Exercise, fitness and cognition – A randomised controlled trial in older individuals: The DR’s EXTRA study - 27/10/10

Doi : 10.1016/j.eurger.2010.08.001

P. Komulainen ^a, M. Kivipelto ^b,^c, T.A. Lakka ^a,^d, K. Savonen ^a,^e, M. Hassinen ^a, V. Kiviniemi ^f, T. Hänninen ^g, R. Rauramaa ^a,^⁎,^e
^a Kuopio Research Institute of Exercise Medicine, Foundation for Research in Health Exercise and Nutrition, Haapaniementie 16, FIN-70100, Kuopio, Finland
^b Department of Neuroscience and Neurology, University of Eastern Finland, Kuopio Campus, Kuopio, Finland
^c Aging Research Center, Karolinska Institutet, Stockholm, Sweden
^d Institute of Biomedicine/Physiology, University of Eastern Finland, Kuopio Campus, Kuopio, Finland
^e Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Kuopio, Finland
^f Information Technology Centre, University of Eastern Finland, Kuopio Campus, Kuopio, Finland
^g Department of Neurology, Kuopio University Hospital, Kuopio, Finland

Corresponding author. Tel.: +358 440 37 5513; fax: +358 17 288 4488.

Abstract

Background

Observational studies suggest that higher levels of physical activity and cardiorespiratory fitness associate with improved cognition. However, evidence from randomised controlled trials (RCT) is limited. We hypothesised that increased regular exercise improves cognition in older individuals. The trial is registered: ISRCTN45977199 (isrctn.org/).

Methods

A population sample of 1335 men and women aged 57–78 years was randomised into aerobic exercise, resistance exercise, diet, combined aerobic exercise and diet, combined resistance exercise and diet or reference group for a 4-year intervention. Here, we report 2-year interim data. Exercise was assessed by a questionnaire and by maximal oxygen uptake (VO_2max), an objective measure of exercise, and cognition using Consortium to establish a registry for Alzheimer’s disease (CERAD) neuropsychological tests.

Findings

In the intention to treat analyses, regular exercise increased in exercise groups, but remained unchanged in reference and diet only groups (P<0.001 between groups). VO_2max remained unchanged in exercise groups, but decreased in reference and diet only groups (P<0.001 between groups). There were between group differences neither in cognition, nor in the association of VO_2max to cognition during the first 2 years of intervention. In secondary analyses, improved VO_2max was associated with improved immediate memory in aerobic (β=0.11, P=0.001), resistance (β=0.08, P=0.018), diet (β=0.09, P=0.029) and combined aerobic and diet groups (β=0.09, P=0.013), with improved delayed memory in diet group (β=0.08, P=0.015) and with verbal performance in aerobic group (β=0.14, P=0.044). Those who were in the upper gender-specific VO_2max tertile had a 66.0% (95% confidence interval [CI] 34.2–82.4%, P=0.001) lower, and those in the middle tertile a 56.4% (95% CI 22.6–75.4%, P=0.005) lower risk of developing impaired delayed memory compared to those in the lower VO_2max tertile, after adjusting for potential confounders.

Conclusions

Present data from a large RCT among older individuals failed to show between group differences on the effects of regular exercise on cognition. However, secondary analyses suggest that higher levels of fitness may potentially mitigate memory impairment.

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Keywords : Ageing, Physical exercise, Cognitive function, Memory, Randomised controlled trial