Moderate-to-vigorous Physical Activity May Offset Harms Of Sedentary Time On An Older Adult’s Functional Fitness

Abstract

The ability to maintain functional fitness is important for preserving quality of life and promoting a healthy aging process. Habitual physical activity, especially that of moderate-to-vigorous intensity, has been associated with improvements in functional fitness resulting in enhanced functioning and reduced risk of disability, morbidity and mortality of older adults, whereas high amounts of sedentary time (ST) have been inversely associated with functional fitness and related with detrimental effects on several health-related outcomes. PURPOSE: We aimed to assess if moderate-to-vigorous physical activity (MVPA) can moderate the relationship between ST and functional fitness and, thus, offset the adverse effects of ST in older adults. METHODS: Older adults (≥65 years old) from the national surveillance system in Portugal (n = 564) had their MVPA and ST assessed using accelerometers. Functional fitness was assessed using the Senior Fitness Test battery and an overall z-score based on the individual scores for each fitness item was created. Multiple linear regression was used to model the outcomes, while adjusting for age, sex, BMI, and accelerometer wear-time. RESULTS: Higher ST was related with lower functional fitness (β = -0.01, p < 0.0001), whereas increases in MVPA were related to a higher fitness level (β = 0.02, p = 0.001). There was a moderating effect of MVPA on the relationship of ST with functional fitness (p < 0.0001), where MVPA ≥34.66 min/d ameliorated the significant inverse relationship between ST and functional fitness, whereas, engaging in ≥68.60 min/d of MVPA resulted in ST having a significant positive relationship with functional fitness. CONCLUSION: MVPA was found to be a moderator of the relationship between ST and functional fitness in older adults, such that engaging in at least 35 min/day of MVPA may offset the negative associations related with ST. Moreover, with higher levels of MVPA (≥69 min/d), having some ST may provide some benefit to an older adult’s ability to maintain functional fitness. This investigation was funded by the Portuguese Foundation for Science and Technology (UIDB/00447/2020). IRC is supported by the Portuguese Foundation for Science and Technology (IRC: SFRH/BD/149394/2019).