title: Aerobic exercise improves cognition for older adults with glucose intolerance, a risk factor for Alzheimer's disease.
abstract: Impaired glucose regulation is a defining characteristic of type 2 diabetes mellitus (T2DM) pathology and has been linked to increased risk of cognitive impairment and dementia. Although the benefits of aerobic exercise for physical health are well-documented, exercise effects on cognition have not been examined for older adults with poor glucose regulation associated with prediabetes and early T2DM. Using a randomized controlled design, twenty-eight adults (57-83 y old) meeting 2-h tolerance test criteria for glucose intolerance completed 6 months of aerobic exercise or stretching, which served as the control. The primary cognitive outcomes included measures of executive function (Trails B, Task Switching, Stroop, Self-ordered Pointing Test, and Verbal Fluency). Other outcomes included memory performance (Story Recall, List Learning), measures of cardiorespiratory fitness obtained via maximal-graded exercise treadmill test, glucose disposal during hyperinsulinemic-euglycemic clamp, body fat, and fasting plasma levels of insulin, cortisol, brain-derived neurotrophic factor, insulin-like growth factor-1, amyloid-β (Aβ40 and Aβ42). Six months of aerobic exercise improved executive function (MANCOVA, p=0.04), cardiorespiratory fitness (MANOVA, p=0.03), and insulin sensitivity (p=0.05). Across all subjects, 6-month changes in cardiorespiratory fitness and insulin sensitivity were positively correlated (p=0.01). For Aβ42, plasma levels tended to decrease for the aerobic group relative to controls (p=0.07). The results of our study using rigorous controlled methodology suggest a cognition-enhancing effect of aerobic exercise for older glucose intolerant adults. Although replication in a larger sample is needed, our findings potentially have important therapeutic implications for a growing number of adults at increased risk of cognitive decline.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA. ldbaker@uw.edu
authors.forename: Laura D
authors.initials: LD
authors.lastname: Baker
authors.forename: Laura L
authors.initials: LL
authors.lastname: Frank
authors.forename: Karen
authors.initials: K
authors.lastname: Foster-Schubert
authors.forename: Pattie S
authors.initials: PS
authors.lastname: Green
authors.forename: Charles W
authors.initials: CW
authors.lastname: Wilkinson
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
authors.forename: Brenna A
authors.initials: BA
authors.lastname: Cholerton
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Plymate
authors.forename: Mark A
authors.initials: MA
authors.lastname: Fishel
authors.forename: G Stennis
authors.initials: GS
authors.lastname: Watson
authors.forename: Glen E
authors.initials: GE
authors.lastname: Duncan
authors.forename: Pankaj D
authors.initials: PD
authors.lastname: Mehta
authors.forename: Suzanne
authors.initials: S
authors.lastname: Craft
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000209:etiology*; D016229:Amyloid beta-Peptides / Q000097:blood; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood; D003072:Cognition Disorders / Q000209:etiology* / Q000534:rehabilitation*; D056344:Executive Function / Q000502:physiology; D015444:Exercise; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D015309:Glucose Clamp Technique / Q000379:methods; D018149:Glucose Intolerance / Q000150:complications* / Q000534:rehabilitation; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010101:Oxygen Consumption / Q000502:physiology; D012307:Risk Factors
chemical_list: D016229:Amyloid beta-Peptides; D019208:Brain-Derived Neurotrophic Factor; D007334:Insulin-Like Growth Factor I