The Effects of Exercise on Sleep and Brain Health
Condition: Aging; Sleep Disorder
MeSH terms: Sleep Wake Disorders
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Moderate-Intensity Exercise
Intervention type(s): Behavioral
Intervention description(s): See description of study arm.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Cardiovascular; Neuroscience; Exercise