The Effects of Exercise on Sleep and Brain Health
The Effects of Exercise on Sleep and Brain Health
Brain health and cognitive functioning can be affected by aging. Exercise is a potentially
 effective method for promoting "successful brain aging" by improving cardiovascular fitness,
 brain function and possibly sleep quality. This project will measure the effects of exercise
 on brain health and attempt to develop a better way to track brain health, by measuring brain
 activity during sleep.
There exists a critical need to develop biomarkers of brain age and for scientifically proven
 interventions to improve brain health. Previously, a machine learning algorithm, the Brain
 Age Index (BAI), was developed to predict brain age (BA) based on 510 features derived from
 an overnight sleep EEG. The algorithm reports how old an individual's sleeping brain activity
 "looks", called the "brain age" (BA), and compares this with the chronological age (CA). The
 difference is the BAI: BAI = BA-CA. Prior work suggests that patients with significant
 neurological or psychiatric disease or hypertension and diabetes exhibit a mean excess brain
 age, or "brain age index" (BAI), of 4 and 3.5 years relative to healthy controls. Moreover,
 it has been shown that high BAI is an independent predictor of mortality. Each extra year of
 BAI yields a 3.3% relative increase in the risk of death. Work from other groups suggest that
 exercise is potentially effective for promoting "successful brain aging".

 Studies of exercise effects on cognition include a metanalysis of 18 prior studies that
 analyzed the results of exercise on cognitive function in older adults. It was found that
 aerobic fitness training improved performance across several cognitive domains, including
 executive function, cognitive control, spatial processing, and processing speed, with an
 average improvement across studies and across all domains of 0.5 standard deviations relative
 to controls. Improvement was greatest for executive and control processes. The degree of
 improvement was also related to the length of the ﬁtness-training intervention, duration of
 training sessions, and gender (females appeared to benefit more). Studies of exercise effects
 on brain structure include a prior study that enrolled 35 older adults (14 with Mild
 Cognitive Impairment, 16 healthy controls) to participate in a 12-week moderate-intensity
 walking program. Subjects' VO2max increased by an average of 8.49%. The degree to which
 cardiorespiratory fitness (V̇O2peak) improved due to the intervention was strongly positively
 correlated with widespread changes in cortical thickness. Taken together, these and other
 studies suggest that aerobic exercise may be an effective intervention to counteract cortical
 atrophy due to aging and disease and might provide protection against future cognitive
 decline in at-risk older adults.

 This study hypothesizes that cognitive performance will increase after 12 weeks of regular
 exercise (1a), EEG-based BAI will be lower after 12 weeks of regular exercise (1b), and
 improvements of cognitive measures are predictable from changes in BAI (1c). Additionally, it
 is hypothesized that an excess BAI will correlate with poor sleep quality, higher
 pre-existing comorbidities, poor diet, and small social network (2). Sedentary subjects who
 undergo the 12-week exercise training program are anticipated to show measurable improvements
 in EEG-based brain age and cognitive function, and that the degree of improvement will be
 related to the degree of improvement in aerobic fitness. This study will provide preliminary
 data to support a larger and longer longitudinal study designed to 1) Clinically validate
 novel, low-cost, and patient-friendly EEG-based biomarkers of brain health; and 2) Assess the
 effectiveness of interventions aimed at preserving and improving brain health and ultimately
 extending healthspan.
Inclusion Criteria:

 1. Sedentary (≤ two exercise sessions per week for the past 6 months)

 2. Aged 50 to 75 years old

 3. Cleared by primary care physician or other personal physician to participate in a
 12-week moderate-intensity walking exercise program. Clearance can be provided to one
 of the study investigators either verbally or in writing.

 Exclusion Criteria:

 1. History of neurological illness (e.g. poorly controlled epilepsy with >1 seizure per
 month in the last 6mo, stroke with residual motor language deficits, Multiple
 sclerosis, Parkinson's disease, clinically diagnosed dementia [defined as score <26 on
 the Mini-Mental State Examination], head trauma in the preceding 6-months with
 continued cognitive symptoms, cerebral palsy, brain tumor, normal-pressure
 hydrocephalus, HIV infection, or Huntington's disease)

 2. Untreated Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) Axis I
 disorders (i.e., severe depressive symptoms, substance abuse or dependence)

 3. Impaired activities of daily living (ADLs) measured by the Lawton and Brody
 Self-Maintaining and Instrumental Activities of Daily Living Scale.

 4. Inability to safely exercise or perform any of the tests

 5. Inability to perform the cognitive tests due to lack of English proficiency

 6. Known diagnosis of severe sleep apnea (apnea-hypopnea index ≥ 15/hour of sleep)

 7. Subject fails Cardiopulmonary Exercise Testing (CPET), i.e. develops symptoms such as
 shortness of breath, chest pain, palpitations, lightheadedness, or syncope during CPET
 testing

 8. Patients with a pacemaker or an automatic implantable cardioverter-defibrillator.