Activity Tracker to Prescribe Various Exercise Intensities in Breast Cancer Survivors

Activity Tracker to Prescribe Various Exercise Intensities in Breast Cancer Survivors: Purpose

To prescribe different physical activity (PA) intensities using activity trackers to increase PA, reduce sedentary time and improve health outcomes among breast cancer survivors. The maintenance effect of the interventions on study outcomes was also assessed.

Methods

The Breast Cancer and Physical Activity Level (BC-PAL) pilot trial randomized 45 breast cancer survivors to a home-based, 12-week lower (300 minutes/week at 40-59% of heart rate reserve) or higher (150 minutes/week at 60-80% of heart rate reserve) intensity PA, or no PA intervention/control. Both intervention groups received Polar A360® activity trackers. Study outcomes assessed at baseline, 12- and 24-weeks included PA and sedentary time (ActiGraph GT3X+), health-related fitness (e.g. body composition, cardiopulmonary fitness/VO2max) and patient-reported outcomes (e.g. quality of life). Intention-to-treat analyses were conducted using linear mixed models and adjusted for baseline outcomes.

Results

Increases in moderate-vigorous intensity PA (least squares adjusted group difference (LSAGD)= 0.6 (95% confidence interval (CI)= 0.1, 1.0)) and decreases in sedentary time (LSAGD= -1.2 (95% CI= -2.2, -0.2)) were significantly greater in the lower intensity PA group versus control at 12-weeks. Increases in VO2max at 12-weeks in both interventions groups were significantly greater than changes in the control group (lower intensity PA group LSAGD= 4.2 (95% CI= 0.5, 8.0 ml/kg/min); higher intensity PA group LSAGD= 5.4 (95% CI= 1.7, 9.1 ml/kg/min)). Changes in PA and VO2max remained at 24-weeks, but differences between the intervention and control groups were no longer statistically significant.

Conclusion

Increases in PA time and cardiopulmonary fitness/VO2max can be achieved with both lower- and higher-intensity PA interventions in breast cancer survivors. Reductions in sedentary time were also noted in the lower intensity PA group.

Send correspondence and reprint requests to: Jessica McNeil, Ph.D., Department of Cancer Epidemiology and Prevention Research, CancerControl Alberta, Alberta Health Services, Holy Cross Centre, Room 508B, Box ACB, 2210 2nd street SW, Calgary, Alberta, Canada, T2S 3C3, Phone: 1-403-698-8163, Fax: 1-403-264-2654, E-mail: Jessica.McNeil2@albertahealthservices.ca

Dr. McNeil is a recipient of Postdoctoral Fellowship Awards from the Canadian Institutes of Health Research and Alberta Innovates-Health Solutions. Dr. Brenner was supported by a Capacity Development Award in Cancer Prevention from the Canadian Cancer Society (#703917). Ms. Stone was supported by the Queen Elizabeth II (Province of Alberta) Scholarship. Dr. Vallance holds a Tier II Canada Research Chair. Dr. Courneya holds a Tier I Canada Research Chair. Dr. Friedenreich was supported by a Health Senior Scholar Award from Alberta Innovates-Health Solutions and the Alberta Cancer Foundation Weekend to End Women’s Cancers Breast Cancer Chair. The results of this study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. The results of the present study do not constitute endorsement by ACSM.

CONFLICTS OF INTEREST AND SOURCES OF FUNDING: The authors declare no conflicts of interest. Pilot data collection for the BC-PAL Trial was funded by a Catalyst Grant from the O’Brien Institute for Public Health, University of Calgary and the Carole May Yates Memorial Endowment for Cancer Research Fund, administered through the Arnie Charbonneau Cancer Institute, University of Calgary.

Accepted for Publication: 2 January 2019

© 2019 American College of Sports Medicine