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Researchers at University of Tsukuba reports new findings in the field of exercise and brain health. Their latest study revealed that hippocampal neurons, which are crucial in memory, are activated by exercise in an intensity-dependent manner, from very light to vigorous intensity. The current findings build on previous investigations by the team and highlight the potential benefits of developing exercise programs that are accessible to everyone.

Tsukuba, Japan—Recent studies have shown that exercise stimulates the hippocampus, a brain region associated with memory, and may help prevent dementia. Many health and exercise guidelines often recommend moderate to vigorous exercise for health promotion; however, such levels of activity can be challenging to sustain for people of all ages and fitness levels. The research team have thus investigated the benefits in detail. The team's study demonstrated that even exercise classified as "light intensity" or "very light intensity" can enhance hippocampal function. However, the detailed relationship between exercise intensity and hippocampal activation has not been thoroughly investigated.

Therefore, the researchers established a rat treadmill exercise model based on the American College of Sports Medicine exercise prescription guidelines, which classify exercise into very light, light, moderate, and vigorous categories and are widely used in human exercise programming. Using this rat exercise model, the team examined the relationship between exercise intensity and hippocampal neuronal activation. Their findings confirmed that hippocampal neuronal activity increases with exercise intensity and is activated even by light-intensity exercise. Specifically, the dentate gyrus and CA1 regions of the hippocampus were activated, even by very-light-intensity exercise, which is below the levels typically emphasized in exercise guidelines.

These results demonstrate the intensity-dependent activation of hippocampal neurons, with very-light-intensity exercise as the minimum intensity required for activation. This study provides fundamental data for developing exercise prescription guidelines targeting the hippocampus. Furthermore, the findings support the research team's previous conclusions that light exercise can effectively enhance hippocampal function. The results are expected to contribute to the promotion of light exercise-based programs, which are accessible for older adults and individuals with low physical fitness.

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This research was supported in part by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) granted to the "Human High Performance (HHP) Research Project" (1111501004) (to H.S.); KAKENHI Grants-in-Aid for Scientific Research (A) (23240091; 15H01828; 24H00670) (to H.S.); and the Japan Science and Technology Agency (JST)-Mirai Program (JPMJMI19D5) (to H.S.).

Original Paper

Title of original paper:

Very-light-intensity exercise as minimal intensity threshold for activating dorsal hippocampal neurons: Evidence from rat physiological exercise model

Journal:

Biochemical and Biophysical Research Communications

DOI:

10.1016/j.bbrc.2024.151243

Correspondence

Visiting Professor SOYA Hideaki
Center for Cybernics Research, University of Tsukuba
Professor Emeritus, Institute of Health and Sport Sciences, University of Tsukuba

Related Link

Institute of Health and Sport Sciences

Center for Cybernics Research