Physical activity moderates the effect of sedentary time on an older adult's physical independence

Abstract

Background/objectives Moderate‐to‐vigorous physical activity (MVPA) and breaks in sedentary time (BST) have been proposed as viable solutions to improve an older adult's physical independence, whereas sedentary time (ST) has been associated with detrimental effects. We sought to assess the joint effects of ST, BST, and MVPA on the physical independence of older adults and determine whether and to what extent the ST relationship with physical independence is moderated by MVPA and/or BST. Design Cross‐sectional. Setting Laboratory of Exercise and Health, Faculty of Human Kinetics. Participants Older adults (≥65 years old) from the national surveillance system in Portugal (n = 821). Measurements Physical activity and ST were assessed by accelerometry. Physical independence was assessed using a 12‐item composite physical function (CPF) questionnaire. Multiple linear regression was used to model the outcomes. Results Higher ST was related to lower CPF score (β = −0.01, p < 0.0001), whereas higher MVPA was related to better CPF score (β = 0.02, p < 0.0001). BST was not related to physical independence after accounting for MVPA and ST (β = 0.03, p = 0.074). MVPA had a moderating effect on the relationship of ST with CPF score (p < 0.0001), where MVPA ≥36.30 min/day ameliorated the significant inverse relationship between ST and CPF. Engaging in ≥107.78 of MVPA resulted in ST having a significant positive relationship with CPF score. No moderation effect was found for BST (p > 0.05). Conclusion Regardless of the time spent in MVPA and BST, ST was inversely related to CPF. However, MVPA was found to be a moderator of the relationship between ST and physical independence, such that engaging in at least 36 min/day of MVPA may blunt the negative effects of ST. At high levels of MVPA (≥108 min/day), having some ST may actually provide some benefit to an older adult's ability to maintain physical independence.

Diurnal pattern of breaks in sedentary time and the physical function of older adults

“…A possible explanation is that a stronger stimulus than a muscular contraction originates from a break in sedentary time may be needed to induce an improvement in physical function outcomes, such as handgrip strength and lower limb strength [ 32 ]. Furthermore, a previous study also indicated that a break in sedentary time was not related to subjective physical function, taking into account MVPA and the duration of the sedentary period [ 33 ]. Another possible explanation for the non-significant associations found in our study could be that the participants’ characteristics [ 30 , 31 ].…”

Relative Sit-to-Stand Muscle Power Predicts an Older Adult’s Physical Independence at Age of 90 Yrs Beyond That of Relative Handgrip Strength, Physical Activity, and Sedentary Time

“…28 A limitation to this investigation is its cross-sectional design, which does not allow for the establishment of causality, nor the exclusion of reverse causality in the relationships between STS relative muscle power and projected physical independence. Moreover, although the CPF scale has been validated 13 and used in previous studies to assess physical independence of older adults, 10,11,29,30 it is based off of self-report, which could have biased results. Having a longitudinal approach would allow for a more precise determination of the minimum relative STS power levels necessary to maintain physical independence in old age.…”

“…sedentary time (ST), which have previously been shown to be strong predictors of an older adult's physical independence, 10,11 remains to be analyzed. This investigation aimed to assess the predictive ability of STS relative muscle power to determine an older adult's projected physical independence at age of 90 yrs beyond that of relative handgrip strength, PA, and ST.…”

“…Despite the recognized importance of muscle power, the measurement of muscle strength via handgrip continues to be the most widely used method to assess muscle function and physical dependence 8,9 . Whether relative STS muscle power is a better predictor of an older adult’s projected physical independence at age of 90 yrs, compared with handgrip strength as well as to objectively measured physical activity (PA) and sedentary time (ST), which have previously been shown to be strong predictors of an older adult’s physical independence, 10,11 remains to be analyzed.…”

Implantação Da Caderneta De Saúde Da Pessoa Idosa Em Uma Estratégia Saúde Da Família (Esf) Do Leste De Minas

“…Porém estudos apontam vários fatores podem influenciar negativa ou positivamente a participação dos idosos em atividades físicas tais como socioeconómicos, ambientais e de saúde (PINTO, 2018). As principais barreiras referidas foram a limitação física, e os facilitadores o apoio formal (HETHERINGTON-RAUTH et al, 2021;JORDÃO et al, 2023;PINTO, 2018;SANTOS et al, 2012). Equipamentos como pedómetros e acelerómetros têm sido amplamente aplicados na avaliação dos padrões de atividade física em idosos.…”