A recent study explored the impact of different exercise levels on the hippocampus, a brain region essential for memory consolidation, in healthy older adults.

The research revealed that participants who engaged in high-intensity interval training (HIIT) experienced significant improvements in hippocampal function.

Remarkably, these benefits persisted for up to five years after the exercise intervention began!

<h3>Can Exercise Improve Brain Function?</h3>

This study, a randomized controlled trial, investigated how different levels of exercise intensity affect brain function in older adults. A total of 194 participants, aged 65 to 85, were recruited. Individuals with a history of brain trauma or heart and brain surgery, as well as those at high risk for heart events during exercise, were excluded. All participants were free of diagnosed mental illnesses or cognitive decline at the start of the study.

Participants were divided into three groups based on exercise intensity:

<b>Low-intensity training</b>: Included activities like stretching, range-of-motion exercises, and balance training.

<b>Medium-intensity training</b>: Involved continuous treadmill walking.

<b>High-intensity training</b>: Focused on treadmill intervals that pushed the heart rate higher than in the medium-intensity group, and combined aerobic with anaerobic exercises.

Each group exercised three days a week for six months, under the supervision of exercise physiologists. To assess cognitive and hippocampal function, participants underwent tests like the hippocampal-dependent paired-associate learning (PAL) test. Monthly blood samples were also taken to gather biomarker data. Cognitive tests were performed monthly during the intervention, and participants were followed up every six months for up to five years.

<h3>How Does Exercise Intensity Affect Cognitive Improvement?</h3>

The study's findings revealed that the high-intensity interval training (HIIT) group showed significant improvement in hippocampal-dependent spatial learning, while the low and medium-intensity groups maintained stable performance without any notable improvement. Remarkably, these cognitive gains were sustained during the five-year follow-up period, and the improvements appeared to be independent of lifestyle or physical activity changes during that time.

Participants who initially scored poorly on the paired-associate learning (PAL) test saw the most significant gains in the HIIT group. While those in the medium-intensity group also showed some improvement, the gains were less pronounced. Additionally, the HIIT group exhibited a stable right hippocampal volume, while the other groups showed a decrease in this brain region.

When examining other brain areas, researchers found that the high and medium intensity groups had healthier brain structures compared to the low-intensity group. The HIIT group also demonstrated improved functional connectivity between multiple neural networks. However, no group showed improvements in network connectivity when assessed at the 12-month mark.

Moreover, changes in certain biomarkers in the HIIT group were linked to better performance in the PAL test. However, the exercise interventions did not show improvements in working memory or emotional recognition. The results underscore the potential cognitive benefits of exercise, especially for those engaging in high-intensity interval training.