Objective: To evaluate the effects of a six-month intradialytic aerobic exercise program on left ventricular ejection fraction in patients with end-stage kidney disease undergoing maintenance hemodialysis.

Materials and Methods Design: Open-label, single-center, quasi-experimental, single-group study with pre- and post-intervention measurements.

Study setting: the outpatient hemodialysis unit of the National Institute of Medical Sciences and Nutrition Salvador Zubirán.

Participants: Patients aged ≥18 years with chronic kidney disease on hemodialysis for at least three months, who are at their dry weight.

Procedures: An echocardiogram will be performed post-hemodialysis. Subsequently, patients will undergo a 30-minute intradialytic aerobic exercise program at submaximal intensity during the second hour of dialysis, three times per week for six months. At the end of the six-month period, a post-hemodialysis echocardiogram will be repeated.

Inclusion Criteria:

• Adults aged ≥18 years
• Receiving hemodialysis with a stable prescription for at least 3 months
• At their prescribed dry weight
• Provision of written informed consent

Exclusion Criteria:

• Active cardiovascular disease within the past 3 months
• Left ventricular ejection fraction <40%
• Physical and/or cognitive impairment precluding exercise
• Blood pressure >160/110 mmHg

Individual participant data (IPD) will not be shared in order to protect patient privacy and confidentiality and to comply with institutional and ethical regulations.