Inclusion criteria:
Informed Consent for Study Participation
Patients with breast cancer over 50 years old who require adjuvant or neoadjuvant chemotherapy.
Patients with a functional level of 0 or 1 based on the Eastern Cooperative Oncology Performance Status (ECOG PS) questionnaire.
Exclusion criteria:
Patients with known underlying conditions including uncontrolled diabetes, uncontrolled high blood pressure, cardiovascular diseases and heart failure, chronic kidney disease, chronic liver disease, autoimmune disease, obstructive respiratory disease, uncontrolled thyroid disorder, history of stroke, seizures, and mental disorder requiring medication.
Use of sleep aids or fatigue-reducing medications prior to the start of the intervention.
Unwillingness to continue cooperation in the study.
Lifestyle that interferes with the nocturnal sleep rhythm (e.g., those who work night shifts).
Previous history of chemotherapy.
Diagnosis of metastasis.
Development of severe toxicities that could not be controlled with standard doses, such as nausea.