Authors: Kay L Cox, Nicola T Lautenschlager
Published: 2020-12-07
DOI: 10.1002/alz.040752
Source: Full article
AbstractBackgroundThe evidence supporting the view that physical activity (PA) and exercise training in particular aerobic or resistance training improves cognition for those with mild cognitive impairment (MCI) is accumulating. ‘PA’ usually refers to any bodily movement whereas ‘exercise’ refers to planned and/or structured activity which may be aerobic exercise, resistance training or a combination (multimodal) or mind‐body exercise. Systematic reviews and meta‐analyses report inconsistent results, highlighting methodological issues including variations in study design; the type duration and frequency of the exercise utilised; the cognitive outcome and the heterogeneity of the target group. In order to minimise the effects of these issues, in utilising the treatment framework, we limited our summary to focus on the effects of aerobic training and resistance training separately on cognition in participants 60 years and over with MCI.MethodSeveral databases were searched to identify systematic reviews or meta‐analyses of RCT’s conducted in the last 5 years evaluating the effects of aerobic or resistance exercise on cognition. Reviews relevant to each regime were summarised to identify the ingredients and dosing parameters.ResultsFive systematic reviews and meta‐analyses reported positive effects of aerobic exercise on global cognition with small to medium effect sizes and one with weak significant benefits on memory. Session duration ranged between 20‐60 minutes, frequency between 2‐5 times/week and intensity between 60‐80% of maximum heart rate. The evidence for resistance training is more limited with 4 recent reviews. Evidence for global cognition with small to moderate effects was strongest with limited effects for executive function. Higher intensity and more frequent sessions appear to be more effective but have low adherence rates. Formats are progressive using one’s own body weight, free weights, dumbbells, resistance bands, weight machines or a combination, supervised with sessions of 60‐75 minutes in duration 2‐3 times/week.ConclusionThe evidence for an effect of aerobic training on cognition is growing and the evidence for resistance training is promising. Refinement of the treatment specifications for optimal cognitive outcomes requires further investigations of interventions with clearly defined mode, frequency, duration and intensity of exercise and crucial reports of adherence to the treatment.