Exercise or physical activity and cognitive function in adults with type 2 diabetes, insulin resistance or impaired glucose tolerance: a systematic review

Abstract

BackgroundDiabetes is an important risk factor for cognitive impairment. Although some studies suggest that physical exercise can minimize age-related cognitive declines or improve brain morphology or function, benefits in diabetes or impaired glucose tolerance are unclear. Therefore, our aim was to evaluate the efficacy of exercise or physical activity on cognition in adults with type 2 diabetes, insulin resistance or impaired glucose tolerance.MethodsAn electronic search for studies published from the earliest record until February 2017 was conducted using Medline, EMBASE, SPORTDiscus, CINAHL, and PsycINFO. Any experimental or observational study designs were included, as long as they were conducted in individuals of any age with type 2 diabetes, insulin resistance or impaired glucose tolerance, and they directly examined exercise/physical activity effects on cognitive outcomes or the relationship between changes in cognition and changes in either insulin resistance and glucose homeostasis. Study quality was assessed using the PEDro scale; data on participant and intervention characteristics and outcomes were extracted.ResultsSix studies enrolling 2289 participants met the eligibility criteria. Quality was modest and effect sizes variable and mostly small or negligible. Overall, four of the six studies (67%) reported significant benefits of greater exercise/physical activity participation for some aspects of cognition, but only 26% of cognitive outcomes were significant across all trials. Clinical improvements in insulin resistance/glucose homeostasis were related to improvements in cognitive function in three studies. Overall results were inconsistent, with benefits varying across exercise types and cognitive domains.ConclusionsLiterature does not provide evidence that physical activity or exercise interventions contribute to a better cognitive function in patients with type 2 diabetes or impaired glucose tolerance. Large-scale, long-term, robust randomized controlled trials are required to determine if exercise improves cognition in this high-risk cohort, and to investigate putative mechanistic links between cognition, body composition, metabolism, and inflammation in diabetes and related metabolic syndromes.

Changes in Cognitive Function and in the Levels of Glycosylated Haemoglobin (HbA1c) in Older Women with Type 2 Diabetes Mellitus Subjected to a Cardiorespiratory Exercise Programme

“…However, it is globally estimated that 27% of cases of DM2 are caused by physical inactivity [27]. Furthermore, the literature does not provide complete evidence to assert that physical activity or exercise interventions contribute to improving the cognitive functioning of patients with DM2 or glucose intolerance [28]. The studies published to date on this topic do not seem to be sufficient to conduct a complete evaluation of the effects of non-pharmacological interventions to improve the cognition of DM2 patients [29].…”

Effectiveness of Virtual Reality Systems to Improve the Activities of Daily Life in Older People

“…The risk of bias for functional mobility and transfers was high ( Figure 3 ). In functional ambulation, four studies had a high risk of bias for random sequence generation [ 35 , 48 , 49 , 50 ], none of the studies could blind participants, only six blinded outcome assessors [ 37 , 38 , 41 , 47 , 51 , 52 ] and only one had a low risk of bias for allocation concealment. On the other hand, loss to follow-up was significant in only one study (Keogh et al, 2014).…”

“… Farzin 2018 [ 39 ] Level I ECA N = 25 55 (51–59) 68% Female >55 years; absence of a) history of neurological impairments, b) psychiatric disorders, c) learning disabilities, d) cerebrovascular disease Older Adult University Program Kuala Lumpur, Malaysia Virtual Week Board Game 6 weeks 1 time/week Usual routine activities GAS; IADL; PRMQ; PMT 4 and 12 weeks after the intervention VWB training improved performance and activities of daily living and reduce depression and anxiety levels. Htut [ 51 ] Level I RCT n = 84 EC:VR = 21 EC:BE = 21 EC:PE = 21 CC = 21 75 (70–80) 37% female 65–85 years MEC > 23 BI = 100 Residential aged-care Yangon, Myanmar Xbox Kinect Cognitive Stimulation Balance exercise 8 weeks 3 times/week Without intervention TUG; 5 TST FES; MoCA BBS No follow-up VR group improved both physical and cognition performance, while BE was effective in enhancing cognition. VR and BE may help fall concern in older persons.…”

Management of Older People With Diabetes - A Focus On Mental Functions

“…In the Look AHEAD (Action for Health in Diabetes) study of 5,145 participants with type 2 diabetes, mean (SD) age 58.7 (6.8) years equally randomised to intensive life style intervention (ILI) or usual care, ILI significantly reduced the incidence of depressive symptoms (HR 0.85, 95% CI 0.75 to 0.97, P=0.02) and preserved better function in the intervention group (P <0.01) although it did not improve cognitive function [54,55]. A recent meta-analysis to evaluate the efficacy of exercise or physical activity on cognition in adults with type 2 diabetes, did not demonstrate clear results and concluded that large-scale randomised trials are still required [56]. Tai chi, which involves a series of slowly, performed dance like postures may have a potential beneficial effects in improving general wellbeing and reducing depressive symptoms [57].…”