Dose-response relationship between exercise and cognitive function in older adults with and without cognitive impairment: A systematic review and meta-analysis

Abstract

This systematic review and meta-analysis examined the dose-response relationship between exercise and cognitive function in older adults with and without cognitive impairments. We included single-modality randomized controlled aerobic, anaerobic, multicomponent or psychomotor exercise trials that quantified training frequency, session and program duration and specified intensity quantitatively or qualitatively. We defined total exercise duration in minutes as the product of program duration, session duration, and frequency. For each study, we grouped test-specific Hedges’ d (n = 163) and Cohen’s d (n = 23) effect sizes in the domains Global cognition, Executive function and Memory. We used multilevel mixed-effects models to investigate dose-related predictors of exercise effects. In healthy older adults (n = 23 studies), there was a small positive effect of exercise on executive function (d = 0.27) and memory (d = 0.24), but dose-parameters did not predict the magnitude of effect sizes. In older adults with cognitive impairments (n = 13 studies), exercise had a moderate positive effect on global cognition (d = 0.37). For older adults with cognitive impairments, we found evidence for exercise programs with a short session duration and high frequency to predict higher effect sizes (d = 0.43–0.50). In healthy older adults, dose-parameters did not predict the magnitude of exercise effects on cognition. For older adults with cognitive impairments, exercise programs with shorter session duration and higher frequency may generate the best cognitive results. Studies are needed in which different exercise doses are directly compared among randomized subjects or conditions.

Effects of low- and high-intensity physical exercise on physical and cognitive function in older persons with dementia: a randomized controlled trial

“…Unfortunately, a previous systematic review on the effects of exercise on physical function in PwD could not yet determine the characteristics of successful interventions [45]. Although a larger training volume in general was related to more improvements in physical function, there is currently not enough evidence to determine how program duration, session duration, frequency, and intensity each contribute to exercise effects on functional outcomes in PwD [5]. Partly, this results from a scarcity of studies that report dose parameters subjectively and/or objectively [5], and a shortage of studies in PwD in which the effects of different exercise doses are compared among randomized subjects or conditions [5], further illustrating the need for the current study.…”

“…Although a larger training volume in general was related to more improvements in physical function, there is currently not enough evidence to determine how program duration, session duration, frequency, and intensity each contribute to exercise effects on functional outcomes in PwD [5]. Partly, this results from a scarcity of studies that report dose parameters subjectively and/or objectively [5], and a shortage of studies in PwD in which the effects of different exercise doses are compared among randomized subjects or conditions [5], further illustrating the need for the current study. Last, the generally low number of participants (mean N = 56) across the aforementioned exercise studies [11,45,70,71] may complicate the interpretation of exercise effects on physical function in PwD.…”

“…In healthy older adults, both aerobic and strength exercises are associated with improvements in cognitive functions such as executive function, inhibitory control and episodic memory [3][4][5], and physical functions, i.e., muscle strength, balance, functional reach, mobility, and endurance [4,[6][7][8][9]. Regrettably, the effects of exercise on these cognitive and physical functions in PwD have been inconsistent [5,[10][11][12][13][14]. In PwD, combined aerobic and strength exercise appears to be more effective for cognitive and physical benefits than aerobic training only [11].…”

“…Furthermore, exercising at moderate-to-vigorous intensities is recommended over lighter intensities for cardiovascular, muscular, and neuromotor benefits in healthy young and old adults [41]. Whether this is true also for cognitive functions is undetermined [5].…”

Physical Exercise Interventions Targeting Cognitive Functioning and the Cognitive Domains in Nondementia Samples: A Systematic Review of Meta-Analyses

“…The Angevaren et al's15 comparison of aerobic exercise versus no intervention was however nonsignificant, and there were no further significant comparisons in other meta-analyses 9,20. Sanders et al18 reported a significant effect of physical exercise interventions versus any control for memory (g ¼ 0.31, P < .05) in disease-free adults. Scherder et al 22 reported a beneficial effect of walking versus control on executive function in disease-free adults (g ¼ 0.36, P < .01) in a meta-analysis including 5 RCTs (N ¼ 363) without significant heterogeneity.…”