A Study Investigating the Impact of IMT With CR On Exercise Responses In HF

This study is testing whether a breathing muscle training technique called Inspiratory Muscle Training (IMT) combined with controlled carbon dioxide rebreathing can improve exercise tolerance and reduce breathlessness in patients with heart failure with reduced ejection fraction (HFrEF) — a type of heart failure where the heart does not pump enough blood. **You may be eligible if...** - You are 18 or older - You have been diagnosed with HFrEF and are on stable heart medication for at least 6 weeks - Your heart failure symptoms are mild to moderate (NYHA Class I to III) - You have not been hospitalized in the last 3 months - Your BMI is 45 or below and you are a non-smoker with fewer than 30 pack-years of smoking history - You are physically able to exercise without major orthopedic limitations **You may NOT be eligible if...** - You have had dangerous heart rhythm problems within the last 21 days - You have a second or third-degree heart block - You are a current smoker or have a heavy smoking history - Your BMI is above 45 Talk to your doctor to see if this trial is right for you.