Clinical trial NCT06336681: Inspiratory Muscle Training on The Severity of Exercise-Induced Bronchoconstriction and Time-Trial Performance (IMT_EIB)
Official title: Effect of Flow-Resistive Inspiratory Muscle Training on The Severity of Exercise-Induced Bronchoconstriction and Cycling Time-Trial Performance
Study type: INTERVENTIONAL
Overall status: RECRUITING
Phase: NA
Conditions: Exercise Induced Bronchospasm
Exercise Induced Asthma
Lead sponsor: Indiana University
Sponsor class: OTHER
First posted: 2024-03-29
Enrollment: 20
Sex: ALL
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

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.

Eligibility criteria: 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

Primary outcomes:
measure: Exercise-Induced Bronchoconstriction (EIB) Severity
timeFrame: 8 weeks
measure: Maximum Inspiratory Pressure and Sustained Maximum Inspiratory Pressure
timeFrame: 8 weeks
measure: 16-km Cycling Time-Trial Time to Completion
timeFrame: 8 weeks
measure: 16-km Cycling Time-Trial Power Output
timeFrame: 8 weeks
measure: Constant Load Performance
timeFrame: 8 weeks
Secondary outcomes:
measure: Perception of Breathing Intensity and Unpleasantness and Leg Fatigue
timeFrame: 8 weeks
measure: Deoxygenation of the respiratory and limb locomotor muscles by near-infrared spectroscopy
timeFrame: 8 weeks
measure: Femoral blood flow (FBF) of the limb locomotor muscles by ultrasound
timeFrame: 8 weeks
measure: Lung Volumes
timeFrame: 8 weeks
Other outcomes:
Locations:
city: Bloomington
country: United States
facility: School of Public Health-Bloomington
state: Indiana
Study officials:
affiliation: Indiana University
name: Tim Mickleborough, Ph.D.
role: PRINCIPAL_INVESTIGATOR
References: