| dc.description.abstract | Background: Physical exercise that improves cardiorespiratory fitness (CRF) has been shown to enhance cognition in older adults. However, evidence of the long-term benefits of a high CRF on cognition remains inconsistent. Drawing data from a large 5-year exercise intervention trial with a total of 7 years of follow-up for cognition, we investigated the association between CRF and cognition as well as the effect of the longitudinal change in CRF on cognition in healthy older adults.
Method: We included 770 non-demented and cognitively healthy older adults (mean age at baseline, SD, 72.0 years, 2.0; 367 females). The participants in the present study belonged to the Generation 100 Study and had complete data on CRF and important confounders for cognition (educational attainment, age, sex, and subjective memory complaints) at baseline and after 1 year, and 3 years. CRF was assessed directly as maximal oxygen uptake using ergospirometry. Cognition was assessed using the Montreal Cognitive Assessment (MoCA) at year -3, - 5, and -10 (counting from baseline). Linear mix models (LLM) were used to assess the association between CRF at baseline and change in CRF after 1 year, and 3 years and cognition over 7 years.
Results: All participants' mean (SD) baseline CRF level was 30.3 (6.5) mL/kg/min. On average, men achieved a higher CRF at baseline compared to women (p<0.001) (mean, SD, 32.9 mL/kg/min, 6.5; 27.3 mL/kg/min, 5.0, respectively). After 1 year, the mean VO2peak increased by 1.8 mL/kg/min (SD 3.6, p<0.001, 95% CI 1.5, 2.0). However, by year 3, the mean VO2peak was not different compared to the baseline (mean difference, SD, 0.2 mL/kg/min, 4.1, p=0.224, 95% CI -0.5, 0.1). The mean (SD) MoCA score at year -3, -5, and -10 was 25.3 (3.0), 25.0 (3.0), and 24.8 (3.2), respectively. From LLMs, neither a 1-year (estimated coefficient 0.022, p=0.471) nor a 3-year (estimated coefficient 0.041, p= 0.116) change in CRF predicted MoCA scores over 7 years. However, each unit (mL/kg/min) higher in CRF at baseline predicted an additional 0.054 points on the mean MoCA score over 7 years (p<0.001). In analyses stratified for other confounders of cognition, this association remained significant.
Conclusion: We found no association between change in CRF after 1 year or 3 years and cognition in healthy older adults. However, a higher baseline CRF predicted better cognition over 7 years. Therefore, improving and maintaining physical fitness earlier in life and carrying it into old age might benefit cognitive aging. | |