BA: brain age, CA: chronological age; BAI=BA-CA, the smaller the younger brain

New research by Mass General Research Fellow An Ouyang, PhD, currently under review for publication, indicates that sleep and brain health are tightly linked, with improved sleep generally correlating with objective and subjective measures of improved brain health.

Healthy brain aging can be measured by the deviation of an individual’s brain activity from chronological age, conceptualized as brain age index (BAI) which was recently proposed by the McCance Center team using artificial intelligence (AI) technology and sleep electroencephalogram (EEG) data.

However, an effective approach of improving cognition and sleep-derived brain aging, is lacking. In research just concluded, the team hypothesized that an aerobic exercise regimen would improve brain health in a sedentary population, as reflected by improvement in cognition, and a reduction in sleep-based BAI.

The Clinical Trial

Current Study Design
We enrolled sedentary older adults without sleep complaints in the Greater Boston area to complete a 12-week moderate intensity exercise program with home wearable physical activity tracker and sleep monitor. The participants came to Massachusetts General Hospital to complete initial and post-intervention assessments to determine their brain health and physical fitness.

The Results

We found that the 150-minute weekly aerobic exercise program improved aerobic fitness and heart function as measured by resting and sleeping heart rate. Participants showed cognitive improvement in fluid intelligence, total cognition, pattern comparison processing speed and oral reading recognition. Moreover, analyses of home sleep data revealed a 3.59% increase in the percentage of time spent in deep sleep and confirmed that lower BAI was associated with less fragmented sleep and higher sleep efficiency.

We further found that the improvement of brain cognitive health was associated with the change of aerobic fitness. Also, our novel brain health biomarker BAI is related with brain processing speed which is able to differentiate healthy populations from dementia populations.

Conclusion: A recommendation for exercise, sleep to improve brain health

We concluded that 12 weeks of moderate-intensity aerobic exercise improves brain health and some measures of sleep quality in previously sedentary older adults. Importantly, our findings provide objective physiological evidence that exercise can improve sleep quality and brain health in older adults. Moreover, integrating novel analytics and home wearable devices for physiological tracking are promising approaches to track long-term brain health interventions for both healthcare providers and patients.