The Impact of Varying Exercise Training Intensity on Clinical Asthma Outcomes and Inflammation in Adults with Asthma

Screening Visit: Participants will be screened for study eligibility. This visit will include medical history, medication usage, height, weight, lung function, asthma control, exhaled nitric oxide (eNO), blood pressure and the ESSA pre-exercise screening questionnaire. This visit should take less than one hour to complete. Once eligibility has been confirmed, participants will be provided with an accelerometer to wear for 7 days and a semi-quantitative food diary to complete for four days prior to Visit 1. Visit 1a: Participants will be instructed to abstain from moderate- and vigorous-intensity exercise for the two days prior, and all activity for 12 hours prior to Visit 1. Participants will be instructed to withhold their asthma medications for 6-24 hours and anti-histamine medications for 5 days. Participants will need to fast for at least 12 hours prior to their visit. On arrival to the clinic participants will have their accelerometer and food diary collected, their weight checked and a venous blood sample collected. Fractional exhaled nitric oxide (FeNO) will be measured and spirometry performed. Sputum induction coupled with bronchial provocation will be performed over a standardised 15.5 minutes nebuliser time using 4.5% hypertonic saline. Body composition and bone density will be measured by dual-energy x-ray absorptiometry (DXA). Skin allergy testing will be completed for a panel of common environmental allergens (dust mite, grass, cockroach, moulds) and asthma, exercise and dietary questionnaires will be completed. This visit should take approximately 2.5 hours to complete and will be conducted by a research assistant or postdoctoral research fellow with experience in performing these procedures. Visit 1b: At a separate appointment, VO2max testing will be conducted at The University of Newcastle campus by an exercise physiology intern with training in conducting VO2max measurements. Participants will perform a progressive exercise test on a treadmill. The test commences at an easy workload and becomes progressively harder each minute until the participant voluntarily ends the test or they reach pre-determined end criteria (e.g. HR target; R>1.15). Throughout the test, heart rate, oxygen consumption and ventilation are monitored continuously. In order to measure oxygen consumption and ventilation, participants wear a face mask and their expired air is sampled for analysis. The face mask allows participants to speak clearly so communication throughout the test is maintained. Participants can end the test at any stage. Following VO2max testing, participants randomisation will be revealed. Participants will be randomised to complete either: a) Three months of moderate-intensity exercise training, including at least 3 one hour exercise sessions/week involving activities that maintain heart rate between 55-70% HRmax; or b) Three months of vigorous-intensity exercise training, including at least 3 one hour exercise sessions/week involving activities that maintain heart rate between 70-85% HRmax; or c) Three months of the control condition (no intervention). Visits 2a and 2b: Participants will return to the clinic following the three month intervention, to repeat all procedures completed during Visit 1a and 1b. Prior to these visits, participants will be instructed to wear an accelerometer for one week and complete a 4-day semi-quantitative food diary. Participant Weekly Questionnaires Participants will complete the ACQ6 and quantify their physical activity participation for the preceding week in an online questionnaire to be completed each week. This will assist with monitoring adherence to the intervention protocols. Exercise Protocol Participants will undertake three months of exercise training at The University of Newcastle campus. Participants will be required to complete three x 1 hour exercise sessions per week, with all sessions to be supervised to encourage attendance and compliance with maintaining the appropriate heart rate for each session. These one-on-one sessions will be supervised by exercise physiology intern students. Heart rate will be monitored and recorded throughout the entire session. Moderate-intensity exercise training sessions will be completed at 55-70% of HRmax, while vigorous-intensity exercise will be completed at 70-85% of HRmax. Exercise will be personalised to the patients preference of equipment using a combination of treadmills, cycle ergometers and elliptical ergometers. Participants randomised to the control intervention will be offered a pedometer to keep at the conclusion of the study.