trial Cycling | 8 weeks | More specifically, whether IMT affects an individual's perception of exertional dyspnea (revised Borg Scales from 0-10 to rate breathing intensity and unpleasantness) and revised Borg Scales from 0-10 to rate leg fatigue during a 16-km cycling time-trial. Scores will be reported as whole numbers between 0-10. Higher scores indicate extreme intensity, unpleasantness, or fatigue. |
| Deoxygenation of the Respiratory and Limb Locomotor Muscles During Constant Load 1 | 8 weeks | More specifically, the effects of IMT on the deoxygenation (HHb) of the respiratory (RM) and limb locomotor muscles (LM) during constant load 1 (CL1) cycling |
| Deoxygenation of the Respiratory and Limb Locomotor Muscles During Constant Load 2 | 8 weeks | More specifically, the effects of IMT on the deoxygenation of the respiratory and limb locomotor muscles during constant load 2 (CL2) cycling |
| Deoxygenation of the Respiratory and Limb Locomotor Muscles During Time-Trial Cycling | 8 weeks | More specifically, the effects of IMT on the deoxygenation of the respiratory and limb locomotor muscles during a 16-km cycling time-trial |
| Femoral Blood Flow of the Limb Locomotor Muscles During Constant Load 1 | 8 weeks | More specifically, the effects of IMT on femoral blood flow (FBF) of the limb locomotor muscles during constant load 1 (CL1) cycling |
| Femoral Blood Flow of the Limb Locomotor Muscles During Constant Load 2 | 8 weeks | More specifically, the effects of IMT on femoral blood flow (FBF) of the limb locomotor muscles during constant load 2 (CL2) cycling |
Countries
United States
Contacts
PRINCIPAL_INVESTIGATORTim Mickleborough, Ph.D.
Indiana University
Participant flow
Recruitment details
Participants were recruited via flyers posted in the School of Public Health and distributed in Kinesiology labs (e.g., SPH-K409, SPH-K535) and other departmental courses. Flyers were also shared on the IU Classifieds website to reach the broader IU community. 15 participants enrolled; 11 completed the study. 4 withdrew or were excluded (EIB criteria not met or training noncompliance). Recruitment occurred from April 2022 to April 2025 at the School of Public Health.
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Customized Age | 21.1 Years STANDARD_DEVIATION 2.4 |
| Constant Load 1 Speed | 30.73 kilometers per hour (kph) STANDARD_DEVIATION 5.72 |
| Constant Load 2 Speed | 22.94 kilometers per hour (kph) STANDARD_DEVIATION 7.91 |
| EIB Severity | 21.20 Percentage (%) STANDARD_DEVIATION 11.59 |
| MIP | 94.8 centimeters of water (cmH2O) STANDARD_DEVIATION 12.7 |
| Race and Ethnicity Not Collected | 0 Participants |
| Sex: Female, Male Female | 0 Participants |
| Sex: Female, Male Male | 10 Participants |
| SMIP | 781.6 pressure time units (ptu) STANDARD_DEVIATION 336.3 |
| Time-Trial Power | 195.7 Watts (W) STANDARD_DEVIATION 61 |
| Time-Trial Time | 1813.7 seconds (sec) STANDARD_DEVIATION 274.9 |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 10 | 0 / 5 |
| other Total, other adverse events | 0 / 10 | 0 / 5 |
| serious Total, serious adverse events | 0 / 10 | 0 / 5 |
Outcome results
None listed