Your Brain Might Be Doing This Right Now

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You might think that activities like reading, completing puzzles, or learning a new language might help to keep your brain fit, right? Well, it turns out that your level of overall physical fitness may actually play a larger role in the health of your brain: According to a recent study published in the journal Neurology, our level of fitness in our midlives might determine how much our brains shrink later on in life. You heard me: Your brain might literally be shrinking. But hey, at least the study also identified a way to stop it, right?

The study looked at data from the Framingham Heart Study, which is an ongoing research study started in 1948 that tracks people's lives in order to better understand the risk and causes of heart disease, as well as the functions of other areas of the body like the brain and bones. The researchers looked at 1,100 of the Framingham study participants who had completed both an MRI scan and a treadmill test — which measured how long they could stay on a treadmill before their heart rate reached 85 percent of their maximum — when they were approximately 40 years old. The data from the treadmill test was used to estimate the study participants' VO2 max, which is the maximum amount of oxygen you can use in your body over the course of 60 seconds. (Your maximum heart rate indicates your level of fitness — that is, the lower your resting heart rate, the more physically fit you probably are — while your VO2 max indicates how efficiently your body is able to use oxygen.) Then, the participants were given the scan and test again 20 years later. It's worth noting that none of the participants had heart disease or dementia at the time of their initial exams; the question 20 years later was about whether these things might have changed, and if so, how.

The researchers found that those who had the greatest increase in their heart rates and the lowest VO2 maxes during physical activity when they were 40 years old had the most brain shrinkage over the next 20 years. Essentially, this means that the people who were less physically fit or who could not use oxygen efficiently in their bodies at 40 were the most likely to suffer from the deterioration of brain health 20 years later.

Senior author Dr. Sudha Seshadri, and professor at Boston University School of Medicine, told LiveScience that their conclusion reveals much about how fitness influences our cognitive functioning: "Atrophy correlates with fewer [brain] cells and less rich synaptic connections," she said. Dr. Jennifer Molano, who was not involved in the study, commented to LiveScience that the study's finding correlation, not causation, suggests that further research needs to be done to fully understand this relationship; however, she also noted that the finding "emphasizes the need to encourage exercise in midlife to promote healthy cognitive aging and reduce brain atrophy."

Other research has also found connections between physical fitness and activity levels and cognitive functioning, so this new study appears to support previous results. For example, a 2011 meta-analysis of studies on cognitive decline and physical activity published in the Journal of Internal Medicine found "a significant and consistent protection for all levels of physical activity against the occurrence of cognitive decline." Meanwhile, a 2012 study on ageing found that physical activity could be a potential protection against cognitive decline, while a study published in Alzheimer's & Dementia in 2014 found that engaging in exercise in midlife can help to prevent the development of dementia in old age. Another study published in Neurology in 2014 also found that young people who participate in aerobic exercise have better memory in their middle age.

Thus, it seems that we can see a link emerging between physical activity and cognitive ability as we age, which is definitely a good push to start working out now. The good news is that we still have a lot of time to get in shape before we become old geezers living in retirement, so start pumping the iron now!

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