High-Flow Nasal Cannula on Exercise Tolerance in Heart Failure Patients Undergoing Cardiac Rehabilitation.

Brief Summary

The goal of this clinical trial is to learn if a high-flow nasal cannula (HFNC) - a device that delivers warm, humidified air through a small tube placed in the nostrils - can improve exercise tolerance in adults with heart failure who are entering a cardiac rehabilitation program. The main questions it aims to answer are: * Can HFNC help people with heart failure exercise for a longer time during a treadmill test? * Does HFNC lower how hard people feel they are working during exercise? Researchers will compare exercise performance with HFNC to exercise performance without HFNC to see if HFNC helps people with heart failure tolerate exercise better. Participants will: * Complete two treadmill exercise tests, one with HFNC and one without, in a randomly assigned order * Wait 48 to 72 hours between the two tests to allow full recovery * Have their heart rate, blood pressure, oxygen level, and breathing rate measured before and after each test