Inclusion Criteria:  histologically confirmed diagnosis of either primary or secondary GBM received any dose of DEX Karnofsky Performance Status (KPS) >70 English fluency physician approval willingness to travel to Halifax to participate.  Exclusion Criteria:  unstable or symptomatic cardiac or pulmonary disease, injury or co-morbid disease that precludes ability to safely exercise significant cognitive limitations uncontrolled seizures associated with impaired awareness