Cardiorespiratory response to exercise testing in individuals with Alzheimer's disease

Objective: To examine exercise testing response in Alzheimer's disease (AD) and possible disease-related change over time.

Design: Retrospective assessment of a 2-year observational study.

Setting: University medical center.

Participants: Individuals without dementia (n=50) and with AD (n=31).

Interventions: Not applicable.

Main outcome measures: Participants underwent a clinical dementia evaluation and performed an incremental exercise test using a treadmill and the modified Bruce protocol at baseline and at a 2-year follow-up. We examined oxygen consumption, minute ventilation, heart rate, and ventilatory equivalents for oxygen and carbon dioxide at submaximal and peak exercise intensities to determine whether the measures were different between groups or over time.

Results: Participants with AD and those without dementia performed similarly at submaximal effort, and both groups showed similar changes in exercise response over 2 years. However, nondemented individuals had consistently higher values of oxygen consumption (P≤.02) and minute ventilation at peak effort at baseline (P=.003).

Conclusions: Individuals with AD demonstrate physiologic responses to submaximal exercise effort that are not significantly different than individuals without dementia. However, differences are apparent at the extreme of effort.