Brain Health Benefits Of Physical Activity
by Zvinka Zlatar, Assistant Professor, Department of Psychiatry UCSD
Our research focuses on developing novel non-pharmacological interventions to improve brain health in aging, leveraging mobile health (mHealth) technology (i.e., heart rate trackers, Fitbit, etc.) to track progress and provide feedback.
In the lab we conducted a small 12-week randomized controlled trial (Independent Walking for Brain Health) designed to test the feasibility of using a mHealth device to assist older adults to independently achieve and maintain physical activity guidelines (≥150 minutes per week of moderate intensity physical activity — MIPA) in their free-living environments to improve brain health. We were interested in learning if exercising independently, as opposed to in a lab based or supervised environment, would improve brain health and cognition.
Participants were randomly assigned to a Physical Activity or a Healthy Aging Education condition. Only the participants randomized to the Physical Activity condition received an individualized exercise prescription and a commercially available mHealth device. The mHealth device was a heart rate tracker, programmed through its smart phone application to set custom heart rate target zones equivalent to MIPA for each person.
The device was programed to vibrate and flash different colored lights when participants were deviating from their individually prescribed heart rate target zones. Participants did not need to have their smartphone with them during the exercise sessions, since data gathered from the mHealth device was later synced with the app and emailed to the study team. The study team provided weekly feedback about progress via email and phone calls using data gathered by the mHealth device. Participants were instructed to maintain MIPA by following the mHealth device prompts and attempting to walk above their minimum prescribed heart rate during each exercise session. This “just in time” feedback was hypothesized to help older adults achieve and maintain MIPA independently without the need for a supervisor/personal trainer.
We found that participants in the physical activity condition increased the time they spent in MIPA from 144 minutes per week at the beginning of the study, to 282 minutes per week by the end of the study, greatly surpassing the current physical activity guidelines for older adults. Accelerometer measurement corroborated that, by the end of the study, those in the physical activity group had ~18 minutes of MIPA per day, on average, compared to the control group. These are encouraging findings suggesting that using mHealth can really help older adults walk faster to achieve physical activity guidelines independently.
Most importantly, the intervention resulted in a significant increase in the total volume of the brain’s gray matter, suggesting that improving MIPA can help protect the brain from neurodegeneration. When we looked within the physical activity group, we saw that increased MIPA was associated with higher brain volume in the frontal lobe, an area of the brain that supports our executive functions (i.e., ability to inhibit irrelevant information, higher order reasoning, decision-making, mental flexibility). The increases in gray matter in the frontal lobe were associated with better executive function performance in those who exercised. Since the frontal lobe is one of the first areas of the brain to decline as we age, it is important to keep it healthy.
Our preliminary research suggests that the brain health benefits seen in lab-based studies can indeed be translated to real world contexts when using mHealth to help individuals maintain MIPA independently. These types of interventions have the potential to reach more individuals and overcome barriers such as lack of transportation to engage in physical activity.