5 Years of Exercise Intervention Did Not Benefit Cognition Compared to the Physical Activity Guidelines in Older Adults, but Higher Cardiorespiratory Fitness Did. A Generation 100 Substudy

Abstract

Background: Aerobic exercise is proposed to attenuate cognitive decline in aging. We investigated the effect of different aerobic exercise interventions and cardiorespiratory fitness (CRF) upon cognition throughout a 5-year exercise intervention in older adults.Methods: 106 older adults (52 women, age 70-77 years) were randomized into high-intensity interval training (HIIT; ∼90% peak heart rate), moderate-intensity continuous training (MICT; ∼70% peak heart rate), or control for 5 years. The HIIT and MICT groups performed supervised training twice weekly, while the control group was asked to follow the national physical activity guidelines (30 min of physical activity/day). At baseline, 1-, 3-, and 5-year follow-up, participants partook in cognitive testing (spatial memory, verbal memory, pattern separation, processing speed, working memory, and planning ability), underwent clinical testing, and filled out health-related questionnaires. Linear mixed models were used to assess the effects of the exercise group and CRF (measured as peak and max oxygen uptake) on each cognitive test. The effects of changes in CRF on changes in each cognitive test score throughout the intervention were also assessed. The associations between baseline CRF and cognitive abilities at the follow-ups were investigated using linear regressions.Results: There was no group-by-time interaction on the cognitive measures, and neither HIIT nor MICT participation was associated with better cognitive performance than control at any time point during the 5-year intervention. All groups increased their CRF similarly during the 1st year and subsequently declined back to baseline levels after 5 years. A higher CRF was associated with higher processing speed throughout the intervention while increasing CRF during the intervention was associated with better working memory and worse pattern separation. Higher CRF at baseline predicted consistently better processing speed and verbal memory performance.Conclusion: In this first 5-year randomized controlled trial investigating the effects of HIIT, MICT, and physical activity according to national guidelines on cognition, we observed no effect of exercise intervention group on cognition when compared to following the national physical activity guidelines. Still, the results showed that higher CRF and increasing CRF benefited multiple, but not all, cognitive abilities in older adults.Clinical Trial Registration:www.ClinicalTrials.gov, identifier [NCT01666340].

Leisure Time Physical Activities’ Association With Cognition and Dementia: A 19 Years’ Life Course Study

“…Our findings are comparable to findings in a prospective 5-year trial, where they used a different set of cognitive tests but tested the same cognitive domains as in our study ( Sokołowski et al, 2021 ). High and moderate intensive training programmes had no effect on cognition in a dementia-free population, but there was a positive effect from high cardiorespiratory fitness at baseline.…”

“…Furthermore, meta-analyses have shown that people with mild cognitive impairment have no significant increase in BDNF with exercise, even though there was a positive trend ( Ruiz-Gonzalez et al, 2021 ). In older adults without dementia, exercise programmes have also failed to show an effect on cognitive outcomes ( Sokołowski et al, 2021 ). However, those with high cardiorespiratory fitness at baseline, or those gaining high cardiorespiratory fitness, have shown improved cognitive abilities over a 5-year period ( Sokołowski et al, 2021 ), suggesting that those without dementia pathology benefits from being physically active, which in turn gives high respiratory fitness over the last 4 decades.…”

“…In older adults without dementia, exercise programmes have also failed to show an effect on cognitive outcomes ( Sokołowski et al, 2021 ). However, those with high cardiorespiratory fitness at baseline, or those gaining high cardiorespiratory fitness, have shown improved cognitive abilities over a 5-year period ( Sokołowski et al, 2021 ), suggesting that those without dementia pathology benefits from being physically active, which in turn gives high respiratory fitness over the last 4 decades. LTPA was first decreasing, whereas in the last 20 years, it was increasing for all age groups ( Morseth and Hopstock, 2020 ), while occupational physical activity has been decreasing ( Sagelv et al, 2020 ).…”

Five years of exercise intervention at different intensities and development of white matter hyperintensities in community dwelling older adults, a Generation 100 sub-study

“…Still, the FINGER study reported a positive effect of their multidomain intervention on processing speed in the participants with the largest structural brain reserve [29]. In our study cohort, processing speed was positively associated with VO 2peak across all participants, and increasing VO 2peak during the intervention improved working memory [30]. Taken together, this might suggest that interventions including exercise and/or physical activity provide brain functional benefits even if brain structural benefits cannot be detected.…”

Effects of a 5-Year Exercise Intervention on White Matter Microstructural Organization in Older Adults. A Generation 100 Substudy

“…This also shows that participants who did not reach VO 2max pushed themselves to their limit. Overall, the participants were cognitively intact and had stable cognitive abilities throughout the intervention ( Sokołowski et al, 2021 ). Over the course of the study, 2 participants died and 18 dropped out for unknown reasons.…”