Association between continuous device-based physical activity monitoring over six months and cardiorespiratory, metabolic and body composition outcomes in post-surgery cancer survivors - An observational cohort analysis within a randomized controlled trial (CRBP-TS Study).

Background: The current guidelines for physical activity often rely on self-reported data or short-term activity tracking. We aimed to explore device-based long-term physical activity tracking and its possible association with cancer survivors' cardiorespiratory fitness (CRF), metabolic health, and body composition.

Methods: In this observational analysis of a randomized controlled trial (CRBP-TS study), we reanalyzed data from 111 patients with breast, prostate, and colorectal cancer. Dependent variables included cardiorespiratory outcomes, body composition, metabolic biomarkers, and fatigue. A multiple linear regression model was used to analyze the data, considering age, gender, BMI, and baseline values. A consumer wearable device measured moderate-to-vigorous physical activity (MVPA) and steps continuously over six months, ensuring a detailed and accurate record of the participants' daily physical activity.

Results: Physical activity data from all participants indicated a mean of moderate physical activity 108 min/wk (SD ± 88), vigorous physical activity 41 min/wk (SD ± 36), and 8498 steps/day (SD ± 2490). We observed that higher levels of MVPA were significantly associated with higher maximum oxygen uptake (VO_2max; β = 0.5, 95% CI [0.02 to 1.0], p = 0.042), higher peak power output (PPO; β = 0.04, 95% CI [0.003 to 0.08], p = 0.037), and higher cardiac output (β = 0.6, 95% CI [0.2 to 1.1], p = 0.009). Additionally, more steps correlated significantly with higher VO_2max (β = 0.27, 95% CI [0.04 to 0.51], p = 0.023), higher cardiac output (β = 0.2, 95% CI [0.013 to 0.47], p = 0.039), lower fat mass (β= -0.24, 95% CI [-0.44 to 0.03], p = 0.028), lower insulin (β=-4.2, 95% CI [-6.4 to -2.0], p < 0.000), and lower leptin (β=-0.56, 95% CI [-0.97 to -0.15], p = 0.008).

Conclusions: Continuous activity tracking with wearable devices provides an objective and standardized opportunity to investigate the amount of aerobic physical activity and its association with systemic health outcomes in cancer survivors. Our long-term activity data support a positive relationship between aerobic physical activity and cardiorespiratory fitness as well as metabolic health.

Trial registration: DRKS-ID: DRKS00020499; Registered 17 March 2020, https://drks.de/search/en/trial/DRKS00020499 .