Cross-Sectional & Longitudinal Associations between Light-Intensity Physical Activity & Physical Function Among Cancer Survivors

Abstract

Purpose: While moderate-vigorous intensity physical activities (MVPA) confer the greatest health benefits, evidence suggests that light-intensity activities are also beneficial, particularly for older adults and individuals with moderate-severe comorbidities. Cross-sectional and longitudinal associations between light-intensity physical activity and physical function were examined in elderly cancer survivors, who are at increased risk for age- and treatment related comorbidities, including accelerated functional decline. Methods: The analysis included 641 breast, prostate, and colorectal cancer survivors (54% female) aged 65 and older who participated in a 1-year, home-based diet and exercise intervention designed to reduce the rate of physical function decline. Pre- and post-intervention physical activity and function were assessed via the CHAMPS questionnaire, the SF-36 physical function subscale (PFS) and the Late Life Function and Disability Index basic and advanced lower-extremity function (LEF) subscales. ANCOVA was used to compare means of physical function across levels of PA intensity (low-light (LLPA): 1.0-2.0 METs; high-light (HLPA): 2.1-2.9 METs; MVPA: ≥3.0 METs). Results: After adjustment for age, sex, BMI, comorbidities, symptoms, and MVPA, increasing tertiles of baseline light-intensity activity were associated with higher scores for all 3 measures of baseline physical function (all p-values <0.005). Associations were stronger for HLPA than for LLPA. Compared with survivors who decreased or remained stable in MVPA and HLPA at the post-intervention follow-up, those who increased in HLPA, but not MVPA, reported higher physical function scores (LSMeans (95% CI): SF-36 PFS: −5.58 (−7.96, −3.20) vs. −2.54 (−5.83, 0.75), p = 0.14; basic LEF: -2.00 (−3.45, −0.55) vs. 0.28 (−1.72, 2.28), p = 0.07; advanced LEF: −2.58 (−4.00, −1.15) vs. 0.44 (-1.52, 2.40), p = 0.01). Conclusions: Our findings suggest that increasing light-intensity activities, especially HLPA, may be a viable approach to reducing the rate of physical function decline in individuals who are unable or reluctant to initiate or maintain adequate levels of moderate-intensity activities.