Effects of Light and Moderate-to-Vigorous Physical Activity on Fatigue and Health-Related QoL in Breast Cancer

By Dustin Samples - February 8, 2023

In a study published in Supportive Care in Cancer, a team of researchers from Sweden and Norway looked at the benefits of substituting either light physical activity (LPA) or moderate-to-vigorous physical activity for sedentary time in patients with breast cancer. The study’s goals were to determine 1) whether this substitution would improve cancer-related fatigue and health-related quality of life (HRQoL) and 2) what amount of LPA or MVPA in minutes per day is required to significantly improve these areas.

Using the Multidimensional Fatigue Inventory (MFI) and European Organisation for Research and Treatment of Cancer quality of life questionnaires, the researchers determined baseline fatigue and HRQoL, respectively, in 436 participants. They measured sedentary time and physical activity in the participants with accelerometry.

The Researchers reported “Fatigue significantly decreased in two MFI dimensions when reallocating 30 min/day of sedentary time to LPA: reduced motivation and reduced activity (β =  − 0.21). Fatigue significantly decreased in three MFI dimensions when reallocating 30 min/day of sedentary time to MVPA: general fatigue (β =  − 0.34), physical fatigue (β =  − 0.47) and reduced activity (β =  − 0.48).”

The amount of time needed to produce a minimal clinically significant change in MFI was a staggering 290 min/day of LPA or ≥125 min/day of MVPA. Further, there were no clinically significant effects of either LPA or MVPA on HRQoL.

“Our results suggest that reallocating sedentary time to LPA or MVPA has beneficial effects on cancer-related fatigue in patients with breast cancer, with MVPA having the greatest impact. However, a large amount of time reallocation is needed to produce clinically important changes in relatively healthy (e.g. low levels of fatigue) and physically active breast cancer populations,” the team concluded.


Reallocating sedentary time to physical activity: effects on fatigue and quality of life in patients with breast cancer in the Phys-Can project