The Effect of Intradialytic Exercise on Cognition in Renal Patients Undergoing Hemodialysis: An Updated Systematic Review of Randomized Controlled Trials.

Abstract

<b>Background/Objectives</b>: Hemodialysis patients are disproportionately affected by impaired cognitive function in comparison to the general population. This systematic review aims to update and expand the current evidence regarding the effects of IET interventions on global cognition and specific cognitive domains, such as executive function, processing speed, and attention. <b>Methods</b>: A comprehensive search was conducted across three databases (PubMed, Scopus, and EBSCO) from database inception to 24 August 2025 for randomized controlled trials examining the effects of intradialytic exercise training on cognitive function, using combinations of the following search terms: hemodialysis, dialysis, dialy*, physical exercise, physical activity, exercise, activity, activit*, cognition, cognitive, and cognit*. Included studies were assessed for risk of bias and methodological quality using the Jadad Scale and NHLBI tools. <b>Results</b>: Seven studies were included in this review, encompassing (n = 332; 60.4% male) hemodialysis patients aged from 48 to 74.9 years. In comparison to standard care, IET significantly improved global cognition and specific cognitive domains. Regarding global cognitive function, interventions regardless of exercise type, which were performed thrice weekly over 12 to 16 weeks, significantly improved scores in (n = 4; 57%) studies using the Montreal Cognitive Assessment (MoCA) and in (n = 1; 14%) study using the Mini Mental State Examination. Regarding specific cognitive domains, aerobic exercise performed thrice weekly for 12 weeks were associated with statistically significant improvements in the following: executive function scores (n = 2; 29%), studied using the Trail Making Test (TMT) Part-B and TMTB-A; psychomotor processing speed (n = 1; 14%), studied using TMT-A and Symbol Digit Modality Test (SDMT); and alertness (n = 1; 14%), studied using the Test of Attentional Performance (TAP) test. <b>Conclusions</b>: The collective evidence confers that IET is an effective intervention that may moderately improve global and domain-specific cognitive function or, at the very least, serve in a protective capacity to stem potential future cognitive decline in this population. However, further large-scale randomized controlled trials that place emphasis on standardized reporting of exercise intervention characteristics and cognitive outcome measures are necessary to inform clinical practice.