Breathlessness Perceptions Within Respiratory Diseases (BiRD)

Inclusion criteria is:

• Aged 18 or over up to 100
• Known respiratory diagnosis* OR Healthy control**
• Ongoing symptoms of breathlessness defined as ≥2 MRC dyspnoea scale
• Able to communicate in English
• Able to attend two study visits

• Able to provide written informed consent

  • Known respiratory diagnosis could include, but is not limited to, Chronic Obstructive Pulmonary Disease, Asthma,Bronchiectasis or Interstitial Lung Disease.

    • Healthy controls are required to have an absence of a functionally limiting condition such as respiratory, cardiovascular, or musculoskeletal.

Participants are excluded if,:

• Unstable disease or undergoing investigations for unexplained symptoms
• Undergone a surgery within past six weeks
• Contraindications for exercise outlined by American College of Sports Medicine guidelines (Unstable Cardiovascular disease, hypertension etc)
• Body Mass Index ≥ 35kg/m2
• Unable to communicate in English
• Unable to provide consent

Peak Oxygen Uptake (VO2 peak) meausured through mL/min or L/min, If >=85 is normal, 65-84 is mildly reduced, 50-64 is moderately reduced and <50 is severely reduced.

Carbon Dioxide Output (VCO2) and RER (VCO2/VO2) meausured through mL/min or L/min, VCO2 roughly rises parallel to VO2. The volume of CO₂ produced per minute by the body reflects the metabolic CO₂ production from aerobic and anaerobic metabolism combined. The respiratory exchange ratio which is RER gives a clear indication whether the test was maximal effort or not.

RER >=1.10 is the key cutoff.

AT will all be meausured through mL/min or L/min. Normal: typically > 40% of predicted VO₂ max, or ≥ 11 ml/kg/min Higher AT = better - indicates the body can sustain aerobic metabolism at higher workloads before switching to anaerobic system.

This is measured by breaths per minute. The amount of breaths taken will indicate how your brain and lungs are functioning to clear the carbondioxide which will help to maintain the chemical balance.

Resting phase 12 to 20 breaths/min -Baseline range Peak Exercise 35 to 45 breaths/min -Normal physiological range for healthy adults.

This will be measured by mmHg Before the test (At rest) >=200/110- Contraindication not to perform the exercise test <90/60- Too low for the baseline

During the exercise test, If the systolic value exceeds 190 or 210 indicates a severe hypertension A critical stop would be a systolic value exceeding 250 or a diastolic value exceeding 115.

After the test, The blood pressure should return to near or actual borderline taken during rest.

LF-Low Frequency Power and HF-High Frequency Power are both measured by milliseconds squared or absolute units.

LF Absolute 300 to 1500- considered good LF Absolute <100 -considered bad/abnormal

HF Absolute 200 to 1000- considered good HF Absolute <50- considered bad/abnormal

LF/HF ratio will be a dimensionless ratio represented without any units. High rates will suggest of sympathetic predominance.

At rest Good range will be 1.0-2.0 Bad range >5 or <0.5