Inclusion Criteria  Age ≥60 years Have a new diagnosis of AML, MDS, MM, and DLBCL Have a plan to receive outpatient chemotherapy for at least 4 months (patients may enroll within the first 2 weeks of chemotherapy initiation if they do not have grade 2 or higher non-hematologic adverse event) No plan to or unlikely to proceed with autologous or allogeneic hematopoietic stem cell transplantation (SCT) in the following 5 months (if SCT is planned after 4 cycles of chemotherapy in the case of MDS or myeloma, patients are allowed to enroll) English speaking Eastern Cooperative Oncology Group (ECOG) performance status of 0-3 No medical contraindications for exercise per oncologist Able to walk 4 meters as part of Short Physical Performance Battery measured walk (with or without the assistive device) Able to provide informed consent  Exclusion Criteria:  • None