The overall goal of the proposed study is to evaluate the effects of an 8-week aerobic exercise program on cognition and determine the relationship between cognitive improvements and Transcranial Magnetic Stimulation (TMS) neuroplasticity. The investigators will also explore the effect modification of BDNF levels and BDNF allelic status, and APOE4 status on cognitive response after exercise.
Name: Aerobic Exercise
Description: Participants will be fitted with a heart rate monitor and will be instructed to walk (or trot) to maintain 55-64% of maximal heart rate (determined by exercise test) for the first 4-weeks of exercise or to maintain 65-90% of maximal heart rate (determined by exercise test) for the second 4-weeks of exercise during each session.Type: BehavioralExercise group
Description: An index of the duration of the Theta-Burst Stimulation (TBS) induced modulation of corticospinal excitability (the time-point at which the normalized mean Motor Evoked Potential (MEP) amplitude returns to baseline values) will be defined for each participant.
Measure: Change in TMS Plasticity Measures Time: baseline and after 8 weeks of exerciseDescription: Cognitive performance will be assessed using a neuropsychological test battery in executive function, processing speed, learning, and language.
Measure: Change in Cognitive Performance Time: baseline and after 8 weeks of exerciseDescription: Blood samples will be collected for BDNF levels.
Measure: Changes in BDNF Levels Time: baseline and after 8 weeks of exerciseDescription: A maximal treadmill test will be performed to determine maximal oxygen uptake (VO2) as a measure of aerobic capacity.
Measure: Change in Aerobic Capacity (Cardiovascular Fitness) Time: baseline and after 8 weeks of exerciseDescription: Genetic testing will be performed to assess for brain-derived neurotrophic factor (BDNF) Val66Met polymorphism.
Measure: Allelic Status BDNF Time: baselineDescription: Genetic testing will be performed to assess for the presence of apolipoprotein-E (APOE) e4 allele.
Measure: Allelic Status APOE Time: baselineSingle Group Assignment
There is one SNP
Genetic testing will be performed to assess for brain-derived neurotrophic factor (BDNF) Val66Met polymorphism.. Allelic Status APOE. --- Val66Met ---