Is High-Intensity Functional Training Sufficient for Improving Cardiovascular Endurance in Cancer Survivors?

Abstract

PURPOSE: Cancer survivors are recommended to follow the 2008 Physical Activity Guidelines for Americans (PAG), although specific guidelines for appropriate exercises are lacking. High-intensity functional training (HIFT) has been shown to take less time to improve metabolic and physiological adaptations than previously tested measures. This study tested cardiovascular endurance of cancer survivors who participated in HIFT and compared their workouts to the aerobic PAG. METHODS: Cancer survivors with last treatment within 5 years were recruited (n=8; ages 47-60, 25% male). Participants were screened for comorbidity and had approval from their primary care physician. HIFT was conducted 3 d/wk for 5 wks (60-minute sessions: warm-up and cool-down with varied workouts that included aerobic and resistance exercises averaging 12:23); 12 HIFT workouts and 4 testing sessions were completed. A pre and post 6-minute walk test (6MWT) was conducted to measure cardiovascular endurance; participants walked on a 200-meter track for six minutes and the total distance walked was calculated. Participants wore Polar heart rate monitors at all times. Max heart rate was calculated: MaxHR= 207-0.7 x age and exercise intensity was calculated: moderate (50-70% MaxHR), and vigorous (>70% MaxHR). Every minute of vigorous intensity was doubled, added to the measured time spent at moderate activity, and compared to the aerobic PAG (150min of moderate aerobic exercise per week). Two participants dropped out after HIFT workouts 1 and 4; their heart rate data for completed sessions was included. Adherence averaged 10.33±2.25 HIFT workouts; total HR observations=63. RESULTS: The average session lasted 48:48±10:51 (vigorous intensity M=10:57±10:51; moderate intensity M=24:43±12:43). Per week, participants completed a calculated average of 139:51 of moderate intensity aerobic activity. There was a significant improvement in the 6MWT (638.3±41.2m vs 733.8±19.1m, t=3.23, p=0.39) CONCLUSION: Based on HR data, HIFT alone for 3 d/wk did not meet the 2008 aerobic PAG; however, it was sufficient to improve cardiovascular endurance. All participants reached vigorous heart rates with HIFT. It is important to look at indicators of improvement and not only time spent active to determine what exercises are appropriate for cancer survivors.