‘Physical activity boosts mental capacity’

*As high-fat diet shrinks cognitive ability, prompts immune cells to start eating connections between neurons

CAN at least 30 minutes of exercise everyday boost memory, mental capacity and academic performance? Yes and yes again! Testimonies of so many scholars are now being supported by published scientific studies.

Indeed, the list of health benefits that accompany staying physically active is lengthy, but a new study suggests a further advantage; older adults who take more steps – either by walking or jogging – score better on memory tasks than their sedentary peers.

The study shows that simple changes to physical activities – such as walking, taking the stairs or even frolicking on the beach – can result in better memory for older adults.

The study, which is published in the Journal of the International Neuropsychological Society, could have implications for the fight against memory decline brought on by aging and neurodegenerative dementias, such as Alzheimer’s disease.

Meanwhile, scientists say when a high-fat diet causes us to become obese, it also appears to prompt normally bustling immune cells in our brain to become sedentary and start consuming the connections between our neurons.

The good news is going back on a low-fat diet for just two months, at least in mice, reverses this trend of shrinking cognitive ability as weight begins to normalize, said Dr. Alexis M. Stranahan, neuroscientist in the Department of Neuroscience and Regenerative Medicine at the Medical College of Georgia, United States (US).

“Microglia eating synapses is contributing to synapse loss and cognitive impairment in obesity,” Stranahan said. “On the one hand, that is very scary, but it’s also reversible, meaning that if you go back on a low-fat diet that does not even completely wipe out the adiposity, you can completely reverse these cellular processes in the brain and maintain cognition.”

Stranahan is the corresponding author of the study in the journal Brain, Behavior, and Immunity, which provides some of the first evidence of why fat is bad for the brain.

The trouble appears to start with too much fat in the body producing chronic inflammation, which stimulates microglia to have an autoimmune response. Microglia, like macrophages in the body, are known for their ability to ingest trash and infectious agents in the brain, and their highly acidic interior gets rids of it, which helps support the function and health of neurons. But as mice get obese, their microglia seem focused on overeating.

Meanwhile, Dr. Scott Hayes, from Boston University School of Medicine, MA, United States (US) and associate director of the Neuroimaging Research for Veterans Center, who led the memory study and his colleagues note that until now, few studies have objectively examined physical activity in both young and older adults, and investigated whether physical activity is associated with cognition in aging.

To conduct their study, the researchers had 29 young adults between the ages of 18 to 31 and 31 older adults between the ages of 55 to 82 wear an ActiGraph – a small device that records information on how many steps are taken, how vigorous the steps are and how much time is involved.

Rather than using self-reported questionnaires – which previous studies have utilized and can be impacted by memory failures or biases – the current study used this objective measure of physical activity, which the researchers say is a key component.

The participants also underwent neuropsychological testing so the researchers could assess their memory, planning and problem-solving skills. After these tests, the participants took part in a laboratory task that involved learning face-name associations.

Overall, the older adults who took more steps each day performed better on the memory tests than their more sedentary counterparts, the researchers observed.

Furthermore, the link between number of steps taken and memory was strongest with a task that involved matching a person’s face with their name, which is the same type of information that older adults typically have a problem recalling.

The researchers say these types of tasks are likely more difficult for older individuals because they make strong demands on the hippocampus.

Interestingly, the team says that the association between number of steps and memory performance was not observed in young adults.

Meanwhile, according to a 2013 research, intensive exercise improves the academic performance of teenagers.

The study, of about 5,000 children, found links between exercise and exam success in English, maths and science.

It found an increase in performance for every extra 17 minutes boys exercised, and 12 minutes for girls.

The study by the universities of Strathclyde and Dundee found physical activity particularly benefited girls’ performance at science.

The authors said this could be a chance finding or reflect gender differences in the impact of physical activity on the brain.

Children who carried out regular exercise, not only did better academically at 11 but also at 13 and in their exams at 16, the study suggested.

Most of the teenagers’ exercise levels were found to be well below the recommended 60 minutes a day.

The authors speculated what might happen to academic performance if children got the recommended amount.

They claimed that since every 15 minutes of exercise improved performance by an average of about a quarter of a grade, it was possible children who carried out 60 minutes of exercise every day could improve their academic performance by a full grade – for example, from a C to a B, or a B to an A.

However, the authors admitted this was speculation given that very few children did anywhere near this amount of exercise.