News & Research

    VA Puget Sound Health Care System and the University of Washington School of Medicine, Seattle, Washington

Effects of aerobic exercise on cognition for memory-impaired older adults with prediabetes

General Research Subject: Insulin Resistance Pre Diabetes

Focus: Exercise\Human, Insulin Action\Insulin Resistance

Type of Grant: Henry Becton Innovation

Project Start Date: January 1, 2011

Project End Date: December 31, 2012

Research Description

Cognitive benefits of aerobic exercise have not been examined for older prediabetic adults who are at increased risk of cognitive decline. The proposed pilot study will test the hypotheses that six months of moderate intensity aerobic exercise will improve cognitive abilities and disease-related biological processes for a vulnerable group of older prediabetic adults who are at increased risk of developing Alzheimer's disease (AD).  Using a randomized controlled design, 30 adults (>55 yrs) with prediabetes and pre-clinical AD will be enrolled and randomized to a brisk walking or stretching control group. Activities will be completed in small groups and supervised by a fitness trainer 4x/wk for 45-60min/session. Before and after the 6-month intervention, blood will be collected, and subjects will complete cognitive testing, a brief fitness test, and an oral glucose tolerance test to estimate insulin sensitivity.

For subjects who opt to enroll in the brain biomarker substudy, spinal fluid will be collected. Cognitive outcomes will include performance measures on tests of executive function that involve attention, organization, and multi-tasking, as well as on tests of verbal short-term memory. Biomarkers will include insulin sensitivity, fasting levels of insulin, glucose, cortisol, brain-derived neurotrophic factor, c-reactive protein, and beta-amyloid. The results of this pilot trial will provide novel data to indicate whether aerobic exercise improves cognition for a vulnerable group of older adults, and will set the stage for larger trials to further examine potential protective and disease-modifying effects of aerobic exercise in the brain.

Research Profile

What area of diabetes research does your project cover?  What role will this particular project play in preventing, treating and/or curing diabetes?

We will examine benefits of aerobic exercise on cognition and biomarkers of brain function for a vulnerable group of older (55+ yrs) adults with prediabetes and mild cognitive impairment (MCI), adults who are at high risk not only of developing type 2 diabetes but also Alzheimer's disease (AD). In two separate previous studies, we have shown that aerobic exercise improves cognitive function for older adult with prediabetes, and that aerobic exercise improves cognitive function for older adults with MCI. Prediabetes is a known risk factor for the development of AD, and adults with the double hit of prediabetes and MCI represent a fast-growing segment of the older adult population.

Aerobic exercise has many benefits for physical health and glucose metabolism, benefits that reduce risk of developing diabetes. If we are able to demonstrate that aerobic exercise also improves cognition and biomarkers of brain function, these findings could provide additional evidence to support aerobic exercise as a multi-factorial disease-modifying intervention with ultimate consequences for standard of preventive care. 

If a person with diabetes were to ask you how your project will help them in the future, how would you respond?

Although our project will examine the cognitive benefits of aerobic exercise for adults with prediabetes, our findings will have relevance to patients who meet diagnostic criteria for type 2 diabetes. We hope to demonstrate that aerobic exercise improves cognitive function and favorably alters biomarkers of brain function and diabetes. Although we will need to explore whether exercise can have the same effects for other adults in future studies, at present we have no scientific evidence to suggest that aerobic exercise would not also have similar effects on brain function for adults with well-controlled diabetes. 

Why is it important for you, personally, to become involved in diabetes research?  What role will this award play in your research efforts?

In my research, I have studied the link between type 2 diabetes and Alzheimer's disease (AD) for over 10 years. Adults with diabetes are at extremely high risk of developing AD. Type 2 diabetes is a disease that can be slowed or prevented, particularly with lifestyle interventions such as diet and exercise. Given this link between diabetes and AD, and in the absence of disease-modifying treatments for AD, it is important to examine whether AD can also be slowed or prevented using diabetes interventions.

Aerobic exercise has favorable effects on many body processes that are disrupted or harmed by diabetes without the side effects that accompany pharmaceutical interventions. Thus aerobic exercise may offer one viable therapeutic strategy to reduce risk of progression not only to diabetes but also to AD. Our project will examine the potential benefits of a 6-month trial of aerobic exercise on cognition and biomarkers of diabetes and Alzheimer pathology for older adults with prediabetes and pre-clinical AD. Our findings will tell us whether aerobic exercise improves brain function for adults at high risk of cognitive decline, and if confirmed, could have important implications for diabetes and Alzheimer's disease prevention.   

In what direction do you see the future of diabetes research going?

In light of statistics linking type 2 diabetes and Alzheimer's disease, the future of diabetes research must include studies examining the ultimate cognitive consequences of diabetes and the potential mechanisms that might account for the diabetes-Alzheimer link. This area of research is critical in light of escalating prevalence rates of prediabetes and diabetes in the United States, rates that also translate into increased prevalence of Alzheimer's disease. Aerobic exercise is a potent intervention to prevent progression from prediabetes to diabetes, and as a consequence may prevent cognitive decline and dementia for adults with frank or ensuing type 2 diabetes. The social and economic implications of a diabetes-Alzheimer co-morbidity will be astounding if efficacious interventions cannot be identified and effectively implemented in the interest of disease prevention.