Normalization of Cardiovascular Fitness in Cancer Survivors Following an Exercise Intervention

Abstract

Research has consistently shown that exercise improves cardiovascular function in cancer survivors. However, this improvement has yet to be compared against the general population. PURPOSE: To evaluate cardiovascular fitness pre and post exercise intervention in cancer survivors against the normative data for a cancer population and the general US population. A secondary purpose was to compare the percent change in cardiovascular fitness in cancer survivors to that of an apparently healthy population. METHODS: Exercise treadmill test performance was evaluated in a cancer population of 543 subjects. Subjects ranged in age from 19 to 70+ years with 79% representing females. Normal distributions for VO2 peak and treadmill time (Bruce protocol) were created for the cancer population at baseline (intake) and following a 3 or 6-month exercise intervention. Cardiovascular values for ten age and gender groups were compared against the normative classifications of a cancer population and the general US population according to ACSM norms. RESULTS: Four age groups improved in cardiovascular classification (from very poor to poor) when evaluated with the US population norms. All but one age group improved its cardiovascular classification (5 groups: average to above average; 3 groups: average to excellent; 1 group: above average to excellent) when evaluated with cancer population norms. Average VO2 peak values improved from 21.6 ± 6.3 mL·kg-1·min-1 to 24.84 ± 6.18 mL·kg-1·min-1. This 15% improvement mirrored the increase in aerobic capacity seen in healthy individuals following a similar exercise intervention. Mean treadmill time improved from 5:52 ± 2:38 minutes to 7:09 ± 2:22 minutes. Prior to the exercise intervention, distinctive peaks in the treadmill time distribution occurred at stage changes at 3:00 and 6:00 minutes. The 3:00 minute peak was not present following the intervention, while 6:00 and 9:00 minute peaks were observed. CONCLUSION: Although all age groups remained in a "very poor or poor" classification based upon US norms, when evaluated using cancer specific norms the data indicated substantial improvement. These improvements parallel the response seen in healthy individuals. This emphasizes the importance of cancer specific normative data.