Could a simple drink help people with heart failure breathe and move easier?

This study is testing whether drinking a ketone supplement for eight weeks can help people with a common type of heart failure (HFpEF) exercise more easily and improve their heart function. It involves about 20 participants who will try both the ketone drink and a placebo drink at different times to compare the effects. The main goal is to see if the drink increases the amount of oxygen the body can use during peak exercise, which is a key measure of fitness and symptom burden in this condition.