Dr Jill Barnes, an expert on the brain and exercise from the University of Wisconsin-Madison, discusses the effect of exercise on cognitive function, brain blood flow, dementia risk, and progression. Topics include measuring brain blood flow, regional blood flow in the brain, the relationship between exercise intensity and brain health, resistance training and cognitive function, the impact of exercise on brain endothelial function, and exercise's influence on the risk of stroke and dementia.
Exercise can increase blood flow in the brain, with moderate-intensity exercise leading to a slight increase and high-intensity exercise potentially causing a decrease in blood flow.
Exercise interventions combining aerobic and high-intensity exercise have shown positive effects on brain health, particularly in increasing fitness levels.
The exact mechanisms by which exercise improves brain health include improved endothelial function, increased neuroplasticity, and enhanced neurovascular coupling.
The intensity of exercise plays a crucial role in promoting brain health, with moderate-intensity exercise increasing blood flow while high-intensity exercise may lead to a decrease in blood flow.
Deep dives
Exercise and Blood Flow in the Brain
Exercise is known to increase blood flow in the brain, with studies showing that moderate-intensity exercise leads to a slight increase in blood flow while high-intensity exercise can cause a decrease in blood flow. The response is quick, with an increase in velocity of blood flow within seconds of starting exercise. Fitness levels and exercise history also play a role, with individuals who are more fit or have a history of exercise showing higher baseline blood flow in the brain. However, it is important to note that the increase in blood flow may not translate to improved cognitive function directly. The brain has the ability to auto-regulate blood flow, ensuring it remains relatively constant despite changes in exercise intensity or other factors. More research is needed to understand the specific mechanisms by which exercise affects blood flow in the brain and its implications for cognitive function.
Exercise and Chronic Changes in the Brain
Exercise interventions have shown positive effects on brain health, including improvements in functional connections, cognitive function, and blood flow. One-year-long interventions that combined aerobic and high-intensity exercise demonstrated benefits, particularly in increasing fitness levels, as measured by VO2 max. Higher intensity workouts are likely better for stimulating cardiovascular responses and improving brain health. It should be noted that cognitive improvements may not be solely attributed to blood flow changes, as other factors such as neuroplasticity and improved neurovascular coupling might play a role. Resistance training has also shown promise in cognitive enhancement, although its effect on blood flow responses in the brain is not well-studied.
Mechanisms of Exercise on Brain Health
The exact mechanisms by which exercise improves brain health are not fully understood. Some potential factors include improved endothelial function, increased neuroplasticity, and heightened neurovascular coupling. Exercise has been shown to enhance endothelial function in peripheral blood vessels, leading to better blood flow regulation. In the brain, exercise may promote neuroplasticity, the ability of the brain to reorganize and form new connections. This can enhance cognitive function. Additionally, exercise might improve neurovascular coupling, the relationship between neural activity and blood flow regulation in the brain. Through these various mechanisms, exercise appears to have a positive impact on brain health, but further research is needed to fully understand the underlying processes.
Exercise Intensity and Brain Health
The intensity of exercise plays a crucial role in promoting brain health. While moderate-intensity exercise has been shown to increase blood flow in the brain, high-intensity exercise may lead to a decrease in blood flow due to the removal of excess carbon dioxide. It is suggested that exercise at an intensity sufficient to increase fitness levels is important for stimulating cardiovascular responses and yielding cognitive benefits. Multimodal interventions, combining aerobic and resistance training, have demonstrated cognitive enhancements in middle-aged and older adults. These findings underscore the importance of incorporating various exercise intensities to optimize brain health.
Exercise and Endothelial Function in the Cerebral Vessels
Regular exercise may improve endothelial function in the cerebral vessels, potentially contributing to reduced risk of stroke and cognitive decline. While specific mechanisms and measurements for cerebral endothelial function are still being explored, data suggests that exercise is associated with improved endothelial function and VO2 max. The impact of exercise on reducing the risk of stroke is harder to determine due to various types and causes of stroke. Exercise may also help prevent mini strokes and brain damage by improving blood flow and reducing cardiovascular risk factors.
Exercise and Risk of Alzheimer's and Dementia
Exercise shows promise in reducing the risk and slowing the progression of Alzheimer's and dementia, particularly in the context of overall cardiovascular health. Studies suggest that exercise can enhance cerebral blood flow, promote neuroplasticity, and impact factors like BDNF (brain-derived neurotrophic factor) linked to Alzheimer's disease. It may also aid in clearing waste products from the brain and maintaining cognitive reserve. However, the specific effects of exercise on different types of dementia and the role of factors like diet in brain health still require further research.
Exercise and Mental Health
Exercise has been associated with reducing anxiety and depression, although the exact mechanisms are not yet fully understood. Improved sleep quality due to exercise may contribute to its positive effects on mental health. However, more research is needed to definitively establish the relationship between exercise and mental health outcomes. While anecdotal evidence suggests exercise can benefit mood, the available literature and data are not sufficient to draw concrete conclusions regarding exercise's impact on mental health.
Dr Glenn McConell chats with Associate Professor from the University of Wisconsin-Madison, USA. Jill is an expert on the brain and exercise. We discussed the effect of acute (one bout) and chronic physical activity/ exercise on cognitive function, brain blood flow (BBF), dementia/Alzheimer’s disease risk and progression etc. A very interesting chat. Twitter: @Barnes_Lab 0:00. Introduction and welcome 2:01. How Jill got into exercise research 4:25. Studying with Hiro O. Tanaka 6:00. Researching with Michael Joyner 7:45. How measure brain blood flow (BBF) 10:00. Blood vessels that supply the brain and blood flow 19:16. What would look at if had unlimited funding? 20:32. BBF vs glucose use in the brain 21:30. Regional blood flow in the brain 22:40. Does BBF increase during exercise? 24:40. Blood pressure and regulation of brain blood flow 29:00. Effect of exercise intensity in BBF 32:25. Hypnosis/anticipatory rises in BBF 34:30. BBF distribution has not been examined much during exercise 37:00. Cognitive tests and BBF 38:00. Why does BBF decrease during very intense exercise? 41:00. Central fatigue and BBF 42:30. Exercise training and BBF 45:00. BBF and cognitive function 46:20. How quickly does BBF increase with exercise? 47:25. Fitness and BBF at rest 49:55. Cognition and exercise/lifestyle 51:44. Exercjse intensity and the brain 53:10. Resistance training and cognitive function 55:07. Exercise and brain endothelial function 57:10. Exercise and the risk of stroke 59:35. Exercise and the risk of dementia/Alzheimers disease 1:02:14. Exercise and mental health 1:03:45. Diet and BBF/brain health 1:06:15. Sex differences in BBF 1:12:57. Age and BBF 1:15:20. Fitness/strength and cognition etc 1:16:10. Erythropoietin, hemoglobin and cognitive function. 1:18:48. Exercise and myokines, BDNF, exosomes 1:21:10. Neurogenesis and exercise 1:22:20. Exercise, cognition and hypertension/diabetes 1:25:00. Prevention of Alzheimer’s disease/dementia 1:27:00. Exercise intensity and mode of exercise 1:29:55. BBF during resistance exercise 1:31:20. Controversies in the field 1:34:52. Keep things simple re exercise 1:37:00. Takeaway messages 1:39:57. Outro
Inside Exercise brings to you the who's who of research in exercise metabolism, exercise physiology and exercise’s effects on health. With scientific rigor, these researchers discuss popular exercise topics while providing practical strategies for all. The interviewer, Emeritus Professor Glenn McConell, has an international research profile following 30 years of Exercise Metabolism research experience while at The University of Melbourne, Ball State University, Monash University, the University of Copenhagen and Victoria University. He has published over 120 peer reviewed journal articles and recently edited an Exercise Metabolism eBook written by world experts on 17 different topics (https://link.springer.com/book/10.1007/978-3-030-94305-9). Connect with Inside Exercise and Glenn McConell at: Twitter: @Inside_exercise and @GlennMcConell1 Instagram: insideexercise Facebook: Glenn McConell LinkedIn: Glenn McConell https://www.linkedin.com/in/glenn-mcconell-83475460 ResearchGate: Glenn McConell Email: glenn.mcconell@gmail.com Subscribe to Inside exercise: Spotify: shorturl.at/tyGHL Apple Podcasts: shorturl.at/oFQRU YouTube: https://www.youtube.com/@insideexercise Anchor: https://anchor.fm/insideexercise Google Podcasts: shorturl.at/bfhHI Anchor: https://anchor.fm/insideexercise Podcast Addict: https://podcastaddict.com/podcast/4025218 Not medical advice
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