Parent/legal guardian available for consent (if applicable), and patient available for assent and consent
History of anthracycline exposure +/- radiation
Currently in remission, with at least 6 months off chemotherapy
Able to perform CPET
Baseline CPET with VO2 \<80% (at start of study, or CPET at CHLA after January 2020)
Smartphone compatible with Fitbit (own or parent/legal guardian's)
Ability to complete and send diary and Fitbit information on a weekly basis
Ability to participate in monthly virtual check-in visits
Baseline activity prior to intervention \<30min/day, 2x/week
You may not be if
Inability to obtain consent/assent
Unable to accurately perform quality of life survey independently
No other primary medical diagnosis (e.g., Down Syndrome, Wolff-Parkinson-White Syndrome, congenital heart disease) or history of cardiothoracic surgery
Contraindication to moderate activity (\>3 METs). Examples include history of malignant arrhythmias, exercise-induced syncope, severe symptoms of HF (NYHA IV, ACC/AHA Stage D)
Unable to perform CPET, echocardiogram, EKG, or obtain laboratory studies
Unable to perform mild activity for at least 0.5h/day and at least 2x/week
Unable to come to hospital for study visits at 0 and 6 months
Unable to complete study-related surveys
Unable to complete and send diary and Fitbit information on a weekly basis
